Merge with develop branch

CHANGELOG.md

@@ -9,9 +9,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 - Introduced merge detection for receive hooks ([#1278](https://github.com/scm-manager/scm-manager/pull/1278))
 - Anonymous mode for the web ui ([#1284](https://github.com/scm-manager/scm-manager/pull/1284))
+- Check versions of plugin dependencies on plugin installation ([#1283](https://github.com/scm-manager/scm-manager/pull/1283))
 
 ### Fixed
 - Repository names may not end with ".git" ([#1277](https://github.com/scm-manager/scm-manager/pull/1277))
+- Add preselected value to options in dropdown component if missing ([#1287](https://github.com/scm-manager/scm-manager/pull/1287))
 
 ## [2.3.1] - 2020-08-04
 ### Added

pom.xml

@@ -893,7 +893,7 @@
     <servlet.version>3.1.0</servlet.version>
 
     <jaxrs.version>2.1.1</jaxrs.version>
-    <resteasy.version>4.5.5.Final</resteasy.version>
+    <resteasy.version>4.5.6.Final</resteasy.version>
     <jersey-client.version>1.19.4</jersey-client.version>
     <jackson.version>2.11.1</jackson.version>
     <guice.version>4.2.3</guice.version>

scm-core/src/main/java/sonia/scm/plugin/InstalledPluginDescriptor.java

@@ -21,7 +21,7 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  */
-    
+
 package sonia.scm.plugin;
 
 //~--- non-JDK imports --------------------------------------------------------
@@ -37,6 +37,7 @@ import javax.xml.bind.annotation.XmlElement;
 import javax.xml.bind.annotation.XmlElementWrapper;
 import javax.xml.bind.annotation.XmlRootElement;
 import java.util.Set;
+import java.util.stream.Collectors;
 
 //~--- JDK imports ------------------------------------------------------------
 
@@ -67,7 +68,12 @@ public final class InstalledPluginDescriptor extends ScmModule implements Plugin
    * @param condition
    * @param childFirstClassLoader
    * @param dependencies
+   *
+   * @deprecated this constructor uses dependencies with plain strings,
+   *             which is deprecated because the version information is missing.
+   *             This class should not instantiated manually, it is designed to be loaded by jaxb.
    */
+  @Deprecated
   public InstalledPluginDescriptor(int scmVersion, PluginInformation information,
                                    PluginResources resources, PluginCondition condition,
                                    boolean childFirstClassLoader, Set<String> dependencies, Set<String> optionalDependencies)
@@ -77,8 +83,17 @@ public final class InstalledPluginDescriptor extends ScmModule implements Plugin
     this.resources = resources;
     this.condition = condition;
     this.childFirstClassLoader = childFirstClassLoader;
-    this.dependencies = dependencies;
+    this.dependencies = mapToNameAndVersionSet(dependencies);
-    this.optionalDependencies = optionalDependencies;
+    this.optionalDependencies = mapToNameAndVersionSet(optionalDependencies);
+  }
+
+  private static Set<NameAndVersion> mapToNameAndVersionSet(Set<String> dependencies) {
+    if (dependencies == null){
+      return ImmutableSet.of();
+    }
+    return dependencies.stream()
+      .map(d -> new NameAndVersion(d, null))
+      .collect(Collectors.toSet());
   }
 
   //~--- methods --------------------------------------------------------------
@@ -173,13 +188,19 @@ public final class InstalledPluginDescriptor extends ScmModule implements Plugin
    * @since 2.0.0
    */
   @Override
-  public Set<String> getDependencies()
+  public Set<String> getDependencies() {
-  {
+    return mapToStringSet(getDependenciesWithVersion());
-    if (dependencies == null)
+  }
-    {
+
+  /**
+   * Returns name and versions of the plugins which are this plugin depends on.
+   * @return dependencies with their versions
+   * @since 2.4.0
+   */
+  public Set<NameAndVersion> getDependenciesWithVersion() {
+    if (dependencies == null) {
       dependencies = ImmutableSet.of();
     }
-
     return dependencies;
   }
 
@@ -193,11 +214,18 @@ public final class InstalledPluginDescriptor extends ScmModule implements Plugin
    */
   @Override
   public Set<String> getOptionalDependencies() {
-    if (optionalDependencies == null)
+    return mapToStringSet(getOptionalDependenciesWithVersion());
-    {
+  }
+
+  /**
+   * Returns name and versions of the plugins which are this plugin optional depends on.
+   * @return optional dependencies with their versions
+   * @since 2.4.0
+   */
+  public Set<NameAndVersion> getOptionalDependenciesWithVersion() {
+    if (optionalDependencies == null) {
       optionalDependencies = ImmutableSet.of();
     }
-
     return optionalDependencies;
   }
 
@@ -205,6 +233,12 @@ public final class InstalledPluginDescriptor extends ScmModule implements Plugin
     return ImmutableSet.copyOf(Iterables.concat(getDependencies(), getOptionalDependencies()));
   }
 
+  private Set<String> mapToStringSet(Set<NameAndVersion> dependencies) {
+    return dependencies.stream()
+      .map(NameAndVersion::getName)
+      .collect(Collectors.toSet());
+  }
+
   /**
    * Method description
    *
@@ -263,12 +297,12 @@ public final class InstalledPluginDescriptor extends ScmModule implements Plugin
   /** Field description */
   @XmlElement(name = "dependency")
   @XmlElementWrapper(name = "dependencies")
-  private Set<String> dependencies;
+  private Set<NameAndVersion> dependencies;
 
   /** Field description */
   @XmlElement(name = "dependency")
   @XmlElementWrapper(name = "optional-dependencies")
-  private Set<String> optionalDependencies;
+  private Set<NameAndVersion> optionalDependencies;
 
   /** Field description */
   @XmlElement(name = "information")

scm-core/src/main/java/sonia/scm/plugin/NameAndVersion.java

@@ -0,0 +1,104 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020-present Cloudogu GmbH and Contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package sonia.scm.plugin;
+
+import com.google.common.base.Strings;
+import lombok.EqualsAndHashCode;
+import lombok.Getter;
+import sonia.scm.version.Version;
+
+import javax.xml.bind.annotation.XmlAccessType;
+import javax.xml.bind.annotation.XmlAccessorType;
+import javax.xml.bind.annotation.XmlAttribute;
+import javax.xml.bind.annotation.XmlValue;
+import javax.xml.bind.annotation.adapters.XmlAdapter;
+import javax.xml.bind.annotation.adapters.XmlJavaTypeAdapter;
+import java.util.Optional;
+
+/**
+ * @since 2.4.0
+ */
+@Getter
+@EqualsAndHashCode
+@XmlAccessorType(XmlAccessType.FIELD)
+public class NameAndVersion {
+
+  @XmlValue
+  private String name;
+
+  @XmlAttribute(name = "version")
+  @XmlJavaTypeAdapter(VersionXmlAdapter.class)
+  private Version version;
+
+  NameAndVersion() {
+    // required for jaxb
+  }
+
+  public NameAndVersion(String name) {
+    this(name, null);
+  }
+
+  public NameAndVersion(String name, String version) {
+    this.name = name;
+    if (!Strings.isNullOrEmpty(version)) {
+      this.version = Version.parse(version);
+    }
+  }
+
+  public Optional<Version> getVersion() {
+    return Optional.ofNullable(version);
+  }
+
+  public Version mustGetVersion() {
+    if (version == null) {
+      throw new IllegalStateException("version is not set");
+    }
+    return version;
+  }
+
+  @Override
+  public String toString() {
+    return name + (version != null ? ":" + version.getParsedVersion() : "");
+  }
+
+  static class VersionXmlAdapter extends XmlAdapter<String, Version> {
+
+    @Override
+    public Version unmarshal(String v) {
+      if (Strings.isNullOrEmpty(v)) {
+        return null;
+      }
+      return Version.parse(v);
+    }
+
+    @Override
+    public String marshal(Version v) {
+      if (v != null) {
+        return v.getUnparsedVersion();
+      }
+      return null;
+    }
+  }
+}

scm-core/src/main/java/sonia/scm/util/ValidationUtil.java

@@ -47,7 +47,7 @@ public final class ValidationUtil
   public static final String REGEX_NAME =
     "^[A-Za-z0-9\\.\\-_][A-Za-z0-9\\.\\-_@]*$";
 
-  public static final String REGEX_REPOSITORYNAME = "(?!^\\.\\.$)(?!^\\.$)(?!.*[\\\\\\[\\]])^[A-Za-z0-9\\.][A-Za-z0-9\\.\\-_]*$";
+  public static final String REGEX_REPOSITORYNAME = "(?!^\\.\\.$)(?!^\\.$)(?!.*[\\\\\\[\\]])(?!.*[.]git$)^[A-Za-z0-9\\.][A-Za-z0-9\\.\\-_]*$";
 
   /** Field description */
   private static final Pattern PATTERN_REPOSITORYNAME = Pattern.compile(REGEX_REPOSITORYNAME);

scm-core/src/main/java/sonia/scm/version/Version.java

@@ -21,7 +21,7 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  */
-    
+
 package sonia.scm.version;
 
 //~--- non-JDK imports --------------------------------------------------------
@@ -268,11 +268,28 @@ public final class Version implements Comparable<Version>
    *
    * @return true if newer
    */
-  public boolean isNewer(String versionString)
+  public boolean isNewer(String versionString) {
-  {
+    return isNewer(Version.parse(versionString));
-    Version o = Version.parse(versionString);
+  }
 
-    return (o != null) && isNewer(o);
+  /**
+   * Returns true if the given version is newer or equal.
+   * @param versionString other version
+   * @return true if newer
+   * @since 2.4.0
+   */
+  public boolean isNewerOrEqual(String versionString) {
+    return isNewerOrEqual(Version.parse(versionString));
+  }
+
+  /**
+   * Returns true if the given version is newer or equal.
+   * @param o other version
+   * @return {@code true} if newer or equal
+   * @since 2.4.0
+   */
+  public boolean isNewerOrEqual(Version o) {
+    return compareTo(o) <= 0;
   }
 
   /**
@@ -296,13 +313,31 @@ public final class Version implements Comparable<Version>
    *
    * @return true if older
    */
-  public boolean isOlder(String versionString)
+  public boolean isOlder(String versionString) {
-  {
+    return isOlder(Version.parse(versionString));
-    Version o = Version.parse(versionString);
-
-    return (o != null) && isOlder(o);
   }
 
+  /**
+   * Returns true if the given version is older or equal.
+   * @param versionString other version
+   * @return {@code true} if older or equal
+   * @since 2.4.0
+   */
+  public boolean isOlderOrEqual(String versionString) {
+    return isOlderOrEqual(Version.parse(versionString));
+  }
+
+  /**
+   * Returns true if the given version is older or equal.
+   * @param o other version
+   * @return {@code true} if older or equal
+   * @since 2.4.0
+   */
+  public boolean isOlderOrEqual(Version o) {
+    return compareTo(o) >= 0;
+  }
+
+
   /**
    * Returns true if the version is a snapshot.
    *

scm-core/src/test/java/sonia/scm/plugin/InstalledPluginDescriptorTest.java

@@ -0,0 +1,63 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020-present Cloudogu GmbH and Contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package sonia.scm.plugin;
+
+import com.google.common.io.Resources;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+
+import javax.xml.bind.JAXB;
+import java.net.URL;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class InstalledPluginDescriptorTest {
+
+  private static InstalledPluginDescriptor descriptor;
+
+  @BeforeAll
+  @SuppressWarnings("UnstableApiUsage")
+  static void unmarshal() {
+    URL resource = Resources.getResource("sonia/scm/plugin/review-plugin.xml");
+    descriptor = JAXB.unmarshal(resource, InstalledPluginDescriptor.class);
+  }
+
+  @Test
+  void shouldUnmarshallDependencies() {
+    assertThat(descriptor.getDependencies()).containsOnly("scm-mail-plugin");
+    assertThat(descriptor.getOptionalDependencies()).containsOnly("scm-editor-plugin", "scm-landingpage-plugin");
+    assertThat(descriptor.getDependenciesInclusiveOptionals()).containsOnly("scm-mail-plugin", "scm-editor-plugin", "scm-landingpage-plugin");
+  }
+
+  @Test
+  void shouldUnmarshallDependenciesWithVersion() {
+    assertThat(descriptor.getDependenciesWithVersion()).containsOnly(new NameAndVersion("scm-mail-plugin", "2.1.0"));
+    assertThat(descriptor.getOptionalDependenciesWithVersion()).containsOnly(
+      new NameAndVersion("scm-landingpage-plugin", "1.0.0"),
+      new NameAndVersion("scm-editor-plugin")
+    );
+  }
+
+}

scm-core/src/test/java/sonia/scm/util/ValidationUtilTest.java

@@ -202,7 +202,9 @@ public class ValidationUtilTest
       "scm/main",
       "scm/plugins/git-plugin",
       "_scm",
-      "-scm"
+      "-scm",
+      "scm.git",
+      "scm.git.git"
     };
 
     for (String path : validPaths) {

scm-core/src/test/java/sonia/scm/version/VersionTest.java

@@ -21,96 +21,77 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  */
-    
+
 package sonia.scm.version;
 
-//~--- non-JDK imports --------------------------------------------------------
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
-
-import static org.junit.Assert.*;
-
-//~--- JDK imports ------------------------------------------------------------
 
 import java.util.Arrays;
 
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
 /**
- *
  * @author Sebastian Sdorra
  */
-public class VersionTest
+class VersionTest {
-{
 
-  /**
-   * Method description
-   *
-   */
   @Test
-  public void parseSimpleVersion()
+  void parseSimpleVersion() {
-  {
     Version v = Version.parse("1.0");
 
-    assertTrue(v.getMajor() == 1);
+    assertThat(v.getMajor()).isOne();
-    assertTrue(v.getMinor() == 0);
+    assertThat(v.getMinor()).isZero();
-    assertTrue(v.getPatch() == 0);
+    assertThat(v.getPatch()).isZero();
-    assertFalse(v.isSnapshot());
+    assertThat(v.isSnapshot()).isFalse();
-    assertTrue(v.getType() == VersionType.RELEASE);
+    assertThat(v.getType()).isSameAs(VersionType.RELEASE);
-    assertEquals(v.getParsedVersion(), "1.0.0");
+    assertThat(v.getParsedVersion()).isEqualTo("1.0.0");
 
     // test with snapshot
     v = Version.parse("1.1-SNAPSHOT");
-    assertTrue(v.getMajor() == 1);
+    assertThat(v.getMajor()).isOne();
-    assertTrue(v.getMinor() == 1);
+    assertThat(v.getMinor()).isOne();
-    assertTrue(v.getPatch() == 0);
+    assertThat(v.getPatch()).isZero();
-    assertTrue(v.isSnapshot());
+    assertThat(v.isSnapshot()).isTrue();
-    assertTrue(v.getType() == VersionType.RELEASE);
+    assertThat(v.getType()).isSameAs(VersionType.RELEASE);
-    assertEquals(v.getParsedVersion(), "1.1.0-SNAPSHOT");
+    assertThat(v.getParsedVersion()).isEqualTo("1.1.0-SNAPSHOT");
 
     // test with maintenance
     v = Version.parse("2.3.14");
-    assertTrue(v.getMajor() == 2);
+    assertThat(v.getMajor()).isEqualTo(2);
-    assertTrue(v.getMinor() == 3);
+    assertThat(v.getMinor()).isEqualTo(3);
-    assertTrue(v.getPatch() == 14);
+    assertThat(v.getPatch()).isEqualTo(14);
-    assertFalse(v.isSnapshot());
+    assertThat(v.isSnapshot()).isFalse();
-    assertTrue(v.getType() == VersionType.RELEASE);
+    assertThat(v.getType()).isSameAs(VersionType.RELEASE);
-    assertEquals(v.getParsedVersion(), "2.3.14");
+    assertThat(v.getParsedVersion()).isEqualTo("2.3.14");
   }
 
-  /**
-   * Method description
-   *
-   */
   @Test
-  public void parseTypeVersions()
+  void parseTypeVersions() {
-  {
     Version v = Version.parse("1.0-alpha");
 
-    assertTrue(v.getMajor() == 1);
+    assertThat(v.getMajor()).isOne();
-    assertTrue(v.getMinor() == 0);
+    assertThat(v.getMinor()).isZero();
-    assertTrue(v.getPatch() == 0);
+    assertThat(v.getPatch()).isZero();
-    assertFalse(v.isSnapshot());
+    assertThat(v.isSnapshot()).isFalse();
-    assertTrue(v.getType() == VersionType.ALPHA);
+    assertThat(v.getType()).isSameAs(VersionType.ALPHA);
-    assertTrue(v.getTypeVersion() == 1);
+    assertThat(v.getTypeVersion()).isOne();
-    assertEquals(v.getParsedVersion(), "1.0.0-alpha1");
+    assertThat(v.getParsedVersion()).isEqualTo("1.0.0-alpha1");
 
     // Test release candidate
     v = Version.parse("2.1.2-RC3");
-    assertTrue(v.getMajor() == 2);
+    assertThat(v.getMajor()).isEqualTo(2);
-    assertTrue(v.getMinor() == 1);
+    assertThat(v.getMinor()).isEqualTo(1);
-    assertTrue(v.getPatch() == 2);
+    assertThat(v.getPatch()).isEqualTo(2);
-    assertFalse(v.isSnapshot());
+    assertThat(v.isSnapshot()).isFalse();
-    assertTrue(v.getType() == VersionType.RELEASE_CANDIDAT);
+    assertThat(v.getType()).isSameAs(VersionType.RELEASE_CANDIDAT);
-    assertTrue(v.getTypeVersion() == 3);
+    assertThat(v.getTypeVersion()).isEqualTo(3);
-    assertEquals(v.getParsedVersion(), "2.1.2-RC3");
+    assertThat(v.getParsedVersion()).isEqualTo("2.1.2-RC3");
   }
 
-  /**
-   * Method description
-   *
-   */
   @Test
-  public void testCompareTo()
+  void testCompareTo() {
-  {
     Version[] versions = new Version[9];
 
     versions[0] = Version.parse("2.3.1-SNAPSHOT");
@@ -123,48 +104,45 @@ public class VersionTest
     versions[7] = Version.parse("2.3");
     versions[8] = Version.parse("2.4.6");
     Arrays.sort(versions);
-    assertEquals(versions[0].getParsedVersion(), "2.4.6");
+    assertThat(versions[0].getParsedVersion()).isEqualTo("2.4.6");
-    assertEquals(versions[1].getParsedVersion(), "2.3.1");
+    assertThat(versions[1].getParsedVersion()).isEqualTo("2.3.1");
-    assertEquals(versions[2].getParsedVersion(), "2.3.1-SNAPSHOT");
+    assertThat(versions[2].getParsedVersion()).isEqualTo("2.3.1-SNAPSHOT");
-    assertEquals(versions[3].getParsedVersion(), "2.3.1-RC1");
+    assertThat(versions[3].getParsedVersion()).isEqualTo("2.3.1-RC1");
-    assertEquals(versions[4].getParsedVersion(), "2.3.1-beta2");
+    assertThat(versions[4].getParsedVersion()).isEqualTo("2.3.1-beta2");
-    assertEquals(versions[5].getParsedVersion(), "2.3.1-beta1");
+    assertThat(versions[5].getParsedVersion()).isEqualTo("2.3.1-beta1");
-    assertEquals(versions[6].getParsedVersion(), "2.3.1-alpha2");
+    assertThat(versions[6].getParsedVersion()).isEqualTo("2.3.1-alpha2");
-    assertEquals(versions[7].getParsedVersion(), "2.3.1-M1");
+    assertThat(versions[7].getParsedVersion()).isEqualTo("2.3.1-M1");
-    assertEquals(versions[8].getParsedVersion(), "2.3.0");
+    assertThat(versions[8].getParsedVersion()).isEqualTo("2.3.0");
   }
 
-  /**
-   * Method description
-   *
-   */
   @Test
-  public void testIsNewer()
+  void testIsNewer() {
-  {
+    assertThat(Version.parse("1.0").isNewer("1.0.1")).isFalse();
-    assertFalse(Version.parse("1.0").isNewer("1.0.1"));
+    assertThat(Version.parse("1.1").isNewer("1.1-alpha1")).isTrue();
-    assertTrue(Version.parse("1.1").isNewer("1.1-alpha1"));
+    assertThat(Version.parse("1.1").isNewer("1.1-RC5")).isTrue();
-    assertTrue(Version.parse("1.1").isNewer("1.1-RC5"));
   }
 
-  /**
-   * Method description
-   *
-   */
   @Test
-  public void testIsOlder()
+  void testIsOlder() {
-  {
+    assertThat(Version.parse("1.0.1").isOlder("1.0")).isFalse();
-    assertFalse(Version.parse("1.0.1").isOlder("1.0"));
+    assertThat(Version.parse("1.1-alpha1").isOlder("1.1")).isTrue();
-    assertTrue(Version.parse("1.1-alpha1").isOlder("1.1"));
+    assertThat(Version.parse("1.1-RC5").isOlder("1.1")).isTrue();
-    assertTrue(Version.parse("1.1-RC5").isOlder("1.1"));
   }
 
-  /**
+  @Test
-   * Method description
+  void testIsOlderOrEqual() {
-   *
+    assertThat(Version.parse("1.0.0").isOlderOrEqual("1.0.1")).isTrue();
-   */
+    assertThat(Version.parse("1.0.1").isOlderOrEqual("1.0.1")).isTrue();
-  @Test(expected = VersionParseException.class)
+  }
-  public void testUnparseable()
+
-  {
+  @Test
-    Version.parse("aaaa");
+  void testINewerOrEqual() {
+    assertThat(Version.parse("1.0.1").isNewerOrEqual("1.0.0")).isTrue();
+    assertThat(Version.parse("1.0.1").isOlderOrEqual("1.0.1")).isTrue();
+  }
+
+  @Test
+  void testUnparseable() {
+    assertThrows(VersionParseException.class, () -> Version.parse("aaaa"));
   }
 }

scm-core/src/test/resources/sonia/scm/plugin/review-plugin.xml

@@ -0,0 +1,74 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!--
+
+    MIT License
+
+    Copyright (c) 2020-present Cloudogu GmbH and Contributors
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in all
+    copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+    SOFTWARE.
+
+-->
+<plugin>
+  <scm-version>2</scm-version>
+  <information>
+    <displayName>Review</displayName>
+    <author>Cloudogu GmbH</author>
+    <category>Workflow</category>
+    <name>scm-review-plugin</name>
+    <version>2.3.0-SNAPSHOT</version>
+    <description>Depict a review process with pull requests</description>
+  </information>
+  <conditions>
+    <min-version>2.4.0-SNAPSHOT</min-version>
+  </conditions>
+  <resources>
+    <script>assets/scm-review-plugin.bundle.js</script>
+  </resources>
+  <subscriber>
+    <class>com.cloudogu.scm.review.emailnotification.EmailNotificationHook</class>
+    <event>com.cloudogu.scm.review.pullrequest.service.PullRequestRejectedEvent</event>
+  </subscriber>
+  <extension-point>
+    <description>Each {@link Rule} class implementation defines a type of workflow rule.&lt;br&gt;
+      &lt;br&gt;
+      Rules applied to your repositories are represented by {@link AppliedRule}s&lt;br&gt;
+      to support multiple {@link Rule}s of the same type with distinct configuration.
+    </description>
+    <autoBind>true</autoBind>
+    <multi>true</multi>
+    <class>com.cloudogu.scm.review.workflow.Rule</class>
+  </extension-point>
+  <rest-resource>
+    <value>v2/pull-requests</value>
+    <class>com.cloudogu.scm.review.config.api.RepositoryConfigResource</class>
+  </rest-resource>
+  <event>
+    <class>com.cloudogu.scm.review.pullrequest.service.PullRequestEvent</class>
+  </event>
+  <extension>
+    <class>com.cloudogu.scm.review.ProcessChangedFilesHook</class>
+  </extension>
+  <dependencies>
+    <dependency version="2.1.0">scm-mail-plugin</dependency>
+  </dependencies>
+  <optional-dependencies>
+    <dependency>scm-editor-plugin</dependency>
+    <dependency version="1.0.0">scm-landingpage-plugin</dependency>
+  </optional-dependencies>
+</plugin>

scm-ui/ui-components/src/__snapshots__/storyshots.test.ts.snap

@@ -38608,6 +38608,42 @@ exports[`Storyshots Forms|Checkbox With HelpText 1`] = `
 </div>
 `;
 
+exports[`Storyshots Forms|DropDown Add preselect if missing in options 1`] = `
+<div
+  className="select"
+>
+  <select
+    onChange={[Function]}
+    value="D"
+  >
+    <option
+      selected={false}
+      value="alpha"
+    >
+      A
+    </option>
+    <option
+      selected={false}
+      value="beta"
+    >
+      B
+    </option>
+    <option
+      selected={false}
+      value="gamma"
+    >
+      C
+    </option>
+    <option
+      selected={true}
+      value="D"
+    >
+      D
+    </option>
+  </select>
+</div>
+`;
+
 exports[`Storyshots Forms|DropDown Default 1`] = `
 <div
   className="select"
@@ -38664,6 +38700,12 @@ exports[`Storyshots Forms|DropDown With Translation 1`] = `
     >
       The Meaning Of Liff
     </option>
+    <option
+      selected={true}
+      value="dirk"
+    >
+      dirk
+    </option>
   </select>
 </div>
 `;

scm-ui/ui-components/src/forms/DropDown.stories.tsx

@@ -48,4 +48,14 @@ storiesOf("Forms|DropDown", module)
         // nothing to do
       }}
     />
+  ))
+  .add("Add preselect if missing in options", () => (
+    <DropDown
+      optionValues={["alpha", "beta", "gamma"]}
+      options={["A", "B", "C"]}
+      preselectedOption={"D"}
+      optionSelected={selection => {
+        // nothing to do
+      }}
+    />
   ));

scm-ui/ui-components/src/forms/DropDown.tsx

@@ -36,6 +36,11 @@ type Props = {
 class DropDown extends React.Component<Props> {
   render() {
     const { options, optionValues, preselectedOption, className, disabled } = this.props;
+
+    if (preselectedOption && options.filter(o => o === preselectedOption).length === 0) {
+      options.push(preselectedOption);
+    }
+
     return (
       <div className={classNames(className, "select", disabled ? "disabled" : "")}>
         <select value={preselectedOption ? preselectedOption : ""} onChange={this.change} disabled={disabled}>

scm-webapp/src/main/java/sonia/scm/plugin/DefaultPluginManager.java

@@ -42,6 +42,7 @@ import java.util.Collection;
 import java.util.List;
 import java.util.Optional;
 import java.util.Set;
+import java.util.function.Function;
 import java.util.function.Predicate;
 import java.util.stream.Collectors;
 
@@ -68,17 +69,30 @@ public class DefaultPluginManager implements PluginManager {
   private final Collection<PendingPluginUninstallation> pendingUninstallQueue = new ArrayList<>();
   private final PluginDependencyTracker dependencyTracker = new PluginDependencyTracker();
 
+  private final Function<List<AvailablePlugin>, PluginInstallationContext> contextFactory;
+
   @Inject
   public DefaultPluginManager(PluginLoader loader, PluginCenter center, PluginInstaller installer, Restarter restarter, ScmEventBus eventBus) {
+    this(loader, center, installer, restarter, eventBus, null);
+  }
+
+  DefaultPluginManager(PluginLoader loader, PluginCenter center, PluginInstaller installer, Restarter restarter, ScmEventBus eventBus, Function<List<AvailablePlugin>, PluginInstallationContext> contextFactory) {
     this.loader = loader;
     this.center = center;
     this.installer = installer;
     this.restarter = restarter;
     this.eventBus = eventBus;
 
+    if (contextFactory != null) {
+      this.contextFactory = contextFactory;
+    } else {
+      this.contextFactory = (availablePlugins -> PluginInstallationContext.from(getInstalled(), availablePlugins));
+    }
+
     this.computeInstallationDependencies();
   }
 
+
   @VisibleForTesting
   synchronized void computeInstallationDependencies() {
     loader.getInstalledPlugins()
@@ -167,9 +181,10 @@ public class DefaultPluginManager implements PluginManager {
 
     List<AvailablePlugin> plugins = collectPluginsToInstall(name);
     List<PendingPluginInstallation> pendingInstallations = new ArrayList<>();
+
     for (AvailablePlugin plugin : plugins) {
       try {
-        PendingPluginInstallation pending = installer.install(plugin);
+        PendingPluginInstallation pending = installer.install(contextFactory.apply(plugins), plugin);
         dependencyTracker.addInstalled(plugin.getDescriptor());
         pendingInstallations.add(pending);
         eventBus.post(new PluginEvent(PluginEvent.PluginEventType.INSTALLED, plugin));

scm-webapp/src/main/java/sonia/scm/plugin/DependencyNotFoundException.java

@@ -0,0 +1,62 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020-present Cloudogu GmbH and Contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package sonia.scm.plugin;
+
+import static sonia.scm.ContextEntry.ContextBuilder.entity;
+
+@SuppressWarnings("squid:MaximumInheritanceDepth") // exceptions have a deep inheritance depth themselves; therefore we accept this here
+public class DependencyNotFoundException extends PluginInstallException {
+
+  private final String plugin;
+  private final String missingDependency;
+
+  public DependencyNotFoundException(String plugin, String missingDependency) {
+    super(
+      entity("Dependency", missingDependency)
+        .in("Plugin", plugin)
+        .build(),
+      String.format(
+        "missing dependency %s of plugin %s",
+        missingDependency,
+        plugin
+      )
+    );
+    this.plugin = plugin;
+    this.missingDependency = missingDependency;
+  }
+
+  public String getPlugin() {
+    return plugin;
+  }
+
+  public String getMissingDependency() {
+    return missingDependency;
+  }
+
+  @Override
+  public String getCode() {
+    return "5GS6lwvWF1";
+  }
+}

scm-webapp/src/main/java/sonia/scm/plugin/DependencyVersionMismatchException.java

@@ -0,0 +1,60 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020-present Cloudogu GmbH and Contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package sonia.scm.plugin;
+
+import lombok.Getter;
+
+import static sonia.scm.ContextEntry.ContextBuilder.entity;
+
+@Getter
+@SuppressWarnings("squid:MaximumInheritanceDepth") // exceptions have a deep inheritance depth themselves; therefore we accept this here
+public class DependencyVersionMismatchException extends PluginInstallException {
+
+  private final String plugin;
+  private final String dependency;
+  private final String minVersion;
+  private final String currentVersion;
+
+  public DependencyVersionMismatchException(String plugin, String dependency, String minVersion, String currentVersion) {
+    super(
+      entity("Dependency", dependency)
+        .in("Plugin", plugin)
+        .build(),
+      String.format(
+        "%s requires dependency %s at least in version %s, but it is installed in version %s",
+        plugin, dependency, minVersion, currentVersion
+      )
+    );
+    this.plugin = plugin;
+    this.dependency = dependency;
+    this.minVersion = minVersion;
+    this.currentVersion = currentVersion;
+  }
+
+  @Override
+  public String getCode() {
+    return "E5S6niWwi1";
+  }
+}

scm-webapp/src/main/java/sonia/scm/plugin/ExplodedSmp.java

@@ -21,7 +21,7 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  */
-    
+
 package sonia.scm.plugin;
 
 //~--- non-JDK imports --------------------------------------------------------
@@ -30,11 +30,10 @@ import com.google.common.base.Function;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-//~--- JDK imports ------------------------------------------------------------
-
 import java.nio.file.Path;
+import java.util.Objects;
 
-import java.util.Set;
+//~--- JDK imports ------------------------------------------------------------
 
 /**
  * The ExplodedSmp object represents an extracted SCM-Manager plugin. The object
@@ -107,6 +106,25 @@ public final class ExplodedSmp
     return plugin;
   }
 
+  @Override
+  public boolean equals(Object o) {
+    if (this == o) return true;
+    if (o == null || getClass() != o.getClass()) return false;
+    ExplodedSmp that = (ExplodedSmp) o;
+    return path.equals(that.path);
+  }
+
+  @Override
+  public int hashCode() {
+    return Objects.hash(path);
+  }
+
+  @Override
+  public String toString() {
+    PluginInformation information = plugin.getInformation();
+    return information.getName() + "@" + information.getVersion() + " (" + path + ")";
+  }
+
   //~--- inner classes --------------------------------------------------------
 
   /**

scm-webapp/src/main/java/sonia/scm/plugin/PluginChecksumMismatchException.java

@@ -26,6 +26,7 @@ package sonia.scm.plugin;
 
 import static sonia.scm.ContextEntry.ContextBuilder.entity;
 
+@SuppressWarnings("squid:MaximumInheritanceDepth") // exceptions have a deep inheritance depth themselves; therefore we accept this here
 public class PluginChecksumMismatchException extends PluginInstallException {
   public PluginChecksumMismatchException(AvailablePlugin plugin, String calculatedChecksum, String expectedChecksum) {
     super(

scm-webapp/src/main/java/sonia/scm/plugin/PluginInformationMismatchException.java

@@ -0,0 +1,51 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020-present Cloudogu GmbH and Contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package sonia.scm.plugin;
+
+import lombok.Getter;
+
+import static sonia.scm.ContextEntry.ContextBuilder.entity;
+
+@Getter
+@SuppressWarnings("squid:MaximumInheritanceDepth") // exceptions have a deep inheritance depth themselves; therefore we accept this here
+public class PluginInformationMismatchException extends PluginInstallException {
+
+  private final PluginInformation api;
+  private final PluginInformation downloaded;
+
+  public PluginInformationMismatchException(PluginInformation api, PluginInformation downloaded, String message) {
+    super(
+      entity("Plugin", api.getName()).build(),
+      message
+    );
+    this.api = api;
+    this.downloaded = downloaded;
+  }
+
+  @Override
+  public String getCode() {
+    return "4RS6niPRX1";
+  }
+}

scm-webapp/src/main/java/sonia/scm/plugin/PluginInstallationContext.java

@@ -0,0 +1,73 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020-present Cloudogu GmbH and Contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package sonia.scm.plugin;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Optional;
+
+public final class PluginInstallationContext {
+
+  private final Map<String, NameAndVersion> dependencies;
+
+  private PluginInstallationContext(Map<String, NameAndVersion> dependencies) {
+    this.dependencies = dependencies;
+  }
+
+  public static PluginInstallationContext empty() {
+    return new PluginInstallationContext(Collections.emptyMap());
+  }
+
+  public static PluginInstallationContext fromDescriptors(Iterable<? extends PluginDescriptor> installed, Iterable<? extends PluginDescriptor> pending) {
+    Map<String, NameAndVersion> dependencies = new HashMap<>();
+    appendDescriptors(dependencies, installed);
+    appendDescriptors(dependencies, pending);
+    return new PluginInstallationContext(dependencies);
+  }
+
+  public static PluginInstallationContext from(Iterable<? extends Plugin> installed, Iterable<? extends Plugin> pending) {
+    Map<String, NameAndVersion> dependencies = new HashMap<>();
+    appendPlugins(dependencies, installed);
+    appendPlugins(dependencies, pending);
+    return new PluginInstallationContext(dependencies);
+  }
+
+  private static <P extends PluginDescriptor> void appendDescriptors(Map<String, NameAndVersion> dependencies, Iterable<P> descriptors) {
+    descriptors.forEach(desc -> appendPlugins(dependencies, desc.getInformation()));
+  }
+
+  private static <P extends Plugin> void appendPlugins(Map<String, NameAndVersion> dependencies, Iterable<P> plugins) {
+    plugins.forEach(plugin -> appendPlugins(dependencies, plugin.getDescriptor().getInformation()));
+  }
+
+  private static void appendPlugins(Map<String, NameAndVersion> dependencies, PluginInformation information) {
+    dependencies.put(information.getName(), new NameAndVersion(information.getName(), information.getVersion()));
+  }
+
+  public Optional<NameAndVersion> find(String name) {
+    return Optional.ofNullable(dependencies.get(name));
+  }
+}

scm-webapp/src/main/java/sonia/scm/plugin/PluginInstallationVerifier.java

@@ -0,0 +1,104 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020-present Cloudogu GmbH and Contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package sonia.scm.plugin;
+
+import sonia.scm.version.Version;
+
+import java.util.Optional;
+import java.util.Set;
+
+public final class PluginInstallationVerifier {
+
+  private final PluginInstallationContext context;
+  private final InstalledPluginDescriptor descriptor;
+
+  private PluginInstallationVerifier(PluginInstallationContext context, InstalledPluginDescriptor descriptor) {
+    this.context = context;
+    this.descriptor = descriptor;
+  }
+
+  public static void verify(PluginInstallationContext context, InstalledPlugin plugin) {
+    verify(context, plugin.getDescriptor());
+  }
+
+  public static void verify(PluginInstallationContext context, InstalledPluginDescriptor descriptor) {
+    new PluginInstallationVerifier(context, descriptor).doVerification();
+  }
+
+  private void doVerification() {
+    verifyConditions();
+    verifyDependencies();
+    verifyOptionalDependencies();
+  }
+
+  private void verifyConditions() {
+    // TODO we should provide more details here, which condition has failed
+    if (!descriptor.getCondition().isSupported()) {
+      throw new PluginConditionFailedException(
+        descriptor.getCondition(),
+        String.format(
+          "could not load plugin %s, the plugin condition does not match",
+          descriptor.getInformation().getName()
+        )
+      );
+    }
+  }
+
+  private void verifyDependencies() {
+    Set<NameAndVersion> dependencies = descriptor.getDependenciesWithVersion();
+    for (NameAndVersion dependency : dependencies) {
+      NameAndVersion installed = context.find(dependency.getName())
+        .orElseThrow(
+          () -> new DependencyNotFoundException(descriptor.getInformation().getName(), dependency.getName())
+        );
+
+      dependency.getVersion().ifPresent(requiredVersion -> verifyDependencyVersion(dependency, installed));
+    }
+  }
+
+  private void verifyOptionalDependencies() {
+    Set<NameAndVersion> dependencies = descriptor.getOptionalDependenciesWithVersion();
+    for (NameAndVersion dependency : dependencies) {
+      Optional<Version> version = dependency.getVersion();
+      if (version.isPresent()) {
+        Optional<NameAndVersion> installed = context.find(dependency.getName());
+        installed.ifPresent(nameAndVersion -> verifyDependencyVersion(dependency, nameAndVersion));
+      }
+    }
+  }
+
+  private void verifyDependencyVersion(NameAndVersion required, NameAndVersion installed) {
+    Version requiredVersion = required.mustGetVersion();
+    Version installedVersion = installed.mustGetVersion();
+    if (installedVersion.isOlder(requiredVersion)) {
+      throw new DependencyVersionMismatchException(
+        descriptor.getInformation().getName(),
+        required.getName(),
+        requiredVersion.getUnparsedVersion(),
+        installedVersion.getUnparsedVersion()
+      );
+    }
+  }
+}

scm-webapp/src/main/java/sonia/scm/plugin/PluginInstaller.java

@@ -38,36 +38,72 @@ import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.Optional;
 
-@SuppressWarnings("UnstableApiUsage") // guava hash is marked as unstable
+@SuppressWarnings("UnstableApiUsage")
+  // guava hash is marked as unstable
 class PluginInstaller {
 
-  private final SCMContextProvider context;
+  private final SCMContextProvider scmContext;
   private final AdvancedHttpClient client;
   private final SmpDescriptorExtractor smpDescriptorExtractor;
 
   @Inject
-  public PluginInstaller(SCMContextProvider context, AdvancedHttpClient client, SmpDescriptorExtractor smpDescriptorExtractor) {
+  public PluginInstaller(SCMContextProvider scmContext, AdvancedHttpClient client, SmpDescriptorExtractor smpDescriptorExtractor) {
-    this.context = context;
+    this.scmContext = scmContext;
     this.client = client;
     this.smpDescriptorExtractor = smpDescriptorExtractor;
   }
 
   @SuppressWarnings("squid:S4790") // hashing should be safe
-  public PendingPluginInstallation install(AvailablePlugin plugin) {
+  public PendingPluginInstallation install(PluginInstallationContext context, AvailablePlugin plugin) {
     Path file = null;
     try (HashingInputStream input = new HashingInputStream(Hashing.sha256(), download(plugin))) {
       file = createFile(plugin);
       Files.copy(input, file);
 
       verifyChecksum(plugin, input.hash(), file);
-      verifyConditions(plugin, file);
+
+      InstalledPluginDescriptor descriptor = smpDescriptorExtractor.extractPluginDescriptor(file);
+      verifyInformation(plugin.getDescriptor(), descriptor);
+
+      PluginInstallationVerifier.verify(context, descriptor);
+
       return new PendingPluginInstallation(plugin.install(), file);
+    } catch (PluginException ex) {
+      cleanup(file);
+      throw ex;
     } catch (IOException ex) {
       cleanup(file);
       throw new PluginDownloadException(plugin, ex);
     }
   }
 
+  private void verifyInformation(AvailablePluginDescriptor descriptorFromPluginCenter, InstalledPluginDescriptor downloadedDescriptor) {
+    verifyInformation(descriptorFromPluginCenter.getInformation(), downloadedDescriptor.getInformation());
+  }
+
+  private void verifyInformation(PluginInformation informationFromPluginCenter, PluginInformation downloadedInformation) {
+    if (!informationFromPluginCenter.getName().equals(downloadedInformation.getName())) {
+      throw new PluginInformationMismatchException(
+        informationFromPluginCenter, downloadedInformation,
+        String.format(
+          "downloaded plugin name \"%s\" does not match the expected name \"%s\" from plugin-center",
+          downloadedInformation.getName(),
+          informationFromPluginCenter.getName()
+        )
+      );
+    }
+    if (!informationFromPluginCenter.getVersion().equals(downloadedInformation.getVersion())) {
+      throw new PluginInformationMismatchException(
+        informationFromPluginCenter, downloadedInformation,
+        String.format(
+          "downloaded plugin version \"%s\" does not match the expected version \"%s\" from plugin-center",
+          downloadedInformation.getVersion(),
+          informationFromPluginCenter.getVersion()
+        )
+      );
+    }
+  }
+
   private void cleanup(Path file) {
     try {
       if (file != null) {
@@ -89,26 +125,12 @@ class PluginInstaller {
     }
   }
 
-  private void verifyConditions(AvailablePlugin plugin, Path file) throws IOException {
-    InstalledPluginDescriptor pluginDescriptor = smpDescriptorExtractor.extractPluginDescriptor(file);
-    if (!pluginDescriptor.getCondition().isSupported()) {
-      cleanup(file);
-      throw new PluginConditionFailedException(
-        pluginDescriptor.getCondition(),
-        String.format(
-          "could not load plugin %s, the plugin condition does not match",
-          plugin.getDescriptor().getInformation().getName()
-        )
-      );
-    }
-  }
-
   private InputStream download(AvailablePlugin plugin) throws IOException {
     return client.get(plugin.getDescriptor().getUrl()).request().contentAsStream();
   }
 
   private Path createFile(AvailablePlugin plugin) throws IOException {
-    Path directory = context.resolve(Paths.get("plugins"));
+    Path directory = scmContext.resolve(Paths.get("plugins"));
     Files.createDirectories(directory);
     return directory.resolve(plugin.getDescriptor().getInformation().getName() + ".smp");
   }

scm-webapp/src/main/java/sonia/scm/plugin/PluginProcessor.java

@@ -21,7 +21,7 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  */
-    
+
 package sonia.scm.plugin;
 
 //~--- non-JDK imports --------------------------------------------------------
@@ -35,7 +35,6 @@ import com.google.common.hash.Hashing;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import sonia.scm.lifecycle.classloading.ClassLoaderLifeCycle;
-import sonia.scm.plugin.ExplodedSmp.PathTransformer;
 
 import javax.xml.bind.JAXBContext;
 import javax.xml.bind.JAXBException;
@@ -50,11 +49,14 @@ import java.nio.file.Path;
 import java.text.SimpleDateFormat;
 import java.util.ArrayList;
 import java.util.Date;
+import java.util.HashMap;
 import java.util.List;
+import java.util.Map;
 import java.util.Set;
 import java.util.function.Predicate;
+import java.util.stream.Collectors;
 
-import static java.util.stream.Collectors.toList;
+import static java.util.stream.Collectors.toSet;
 
 //~--- JDK imports ------------------------------------------------------------
 
@@ -103,6 +105,8 @@ public final class PluginProcessor
 
   //~--- constructors ---------------------------------------------------------
 
+  private final SmpDescriptorExtractor extractor = new SmpDescriptorExtractor();
+
   private ClassLoaderLifeCycle classLoaderLifeCycle;
 
   /**
@@ -162,25 +166,16 @@ public final class PluginProcessor
   {
     logger.info("collect plugins");
 
-    Set<Path> archives = collect(pluginDirectory, new PluginArchiveFilter());
+    Set<ExplodedSmp> installedPlugins = findInstalledPlugins();
+    logger.debug("found {} installed plugins", installedPlugins.size());
 
-    logger.debug("extract {} archives", archives.size());
+    Set<ExplodedSmp> newlyInstalledPlugins = installPending(installedPlugins);
+    logger.debug("finished installation of {} plugins", newlyInstalledPlugins.size());
 
-    extract(archives);
+    Set<ExplodedSmp> plugins = concat(installedPlugins, newlyInstalledPlugins);
-
-    List<Path> dirs =
-      collectPluginDirectories(pluginDirectory)
-      .stream()
-      .filter(isPluginDirectory())
-      .collect(toList());
-
-    logger.debug("process {} directories: {}", dirs.size(), dirs);
-
-    List<ExplodedSmp> smps = Lists.transform(dirs, new PathTransformer());
 
     logger.trace("start building plugin tree");
-
+    PluginTree pluginTree = new PluginTree(plugins);
-    PluginTree pluginTree = new PluginTree(smps);
 
     logger.info("install plugin tree:\n{}", pluginTree);
 
@@ -195,6 +190,52 @@ public final class PluginProcessor
     return ImmutableSet.copyOf(wrappers);
   }
 
+  private Set<ExplodedSmp> concat(Set<ExplodedSmp> installedPlugins, Set<ExplodedSmp> newlyInstalledPlugins) {
+    // We first add all newly installed plugins,
+    // after that we add the missing plugins, which are already installed.
+    // ExplodedSmp is equal by its path, so duplicates (updates) are not in the result.
+    return ImmutableSet.<ExplodedSmp>builder()
+      .addAll(newlyInstalledPlugins)
+      .addAll(installedPlugins)
+      .build();
+  }
+
+  private Set<ExplodedSmp> installPending(Set<ExplodedSmp> installedPlugins) throws IOException {
+    Set<Path> archives = collect(pluginDirectory, new PluginArchiveFilter());
+    logger.debug("start installation of {} pending archives", archives.size());
+
+    Map<Path, InstalledPluginDescriptor> pending = new HashMap<>();
+    for (Path archive : archives) {
+      pending.put(archive, extractor.extractPluginDescriptor(archive));
+    }
+
+    PluginInstallationContext installationContext = PluginInstallationContext.fromDescriptors(
+      installedPlugins.stream().map(ExplodedSmp::getPlugin).collect(toSet()),
+      pending.values()
+    );
+
+    for (Map.Entry<Path, InstalledPluginDescriptor> entry : pending.entrySet()) {
+      try {
+        PluginInstallationVerifier.verify(installationContext, entry.getValue());
+      } catch (PluginException ex) {
+        Path path = entry.getKey();
+        logger.error("failed to install smp {}, because it could not be verified", path);
+        logger.error("to restore scm-manager functionality remove the smp file {} from the plugin directory", path);
+        throw ex;
+      }
+    }
+
+    return extract(archives);
+  }
+
+  private Set<ExplodedSmp> findInstalledPlugins() throws IOException {
+    return collectPluginDirectories(pluginDirectory)
+      .stream()
+      .filter(isPluginDirectory())
+      .map(ExplodedSmp::create)
+      .collect(Collectors.toSet());
+  }
+
   private Predicate<Path> isPluginDirectory() {
     return dir -> Files.exists(dir.resolve(DIRECTORY_METAINF).resolve("scm").resolve("plugin.xml"));
   }
@@ -505,10 +546,12 @@ public final class PluginProcessor
    *
    * @throws IOException
    */
-  private void extract(Iterable<Path> archives) throws IOException
+  private Set<ExplodedSmp> extract(Iterable<Path> archives) throws IOException
   {
     logger.debug("extract archives");
 
+    ImmutableSet.Builder<ExplodedSmp> extracted = ImmutableSet.builder();
+
     for (Path archive : archives)
     {
       File archiveFile = archive.toFile();
@@ -519,17 +562,18 @@ public final class PluginProcessor
 
       logger.debug("extract plugin {}", smp.getPlugin());
 
-      File directory =
+      File directory = PluginsInternal.createPluginDirectory(pluginDirectory.toFile(), smp.getPlugin());
-        PluginsInternal.createPluginDirectory(pluginDirectory.toFile(),
-          smp.getPlugin());
 
-      String checksum = com.google.common.io.Files.hash(archiveFile,
+      String checksum = com.google.common.io.Files.hash(archiveFile, Hashing.sha256()).toString();
-                          Hashing.sha256()).toString();
       File checksumFile = PluginsInternal.getChecksumFile(directory);
 
       PluginsInternal.extract(smp, checksum, directory, checksumFile, false);
       moveArchive(archive);
+
+      extracted.add(ExplodedSmp.create(directory.toPath()));
     }
+
+    return extracted.build();
   }
 
   /**

scm-webapp/src/main/java/sonia/scm/plugin/PluginTree.java

@@ -21,7 +21,7 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  */
-    
+
 package sonia.scm.plugin;
 
 //~--- non-JDK imports --------------------------------------------------------
@@ -30,6 +30,7 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.util.Arrays;
+import java.util.Collection;
 import java.util.LinkedHashSet;
 import java.util.LinkedList;
 import java.util.List;
@@ -71,7 +72,7 @@ public final class PluginTree
    *
    * @param smps
    */
-  public PluginTree(List<ExplodedSmp> smps)
+  public PluginTree(Collection<ExplodedSmp> smps)
   {
 
     smps.forEach(s -> {
@@ -155,7 +156,8 @@ public final class PluginTree
   }
 
   private void append(StringBuilder buffer, String indent, PluginNode node) {
-    buffer.append(indent).append("+- ").append(node.getId()).append("\n");
+    PluginInformation information = node.getPlugin().getPlugin().getInformation();
+    buffer.append(indent).append("+- ").append(node.getId()).append("@").append(information.getVersion()).append("\n");
     for (PluginNode child : node.getChildren()) {
       append(buffer, indent + "   ", child);
     }

scm-webapp/src/main/java/sonia/scm/plugin/SmpDescriptorExtractor.java

@@ -21,7 +21,7 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  */
-    
+
 package sonia.scm.plugin;
 
 import javax.xml.bind.JAXBContext;
@@ -36,7 +36,7 @@ import java.util.zip.ZipInputStream;
 class SmpDescriptorExtractor {
 
   InstalledPluginDescriptor extractPluginDescriptor(Path file) throws IOException {
-    try (ZipInputStream zipInputStream = new ZipInputStream(Files.newInputStream(file), StandardCharsets.UTF_8))    {
+    try (ZipInputStream zipInputStream = new ZipInputStream(Files.newInputStream(file), StandardCharsets.UTF_8)) {
       ZipEntry nextEntry;
       while ((nextEntry = zipInputStream.getNextEntry()) != null) {
         if ("META-INF/scm/plugin.xml".equals(nextEntry.getName())) {

scm-webapp/src/main/resources/locales/de/plugins.json

@@ -241,6 +241,18 @@
       "displayName": "Fehler beim Löschen falscher Downloads",
       "description": "Ein fehlerhaft heruntergeladenes Plugin konnte nicht gelöscht werden. Bitte prüfen Sie die Server Logs und löschen die Datei manuell."
     },
+    "5GS6lwvWF1": {
+      "displayName": "Abhänigkeit konnte nicht gefunden werden",
+      "description": "Eine der Abhänigkeiten des Plugins konnte nicht gefunden werden. Bitte prüfen Sie die Logs für weitere Informationen."
+    },
+    "E5S6niWwi1": {
+      "displayName": "Version einer Abhänigkeit zu niedrig",
+      "description": "Die Version einer Abhänigkeit des Plugin ist zu niedrig. Bitte prüfen Sie die Logs für weitere Informationen."
+    },
+    "4RS6niPRX1": {
+      "displayName": "Plugin information stimmen nicht überein",
+      "description": "Die Informationen des heruntergeladenen Plugins stimmen nicht mit den Informationen des Plugin Centers überein. Bitte prüfen Sie die Logs für weitere Informationen."
+    },
     "2qRyyaVcJ1": {
       "displayName": "Ungültig formatiertes Element",
       "description": "Die Eingabe beinhaltete unfültige Formate. Bitte prüfen Sie die Server Logs für genauere Informationen."

scm-webapp/src/main/resources/locales/en/plugins.json

@@ -241,6 +241,18 @@
       "displayName": "Error while cleaning up failed plugin",
       "description": "A failed plugin download could not be removed correctly. Please check the server log and remove the plugin manually."
     },
+    "5GS6lwvWF1": {
+      "displayName": "Dependency not found",
+      "description": "One of the plugin dependencies could not be found. Please check the server logs for more details."
+    },
+    "E5S6niWwi1": {
+      "displayName": "Dependency version mismatch",
+      "description": "The plugin depends on a newer version of an already installed plugin. Please check the server logs for more details."
+    },
+    "4RS6niPRX1": {
+      "displayName": "Plugin information mismatch",
+      "description": "The downloaded plugin does not match the information provided by the plugin center. Please check the server logs for more details."
+    },
     "2qRyyaVcJ1": {
       "displayName": "Invalid format in element",
       "description": "The input had some invalid formats. Please check the server log for further information."

scm-webapp/src/test/java/sonia/scm/plugin/DefaultPluginManagerTest.java

@@ -90,20 +90,28 @@ class DefaultPluginManagerTest {
   @Captor
   private ArgumentCaptor<PluginEvent> eventCaptor;
 
-  @InjectMocks
   private DefaultPluginManager manager;
 
   @Mock
   private Subject subject;
 
+  private final PluginInstallationContext context = PluginInstallationContext.empty();
+
   @BeforeEach
   void mockInstaller() {
-    lenient().when(installer.install(any())).then(ic -> {
+    lenient().when(installer.install(any(), any())).then(ic -> {
-      AvailablePlugin plugin = ic.getArgument(0);
+      AvailablePlugin plugin = ic.getArgument(1);
       return new PendingPluginInstallation(plugin.install(), null);
     });
   }
 
+  @BeforeEach
+  void setUpObjectUnderTest() {
+    manager = new DefaultPluginManager(
+      loader, center, installer, restarter, eventBus, plugins -> context
+    );
+  }
+
   @Nested
   class WithAdminPermissions {
 
@@ -209,7 +217,7 @@ class DefaultPluginManagerTest {
 
       manager.install("scm-git-plugin", false);
 
-      verify(installer).install(git);
+      verify(installer).install(context, git);
       verify(restarter, never()).restart(any(), any());
     }
 
@@ -222,8 +230,8 @@ class DefaultPluginManagerTest {
 
       manager.install("scm-review-plugin", false);
 
-      verify(installer).install(mail);
+      verify(installer).install(context, mail);
-      verify(installer).install(review);
+      verify(installer).install(context, review);
     }
 
     @Test
@@ -239,7 +247,7 @@ class DefaultPluginManagerTest {
       manager.install("scm-review-plugin", false);
 
       ArgumentCaptor<AvailablePlugin> captor = ArgumentCaptor.forClass(AvailablePlugin.class);
-      verify(installer).install(captor.capture());
+      verify(installer).install(any(), captor.capture());
 
       assertThat(captor.getValue().getDescriptor().getInformation().getName()).isEqualTo("scm-review-plugin");
     }
@@ -256,8 +264,8 @@ class DefaultPluginManagerTest {
 
       manager.install("scm-review-plugin", false);
 
-      verify(installer).install(mail);
+      verify(installer).install(context, mail);
-      verify(installer).install(review);
+      verify(installer).install(context, review);
     }
 
     @Test
@@ -272,8 +280,8 @@ class DefaultPluginManagerTest {
 
       manager.install("scm-review-plugin", false);
 
-      verify(installer).install(mail);
+      verify(installer).install(context, mail);
-      verify(installer).install(review);
+      verify(installer).install(context, review);
     }
 
     @Test
@@ -285,8 +293,8 @@ class DefaultPluginManagerTest {
 
       manager.install("scm-review-plugin", false);
 
-      verify(installer, never()).install(mail);
+      verify(installer, never()).install(context, mail);
-      verify(installer).install(review);
+      verify(installer).install(context, review);
     }
 
     @Test
@@ -299,12 +307,12 @@ class DefaultPluginManagerTest {
       when(center.getAvailable()).thenReturn(ImmutableSet.of(review, mail, notification));
 
       PendingPluginInstallation pendingNotification = mock(PendingPluginInstallation.class);
-      doReturn(pendingNotification).when(installer).install(notification);
+      doReturn(pendingNotification).when(installer).install(context, notification);
 
       PendingPluginInstallation pendingMail = mock(PendingPluginInstallation.class);
-      doReturn(pendingMail).when(installer).install(mail);
+      doReturn(pendingMail).when(installer).install(context, mail);
 
-      doThrow(new PluginChecksumMismatchException(mail, "1", "2")).when(installer).install(review);
+      doThrow(new PluginChecksumMismatchException(mail, "1", "2")).when(installer).install(context, review);
 
       assertThrows(PluginInstallException.class, () -> manager.install("scm-review-plugin", false));
 
@@ -322,7 +330,7 @@ class DefaultPluginManagerTest {
 
       assertThrows(NotFoundException.class, () -> manager.install("scm-review-plugin", false));
 
-      verify(installer, never()).install(any());
+      verify(installer, never()).install(any(), any());
     }
 
     @Test
@@ -332,7 +340,7 @@ class DefaultPluginManagerTest {
 
       manager.install("scm-git-plugin", true);
 
-      verify(installer).install(git);
+      verify(installer).install(context, git);
       verify(restarter).restart(any(), any());
     }
 
@@ -353,7 +361,7 @@ class DefaultPluginManagerTest {
       manager.install("scm-review-plugin", false);
       manager.install("scm-review-plugin", false);
       // only one interaction
-      verify(installer).install(any());
+      verify(installer).install(any(), any());
     }
 
     @Test
@@ -538,7 +546,7 @@ class DefaultPluginManagerTest {
       AvailablePlugin git = createAvailable("scm-git-plugin");
       when(center.getAvailable()).thenReturn(ImmutableSet.of(git));
       PendingPluginInstallation gitPendingPluginInformation = mock(PendingPluginInstallation.class);
-      when(installer.install(git)).thenReturn(gitPendingPluginInformation);
+      when(installer.install(context, git)).thenReturn(gitPendingPluginInformation);
 
       manager.install("scm-git-plugin", false);
       manager.uninstall("scm-ssh-plugin", false);
@@ -571,8 +579,8 @@ class DefaultPluginManagerTest {
 
       manager.updateAll();
 
-      verify(installer).install(newMailPlugin);
+      verify(installer).install(context, newMailPlugin);
-      verify(installer).install(newReviewPlugin);
+      verify(installer).install(context, newReviewPlugin);
     }
 
 
@@ -587,7 +595,7 @@ class DefaultPluginManagerTest {
 
       manager.updateAll();
 
-      verify(installer, never()).install(oldScriptPlugin);
+      verify(installer, never()).install(context, oldScriptPlugin);
     }
 
     @Test
@@ -607,7 +615,7 @@ class DefaultPluginManagerTest {
     void shouldFirePluginEventOnFailedInstallation() {
       AvailablePlugin review = createAvailable("scm-review-plugin");
       when(center.getAvailable()).thenReturn(ImmutableSet.of(review));
-      doThrow(new PluginDownloadException(review, new IOException())).when(installer).install(review);
+      doThrow(new PluginDownloadException(review, new IOException())).when(installer).install(context, review);
 
       assertThrows(PluginDownloadException.class, () -> manager.install("scm-review-plugin", false));
 

scm-webapp/src/test/java/sonia/scm/plugin/PluginInstallationContextTest.java

@@ -0,0 +1,115 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020-present Cloudogu GmbH and Contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package sonia.scm.plugin;
+
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Answers;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import java.util.Collections;
+import java.util.Optional;
+import java.util.Set;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+@ExtendWith(MockitoExtension.class)
+class PluginInstallationContextTest {
+
+  @Test
+  void shouldReturnInstalledPlugin() {
+    Set<InstalledPlugin> installed = installed("scm-git-plugin", "1.0.0");
+    Set<AvailablePlugin> pending = Collections.emptySet();
+
+    PluginInstallationContext context = PluginInstallationContext.from(installed, pending);
+    Optional<NameAndVersion> plugin = context.find("scm-git-plugin");
+    assertThat(plugin).contains(new NameAndVersion("scm-git-plugin", "1.0.0"));
+  }
+
+  @Test
+  void shouldReturnPendingPlugin() {
+    Set<InstalledPlugin> installed = Collections.emptySet();
+    Set<AvailablePlugin> pending = pending("scm-hg-plugin", "1.0.0");
+
+    PluginInstallationContext context = PluginInstallationContext.from(installed, pending);
+    Optional<NameAndVersion> plugin = context.find("scm-hg-plugin");
+    assertThat(plugin).contains(new NameAndVersion("scm-hg-plugin", "1.0.0"));
+  }
+
+  @Test
+  void shouldReturnPendingEvenWithInstalled() {
+    Set<InstalledPlugin> installed = installed("scm-svn-plugin", "1.1.0");
+    Set<AvailablePlugin> pending = pending("scm-svn-plugin", "1.2.0");
+
+    PluginInstallationContext context = PluginInstallationContext.from(installed, pending);
+    Optional<NameAndVersion> plugin = context.find("scm-svn-plugin");
+    assertThat(plugin).contains(new NameAndVersion("scm-svn-plugin", "1.2.0"));
+  }
+
+  @Test
+  void shouldReturnEmpty() {
+    Set<InstalledPlugin> installed = Collections.emptySet();
+    Set<AvailablePlugin> pending = Collections.emptySet();
+
+    PluginInstallationContext context = PluginInstallationContext.from(installed, pending);
+    Optional<NameAndVersion> plugin = context.find("scm-legacy-plugin");
+    assertThat(plugin).isEmpty();
+  }
+
+  @Test
+  void shouldCreateContextFromDescriptor() {
+    Set<InstalledPluginDescriptor> installed = mockDescriptor(InstalledPluginDescriptor.class, "scm-svn-plugin", "1.1.0");
+    Set<AvailablePluginDescriptor> pending = mockDescriptor(AvailablePluginDescriptor.class, "scm-svn-plugin", "1.2.0");
+
+    PluginInstallationContext context = PluginInstallationContext.fromDescriptors(installed, pending);
+    Optional<NameAndVersion> plugin = context.find("scm-svn-plugin");
+    assertThat(plugin).contains(new NameAndVersion("scm-svn-plugin", "1.2.0"));
+  }
+
+  private Set<InstalledPlugin> installed(String name, String version) {
+    return mockPlugin(InstalledPlugin.class, name, version);
+  }
+
+  private Set<AvailablePlugin> pending(String name, String version) {
+    return mockPlugin(AvailablePlugin.class, name, version);
+  }
+
+  private <P extends Plugin> Set<P> mockPlugin(Class<P> pluginClass, String name, String version) {
+    P plugin = mock(pluginClass, Answers.RETURNS_DEEP_STUBS);
+    when(plugin.getDescriptor().getInformation().getName()).thenReturn(name);
+    when(plugin.getDescriptor().getInformation().getVersion()).thenReturn(version);
+    return Collections.singleton(plugin);
+  }
+
+  private <D extends PluginDescriptor> Set<D> mockDescriptor(Class<D> descriptorClass, String name, String version) {
+    D desc = mock(descriptorClass, Answers.RETURNS_DEEP_STUBS);
+    when(desc.getInformation().getName()).thenReturn(name);
+    when(desc.getInformation().getVersion()).thenReturn(version);
+    return Collections.singleton(desc);
+  }
+
+}

scm-webapp/src/test/java/sonia/scm/plugin/PluginInstallationVerifierTest.java

@@ -0,0 +1,174 @@
+/*
+ * MIT License
+ *
+ * Copyright (c) 2020-present Cloudogu GmbH and Contributors
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+package sonia.scm.plugin;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Answers;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import java.util.Collections;
+import java.util.Optional;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+import static sonia.scm.plugin.PluginInstallationContext.empty;
+
+@ExtendWith(MockitoExtension.class)
+class PluginInstallationVerifierTest {
+
+  @Mock(answer = Answers.RETURNS_DEEP_STUBS)
+  private InstalledPluginDescriptor descriptor;
+
+  // hog stands for "Heart of Gold"
+  private static final String HOG_PLUGIN = "scm-hog-plugin";
+
+  // iid stands for "Infinite Improbability Drive"
+  private static final String IID_PLUGIN = "scm-iid-plugin";
+
+  @BeforeEach
+  void setUpDescriptor() {
+    PluginInformation information = new PluginInformation();
+    information.setName(HOG_PLUGIN);
+    information.setVersion("1.0.0");
+    when(descriptor.getInformation()).thenReturn(information);
+  }
+
+  @Test
+  void shouldFailOnCondition() {
+    PluginInstallationContext context = empty();
+    assertThrows(PluginConditionFailedException.class, () -> PluginInstallationVerifier.verify(context, descriptor));
+  }
+
+  @Test
+  void shouldFailOnMissingDependency() {
+    matchConditions();
+    when(descriptor.getDependenciesWithVersion()).thenReturn(Collections.singleton(new NameAndVersion(IID_PLUGIN)));
+    PluginInstallationContext context = empty();
+
+    DependencyNotFoundException exception = assertThrows(
+      DependencyNotFoundException.class, () -> PluginInstallationVerifier.verify(context, descriptor)
+    );
+    assertThat(exception.getPlugin()).isEqualTo(HOG_PLUGIN);
+    assertThat(exception.getMissingDependency()).isEqualTo(IID_PLUGIN);
+  }
+
+  private void matchConditions() {
+    when(descriptor.getCondition().isSupported()).thenReturn(true);
+  }
+
+  @Test
+  void shouldFailOnDependencyVersionMismatch() {
+    matchConditions();
+
+    // mock installation of iid 1.0.0
+    PluginInstallationContext context = mockInstallationOf(IID_PLUGIN, "1.0.0");
+
+    // mock dependency of iid 1.1.0
+    mockDependingOf(IID_PLUGIN, "1.1.0");
+
+    DependencyVersionMismatchException exception = assertThrows(
+      DependencyVersionMismatchException.class, () -> PluginInstallationVerifier.verify(context, descriptor)
+    );
+    assertThat(exception.getPlugin()).isEqualTo(HOG_PLUGIN);
+    assertThat(exception.getDependency()).isEqualTo(IID_PLUGIN);
+    assertThat(exception.getMinVersion()).isEqualTo("1.1.0");
+    assertThat(exception.getCurrentVersion()).isEqualTo("1.0.0");
+  }
+
+  @Test
+  void shouldFailOnOptionalDependencyVersionMismatch() {
+    matchConditions();
+
+    // mock installation of iid 1.0.0
+    PluginInstallationContext context = mockInstallationOf(IID_PLUGIN, "1.0.0");
+
+    // mock dependency of iid 1.1.0
+    mockOptionalDependingOf(IID_PLUGIN, "1.1.0");
+
+    DependencyVersionMismatchException exception = assertThrows(
+      DependencyVersionMismatchException.class, () -> PluginInstallationVerifier.verify(context, descriptor)
+    );
+    assertThat(exception.getPlugin()).isEqualTo(HOG_PLUGIN);
+    assertThat(exception.getDependency()).isEqualTo(IID_PLUGIN);
+    assertThat(exception.getMinVersion()).isEqualTo("1.1.0");
+    assertThat(exception.getCurrentVersion()).isEqualTo("1.0.0");
+  }
+
+  @Test
+  @SuppressWarnings("squid:S2699") // we are happy if no exception is thrown
+  void shouldVerifyPlugin() {
+    matchConditions();
+
+    PluginInstallationContext context = empty();
+    PluginInstallationVerifier.verify(context, descriptor);
+  }
+
+  @Test
+  @SuppressWarnings("squid:S2699") // we are happy if no exception is thrown
+  void shouldVerifyPluginWithDependencies() {
+    matchConditions();
+
+    // mock installation of iid 1.1.0
+    PluginInstallationContext context = mockInstallationOf(IID_PLUGIN, "1.1.0");
+
+    // mock dependency of iid 1.1.0
+    mockDependingOf(IID_PLUGIN, "1.1.0");
+
+    PluginInstallationVerifier.verify(context, descriptor);
+  }
+
+  @Test
+  @SuppressWarnings("squid:S2699") // we are happy if no exception is thrown
+  void shouldVerifyPluginWithOptionalDependency() {
+    matchConditions();
+
+    PluginInstallationContext context = PluginInstallationContext.empty();
+
+    // mock dependency of iid 1.1.0
+    mockOptionalDependingOf(IID_PLUGIN, "1.1.0");
+
+    PluginInstallationVerifier.verify(context, descriptor);
+  }
+
+  private void mockOptionalDependingOf(String plugin, String version) {
+    when(descriptor.getOptionalDependenciesWithVersion()).thenReturn(Collections.singleton(new NameAndVersion(plugin, version)));
+  }
+
+  private void mockDependingOf(String plugin, String version) {
+    when(descriptor.getDependenciesWithVersion()).thenReturn(Collections.singleton(new NameAndVersion(plugin, version)));
+  }
+
+  private PluginInstallationContext mockInstallationOf(String plugin, String version) {
+    PluginInstallationContext context = mock(PluginInstallationContext.class);
+    when(context.find(IID_PLUGIN)).thenReturn(Optional.of(new NameAndVersion(plugin, version)));
+    return context;
+  }
+
+}

scm-webapp/src/test/java/sonia/scm/plugin/PluginInstallerTest.java

@@ -83,7 +83,7 @@ class PluginInstallerTest {
   void shouldDownloadPlugin() throws IOException {
     mockContent("42");
 
-    installer.install(createGitPlugin());
+    installer.install(PluginInstallationContext.empty(), createGitPlugin());
 
     assertThat(directory.resolve("plugins").resolve("scm-git-plugin.smp")).hasContent("42");
   }
@@ -93,7 +93,7 @@ class PluginInstallerTest {
     mockContent("42");
     AvailablePlugin gitPlugin = createGitPlugin();
 
-    PendingPluginInstallation pending = installer.install(gitPlugin);
+    PendingPluginInstallation pending = installer.install(PluginInstallationContext.empty(), gitPlugin);
 
     assertThat(pending).isNotNull();
     assertThat(pending.getPlugin().getDescriptor()).isEqualTo(gitPlugin.getDescriptor());
@@ -117,14 +117,18 @@ class PluginInstallerTest {
   void shouldThrowPluginDownloadException() throws IOException {
     when(client.get("https://download.hitchhiker.com").request()).thenThrow(new IOException("failed to download"));
 
-    assertThrows(PluginDownloadException.class, () -> installer.install(createGitPlugin()));
+    PluginInstallationContext context = PluginInstallationContext.empty();
+    AvailablePlugin gitPlugin = createGitPlugin();
+    assertThrows(PluginDownloadException.class, () -> installer.install(context, gitPlugin));
   }
 
   @Test
   void shouldThrowPluginChecksumMismatchException() throws IOException {
     mockContent("21");
 
-    assertThrows(PluginChecksumMismatchException.class, () -> installer.install(createGitPlugin()));
+    PluginInstallationContext context = PluginInstallationContext.empty();
+    AvailablePlugin gitPlugin = createGitPlugin();
+    assertThrows(PluginChecksumMismatchException.class, () -> installer.install(context, gitPlugin));
     assertThat(directory.resolve("plugins").resolve("scm-git-plugin.smp")).doesNotExist();
   }
 
@@ -134,7 +138,9 @@ class PluginInstallerTest {
     when(stream.read(any(), anyInt(), anyInt())).thenThrow(new IOException("failed to read"));
     when(client.get("https://download.hitchhiker.com").request().contentAsStream()).thenReturn(stream);
 
-    assertThrows(PluginDownloadException.class, () -> installer.install(createGitPlugin()));
+    PluginInstallationContext context = PluginInstallationContext.empty();
+    AvailablePlugin gitPlugin = createGitPlugin();
+    assertThrows(PluginDownloadException.class, () -> installer.install(context, gitPlugin));
     assertThat(directory.resolve("plugins").resolve("scm-git-plugin.smp")).doesNotExist();
   }
 
@@ -144,13 +150,44 @@ class PluginInstallerTest {
     InstalledPluginDescriptor supportedPlugin = createPluginDescriptor(false);
     when(extractor.extractPluginDescriptor(any())).thenReturn(supportedPlugin);
 
-    assertThrows(PluginConditionFailedException.class, () -> installer.install(createGitPlugin()));
+    PluginInstallationContext context = PluginInstallationContext.empty();
+    AvailablePlugin gitPlugin = createGitPlugin();
+    assertThrows(PluginConditionFailedException.class, () -> installer.install(context, gitPlugin));
     assertThat(directory.resolve("plugins").resolve("scm-git-plugin.smp")).doesNotExist();
   }
 
+  @Test
+  void shouldFailForNameMismatch() throws IOException {
+    mockContent("42");
+
+    InstalledPluginDescriptor supportedPlugin = createPluginDescriptor("scm-svn-plugin", "1.0.0", true);
+    when(extractor.extractPluginDescriptor(any())).thenReturn(supportedPlugin);
+
+    PluginInstallationContext context = PluginInstallationContext.empty();
+    AvailablePlugin gitPlugin = createGitPlugin();
+    PluginInformationMismatchException exception = assertThrows(PluginInformationMismatchException.class, () -> installer.install(context, gitPlugin));
+    assertThat(exception.getApi().getName()).isEqualTo("scm-git-plugin");
+    assertThat(exception.getDownloaded().getName()).isEqualTo("scm-svn-plugin");
+  }
+
+  @Test
+  void shouldFailForVersionMismatch() throws IOException {
+    mockContent("42");
+
+    InstalledPluginDescriptor supportedPlugin = createPluginDescriptor("scm-git-plugin", "1.1.0", true);
+    when(extractor.extractPluginDescriptor(any())).thenReturn(supportedPlugin);
+
+    PluginInstallationContext context = PluginInstallationContext.empty();
+    AvailablePlugin gitPlugin = createGitPlugin();
+    PluginInformationMismatchException exception = assertThrows(PluginInformationMismatchException.class, () -> installer.install(context, gitPlugin));
+    assertThat(exception.getApi().getVersion()).isEqualTo("1.0.0");
+    assertThat(exception.getDownloaded().getVersion()).isEqualTo("1.1.0");
+  }
+
   private AvailablePlugin createPlugin(String name, String url, String checksum) {
     PluginInformation information = new PluginInformation();
     information.setName(name);
+    information.setVersion("1.0.0");
     AvailablePluginDescriptor descriptor = new AvailablePluginDescriptor(
       information, null, Collections.emptySet(), url, checksum
     );
@@ -158,9 +195,15 @@ class PluginInstallerTest {
   }
 
   private InstalledPluginDescriptor createPluginDescriptor(boolean supported) {
+    return createPluginDescriptor("scm-git-plugin", "1.0.0", supported);
+  }
+
+  private InstalledPluginDescriptor createPluginDescriptor(String name, String version, boolean supported) {
     InstalledPluginDescriptor installedPluginDescriptor = mock(InstalledPluginDescriptor.class, RETURNS_DEEP_STUBS);
+    lenient().when(installedPluginDescriptor.getInformation().getId()).thenReturn(name);
+    lenient().when(installedPluginDescriptor.getInformation().getName()).thenReturn(name);
+    lenient().when(installedPluginDescriptor.getInformation().getVersion()).thenReturn(version);
     lenient().when(installedPluginDescriptor.getCondition().isSupported()).thenReturn(supported);
-    lenient().when(installedPluginDescriptor.getInformation().getId()).thenReturn("scm-git-plugin");
     return installedPluginDescriptor;
   }
 }

scm-webapp/src/test/java/sonia/scm/plugin/PluginProcessorTest.java

@@ -21,164 +21,182 @@
  * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  */
-    
+
 package sonia.scm.plugin;
 
 //~--- non-JDK imports --------------------------------------------------------
 
 import com.google.common.base.Charsets;
-import com.google.common.base.Predicate;
 import com.google.common.collect.Iterables;
 import com.google.common.io.Resources;
-
+import org.junit.jupiter.api.BeforeEach;
-import org.junit.Before;
+import org.junit.jupiter.api.Test;
-import org.junit.Rule;
+import org.junit.jupiter.api.io.TempDir;
-import org.junit.Test;
-import org.junit.rules.TemporaryFolder;
 import sonia.scm.lifecycle.classloading.ClassLoaderLifeCycle;
 
-import static org.hamcrest.Matchers.*;
+import javax.xml.bind.JAXB;
-
-import static org.junit.Assert.*;
-
-//~--- JDK imports ------------------------------------------------------------
-
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
-
-import java.lang.reflect.InvocationTargetException;
-
 import java.net.URL;
-
+import java.nio.file.Path;
 import java.util.Set;
+import java.util.stream.Collectors;
+import java.util.zip.ZipEntry;
+import java.util.zip.ZipOutputStream;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 /**
  *
  * @author Sebastian Sdorra
  */
-public class PluginProcessorTest
+class PluginProcessorTest {
-{
 
-  /** Field description */
   private static final PluginResource PLUGIN_A =
     new PluginResource("sonia/scm/plugin/scm-a-plugin.smp", "scm-a-plugin.smp",
       "scm-a-plugin:1.0.0-SNAPSHOT");
 
-  /** Field description */
   private static final PluginResource PLUGIN_B =
     new PluginResource("sonia/scm/plugin/scm-b-plugin.smp", "scm-b-plugin.smp",
       "scm-b-plugin:1.0.0-SNAPSHOT");
 
-  /** Field description */
   private static final PluginResource PLUGIN_C =
     new PluginResource("sonia/scm/plugin/scm-c-plugin.smp", "scm-c-plugin.smp",
       "scm-c-plugin:1.0.0-SNAPSHOT");
 
-  /** Field description */
   private static final PluginResource PLUGIN_D =
     new PluginResource("sonia/scm/plugin/scm-d-plugin.smp", "scm-d-plugin.smp",
       "scm-d-plugin:1.0.0-SNAPSHOT");
 
-  /** Field description */
   private static final PluginResource PLUGIN_E =
     new PluginResource("sonia/scm/plugin/scm-e-plugin.smp", "scm-e-plugin.smp",
       "scm-e-plugin:1.0.0-SNAPSHOT");
 
-  /** Field description */
   private static final PluginResource PLUGIN_F_1_0_0 =
     new PluginResource("sonia/scm/plugin/scm-f-plugin-1.0.0.smp",
       "scm-f-plugin.smp", "scm-f-plugin:1.0.0");
 
-  /** Field description */
   private static final PluginResource PLUGIN_F_1_0_1 =
     new PluginResource("sonia/scm/plugin/scm-f-plugin-1.0.1.smp",
       "scm-f-plugin.smp", "scm-f-plugin:1.0.1");
 
-  //~--- methods --------------------------------------------------------------
+  private static final String PLUGIN_G = "scm-g-plugin";
+  private static final String PLUGIN_H = "scm-h-plugin";
+  private static final String PLUGIN_I = "scm-i-plugin";
 
-  /**
+  private File pluginDirectory;
-   * Method description
+  private PluginProcessor processor;
-   *
+
-   *
+  @BeforeEach
-   * @throws IOException
+  void setUp(@TempDir Path tempDirectoryPath) {
-   */
+    pluginDirectory = tempDirectoryPath.toFile();
-  @Test(expected = PluginCircularDependencyException.class)
+    processor = new PluginProcessor(ClassLoaderLifeCycle.create(), tempDirectoryPath);
-  public void testCircularDependencies() throws IOException
+  }
-  {
+
+
+  @Test
+  void shouldFailOnPluginCondition() throws IOException {
+    createPendingPluginInstallation(PLUGIN_G);
+
+    assertThrows(PluginConditionFailedException.class, this::collectPlugins);
+  }
+
+
+  @Test
+  void shouldFailOnWrongDependencyVersion() throws IOException {
+    createPendingPluginInstallation(PLUGIN_H);
+    createPendingPluginInstallation(PLUGIN_I);
+    assertThrows(DependencyVersionMismatchException.class, this::collectPlugins);
+  }
+
+  @Test
+  void shouldNotContainDuplicatesOnUpdate() throws IOException {
+    createInstalledPlugin("scm-mail-plugin-2-0-0");
+    createInstalledPlugin("scm-review-plugin-2-0-0");
+    createPendingPluginInstallation("scm-mail-plugin-2-1-0");
+    createPendingPluginInstallation("scm-review-plugin-2-1-0");
+
+    Set<String> plugins = collectPlugins().stream()
+      .map(p -> p.getDescriptor().getInformation().getName(true))
+      .collect(Collectors.toSet());
+    assertThat(plugins).containsOnly("scm-mail-plugin:2.1.0", "scm-review-plugin:2.1.0");
+  }
+
+  @SuppressWarnings("UnstableApiUsage")
+  private void createPendingPluginInstallation(String descriptorResource) throws IOException {
+    URL resource = resource(descriptorResource);
+    InstalledPluginDescriptor descriptor = JAXB.unmarshal(resource, InstalledPluginDescriptor.class);
+
+    File file = new File(pluginDirectory, descriptor.getInformation().getName() + ".smp");
+
+    try (ZipOutputStream zip = new ZipOutputStream(new FileOutputStream(file))) {
+      zip.putNextEntry(new ZipEntry("META-INF/scm/plugin.xml"));
+      Resources.copy(resource, zip);
+    }
+  }
+
+  @SuppressWarnings("UnstableApiUsage")
+  private void createInstalledPlugin(String descriptorResource) throws IOException {
+    URL resource = resource(descriptorResource);
+    InstalledPluginDescriptor descriptor = JAXB.unmarshal(resource, InstalledPluginDescriptor.class);
+
+    File directory = new File(pluginDirectory, descriptor.getInformation().getName());
+    File scmDirectory = new File(directory, "META-INF" + File.separator + "scm");
+    assertThat(scmDirectory.mkdirs()).isTrue();
+
+    try (OutputStream output = new FileOutputStream(new File(scmDirectory, "plugin.xml"))) {
+      Resources.copy(resource, output);
+    }
+  }
+
+  @SuppressWarnings("UnstableApiUsage")
+  private URL resource(String descriptorResource) {
+    return Resources.getResource("sonia/scm/plugin/" + descriptorResource + ".xml");
+  }
+
+  @Test
+  void shouldFailOnCircularDependencies() throws IOException {
     copySmps(PLUGIN_C, PLUGIN_D, PLUGIN_E);
-    collectPlugins();
+    assertThrows(PluginCircularDependencyException.class, this::collectPlugins);
   }
 
-  /**
-   * Method description
-   *
-   *
-   * @throws IOException
-   */
   @Test
-  public void testCollectPlugins() throws IOException
+  void shouldCollectPlugins() throws IOException {
-  {
     copySmp(PLUGIN_A);
 
     InstalledPlugin plugin = collectAndGetFirst();
-
+    assertThat(plugin.getId()).isEqualTo(PLUGIN_A.id);
-    assertThat(plugin.getId(), is(PLUGIN_A.id));
   }
 
   @Test
-  public void shouldCollectPluginsAndDoNotFailOnNonPluginDirectories() throws IOException {
+  void shouldCollectPluginsAndDoNotFailOnNonPluginDirectories() throws IOException {
-    new File(pluginDirectory, "some-directory").mkdirs();
+    assertThat(new File(pluginDirectory, "some-directory").mkdirs()).isTrue();
 
     copySmp(PLUGIN_A);
     InstalledPlugin plugin = collectAndGetFirst();
 
-    assertThat(plugin.getId(), is(PLUGIN_A.id));
+    assertThat(plugin.getId()).isEqualTo(PLUGIN_A.id);
   }
 
-  /**
-   * Method description
-   *
-   *
-   * @throws IOException
-   */
   @Test
-  public void testCollectPluginsWithDependencies() throws IOException
+  void shouldCollectPluginsWithDependencies() throws IOException {
-  {
     copySmps(PLUGIN_A, PLUGIN_B);
 
     Set<InstalledPlugin> plugins = collectPlugins();
-
+    assertThat(plugins).hasSize(2);
-    assertThat(plugins, hasSize(2));
 
     InstalledPlugin a = findPlugin(plugins, PLUGIN_A.id);
-
+    assertThat(a).isNotNull();
-    assertNotNull(a);
 
     InstalledPlugin b = findPlugin(plugins, PLUGIN_B.id);
-
+    assertThat(b).isNotNull();
-    assertNotNull(b);
   }
 
-  /**
-   * Method description
-   *
-   *
-   * @throws ClassNotFoundException
-   * @throws IOException
-   * @throws IllegalAccessException
-   * @throws IllegalArgumentException
-   * @throws InstantiationException
-   * @throws InvocationTargetException
-   * @throws NoSuchMethodException
-   */
   @Test
-  public void testPluginClassLoader()
+  void shouldCreateWorkingPluginClassLoader() throws Exception {
-    throws IOException, ClassNotFoundException, InstantiationException,
-    IllegalAccessException, NoSuchMethodException, IllegalArgumentException,
-    InvocationTargetException
-  {
     copySmp(PLUGIN_A);
 
     InstalledPlugin plugin = collectAndGetFirst();
@@ -187,36 +205,20 @@ public class PluginProcessorTest
     // load parent class
     Class<?> clazz = cl.loadClass(PluginResource.class.getName());
 
-    assertSame(PluginResource.class, clazz);
+    assertThat(PluginResource.class).isSameAs(clazz);
 
     // load packaged class
     clazz = cl.loadClass("sonia.scm.plugins.HelloService");
-    assertNotNull(clazz);
+    assertThat(clazz).isNotNull();
 
     Object instance = clazz.newInstance();
     Object result = clazz.getMethod("sayHello").invoke(instance);
 
-    assertEquals("hello", result);
+    assertThat(result).isEqualTo("hello");
   }
 
-  /**
-   * Method description
-   *
-   *
-   * @throws ClassNotFoundException
-   * @throws IOException
-   * @throws IllegalAccessException
-   * @throws IllegalArgumentException
-   * @throws InstantiationException
-   * @throws InvocationTargetException
-   * @throws NoSuchMethodException
-   */
   @Test
-  public void testPluginClassLoaderWithDependencies()
+  void shouldCreateWorkingPluginClassLoaderWithDependencies() throws Exception {
-    throws IOException, ClassNotFoundException, InstantiationException,
-    IllegalAccessException, NoSuchMethodException, IllegalArgumentException,
-    InvocationTargetException
-  {
     copySmps(PLUGIN_A, PLUGIN_B);
 
     Set<InstalledPlugin> plugins = collectPlugins();
@@ -227,213 +229,88 @@ public class PluginProcessorTest
     // load parent class
     Class<?> clazz = cl.loadClass(PluginResource.class.getName());
 
-    assertSame(PluginResource.class, clazz);
+    assertThat(PluginResource.class).isSameAs(clazz);
 
     // load packaged class
     clazz = cl.loadClass("sonia.scm.plugins.HelloAgainService");
-    assertNotNull(clazz);
+    assertThat(clazz).isNotNull();
 
     Object instance = clazz.newInstance();
     Object result = clazz.getMethod("sayHelloAgain").invoke(instance);
 
-    assertEquals("hello again", result);
+    assertThat(result).isEqualTo("hello again");
   }
 
-  /**
-   * Method description
-   *
-   *
-   * @throws IOException
-   */
   @Test
-  public void testPluginWebResourceLoader() throws IOException
+  @SuppressWarnings("UnstableApiUsage")
-  {
+  void shouldCreatePluginWebResourceLoader() throws IOException {
     copySmp(PLUGIN_A);
 
     InstalledPlugin plugin = collectAndGetFirst();
     WebResourceLoader wrl = plugin.getWebResourceLoader();
-
+    assertThat(wrl).isNotNull();
-    assertNotNull(wrl);
 
     URL url = wrl.getResource("hello");
+    assertThat(url).isNotNull();
 
-    assertNotNull(url);
+    assertThat(Resources.toString(url, Charsets.UTF_8)).isEqualTo("hello");
-    assertThat(Resources.toString(url, Charsets.UTF_8), is("hello"));
   }
 
-  /**
-   * Method description
-   *
-   *
-   * @throws IOException
-   */
   @Test
-  public void testUpdate() throws IOException
+  void shouldDoPluginUpdate() throws IOException {
-  {
     copySmp(PLUGIN_F_1_0_0);
-
     InstalledPlugin plugin = collectAndGetFirst();
+    assertThat(plugin.getId()).isEqualTo(PLUGIN_F_1_0_0.id);
 
-    assertThat(plugin.getId(), is(PLUGIN_F_1_0_0.id));
     copySmp(PLUGIN_F_1_0_1);
     plugin = collectAndGetFirst();
-    assertThat(plugin.getId(), is(PLUGIN_F_1_0_1.id));
+    assertThat(plugin.getId()).isEqualTo(PLUGIN_F_1_0_1.id);
   }
 
-  //~--- set methods ----------------------------------------------------------
+  private InstalledPlugin collectAndGetFirst() throws IOException {
-
-  /**
-   * Method description
-   *
-   *
-   * @throws IOException
-   */
-  @Before
-  public void setUp() throws IOException
-  {
-    pluginDirectory = temp.newFolder();
-    processor = new PluginProcessor(ClassLoaderLifeCycle.create(), pluginDirectory.toPath());
-  }
-
-  //~--- methods --------------------------------------------------------------
-
-  /**
-   * Method description
-   *
-   *
-   * @return
-   *
-   * @throws IOException
-   */
-  private InstalledPlugin collectAndGetFirst() throws IOException
-  {
     Set<InstalledPlugin> plugins = collectPlugins();
 
-    assertThat(plugins, hasSize(1));
+    assertThat(plugins).hasSize(1);
 
     return Iterables.get(plugins, 0);
   }
 
-  /**
+  private Set<InstalledPlugin> collectPlugins() throws IOException {
-   * Method description
-   *
-   *
-   * @return
-   *
-   * @throws IOException
-   */
-  private Set<InstalledPlugin> collectPlugins() throws IOException
-  {
     return processor.collectPlugins(PluginProcessorTest.class.getClassLoader());
   }
 
-  /**
+  @SuppressWarnings("UnstableApiUsage")
-   * Method description
+  private void copySmp(PluginResource plugin) throws IOException {
-   *
-   *
-   * @param plugin
-   *
-   * @throws IOException
-   */
-  private void copySmp(PluginResource plugin) throws IOException
-  {
     URL resource = Resources.getResource(plugin.path);
     File file = new File(pluginDirectory, plugin.name);
 
-    try (OutputStream out = new FileOutputStream(file))
+    try (OutputStream out = new FileOutputStream(file)) {
-    {
       Resources.copy(resource, out);
     }
   }
 
-  /**
+  private void copySmps(PluginResource... plugins) throws IOException {
-   * Method description
+    for (PluginResource plugin : plugins) {
-   *
-   *
-   * @param plugins
-   *
-   * @throws IOException
-   */
-  private void copySmps(PluginResource... plugins) throws IOException
-  {
-    for (PluginResource plugin : plugins)
-    {
       copySmp(plugin);
     }
   }
 
-  /**
+  private InstalledPlugin findPlugin(Iterable<InstalledPlugin> plugin, final String id) {
-   * Method description
+    return Iterables.find(plugin, input -> id.equals(input.getId()));
-   *
-   *
-   * @param plugin
-   * @param id
-   *
-   * @return
-   */
-  private InstalledPlugin findPlugin(Iterable<InstalledPlugin> plugin,
-                                     final String id)
-  {
-    return Iterables.find(plugin, new Predicate<InstalledPlugin>()
-    {
-
-      @Override
-      public boolean apply(InstalledPlugin input)
-      {
-        return id.equals(input.getId());
-      }
-    });
   }
+  private static class PluginResource {
 
-  //~--- inner classes --------------------------------------------------------
+    private final String path;
+    private final String name;
+    private final String id;
 
-  /**
-   * Class description
-   *
-   *
-   * @version        Enter version here..., 14/12/06
-   * @author         Enter your name here...
-   */
-  private static class PluginResource
-  {
 
-    /**
+    public PluginResource(String path, String name, String id) {
-     * Constructs ...
-     *
-     *
-     * @param path
-     * @param name
-     * @param id
-     */
-    public PluginResource(String path, String name, String id)
-    {
       this.path = path;
       this.name = name;
       this.id = id;
     }
 
-    //~--- fields -------------------------------------------------------------
-
-    /** Field description */
-    private final String id;
-
-    /** Field description */
-    private final String name;
-
-    /** Field description */
-    private final String path;
   }
 
-
-  //~--- fields ---------------------------------------------------------------
-
-  /** Field description */
-  @Rule
-  public TemporaryFolder temp = new TemporaryFolder();
-
-  /** Field description */
-  private File pluginDirectory;
-
-  /** Field description */
-  private PluginProcessor processor;
 }

scm-webapp/src/test/java/sonia/scm/plugin/SmpDescriptorExtractorTest.java

@@ -63,11 +63,13 @@ class SmpDescriptorExtractorTest {
     "\n" +
     "</plugin>\n";
 
+  private final SmpDescriptorExtractor extractor = new SmpDescriptorExtractor();
+
   @Test
   void shouldExtractPluginXml(@TempDir Path tempDir) throws IOException {
     Path pluginFile = createZipFile(tempDir, "META-INF/scm/plugin.xml", PLUGIN_XML);
 
-    InstalledPluginDescriptor installedPluginDescriptor = new SmpDescriptorExtractor().extractPluginDescriptor(pluginFile);
+    InstalledPluginDescriptor installedPluginDescriptor = extractor.extractPluginDescriptor(pluginFile);
 
     Assertions.assertThat(installedPluginDescriptor.getInformation().getName()).isEqualTo("scm-test-plugin");
   }
@@ -76,14 +78,14 @@ class SmpDescriptorExtractorTest {
   void shouldFailWithoutPluginXml(@TempDir Path tempDir) throws IOException {
     Path pluginFile = createZipFile(tempDir, "META-INF/wrong/plugin.xml", PLUGIN_XML);
 
-    assertThrows(IOException.class, () -> new SmpDescriptorExtractor().extractPluginDescriptor(pluginFile));
+    assertThrows(IOException.class, () -> extractor.extractPluginDescriptor(pluginFile));
   }
 
   @Test
   void shouldFailWithIllegalPluginXml(@TempDir Path tempDir) throws IOException {
     Path pluginFile = createZipFile(tempDir, "META-INF/scm/plugin.xml", "<not><parsable>content</parsable></not>");
 
-    assertThrows(IOException.class, () -> new SmpDescriptorExtractor().extractPluginDescriptor(pluginFile));
+    assertThrows(IOException.class, () -> extractor.extractPluginDescriptor(pluginFile));
   }
 
   Path createZipFile(Path tempDir, String internalFileName, String content) throws IOException {

scm-webapp/src/test/resources/sonia/scm/plugin/scm-g-plugin.xml

@@ -0,0 +1,47 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!--
+
+    MIT License
+
+    Copyright (c) 2020-present Cloudogu GmbH and Contributors
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in all
+    copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+    SOFTWARE.
+
+-->
+<plugin>
+
+  <scm-version>2</scm-version>
+
+  <information>
+    <groupId>sonia.scm.plugins</groupId>
+    <artifactId>scm-g-plugin</artifactId>
+    <version>1.0.0</version>
+    <name>scm-g-plugin</name>
+    <description>Plugin g has a min version over 9000</description>
+  </information>
+
+  <conditions>
+    <min-version>9000.0.0</min-version>
+  </conditions>
+
+  <packages>
+    <package>sonia.scm.plugins</package>
+  </packages>
+
+</plugin>

scm-webapp/src/test/resources/sonia/scm/plugin/scm-h-plugin.xml

@@ -0,0 +1,43 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!--
+
+    MIT License
+
+    Copyright (c) 2020-present Cloudogu GmbH and Contributors
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in all
+    copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+    SOFTWARE.
+
+-->
+<plugin>
+
+  <scm-version>2</scm-version>
+
+  <information>
+    <groupId>sonia.scm.plugins</groupId>
+    <artifactId>scm-h-plugin</artifactId>
+    <version>1.0.0</version>
+    <name>scm-h-plugin</name>
+    <description>Plugin h is nothing special</description>
+  </information>
+
+  <packages>
+    <package>sonia.scm.plugins</package>
+  </packages>
+
+</plugin>

scm-webapp/src/test/resources/sonia/scm/plugin/scm-i-plugin.xml

@@ -0,0 +1,47 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!--
+
+    MIT License
+
+    Copyright (c) 2020-present Cloudogu GmbH and Contributors
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in all
+    copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+    SOFTWARE.
+
+-->
+<plugin>
+
+  <scm-version>2</scm-version>
+
+  <information>
+    <groupId>sonia.scm.plugins</groupId>
+    <artifactId>scm-i-plugin</artifactId>
+    <version>1.0.0</version>
+    <name>scm-i-plugin</name>
+    <description>Plugin i depends on h in version 1.2.0</description>
+  </information>
+
+  <packages>
+    <package>sonia.scm.plugins</package>
+  </packages>
+
+  <dependencies>
+    <dependency version="1.2.0">scm-h-plugin</dependency>
+  </dependencies>
+
+</plugin>

scm-webapp/src/test/resources/sonia/scm/plugin/scm-mail-plugin-2-0-0.xml

@@ -0,0 +1,43 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!--
+
+    MIT License
+
+    Copyright (c) 2020-present Cloudogu GmbH and Contributors
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in all
+    copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+    SOFTWARE.
+
+-->
+<plugin>
+
+  <scm-version>2</scm-version>
+
+  <information>
+    <groupId>sonia.scm.plugins</groupId>
+    <artifactId>scm-mail-plugin</artifactId>
+    <version>2.0.0</version>
+    <name>scm-mail-plugin</name>
+    <description>The awesome mail plugin</description>
+  </information>
+
+  <packages>
+    <package>sonia.scm.plugins</package>
+  </packages>
+
+</plugin>

scm-webapp/src/test/resources/sonia/scm/plugin/scm-mail-plugin-2-1-0.xml

@@ -0,0 +1,43 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!--
+
+    MIT License
+
+    Copyright (c) 2020-present Cloudogu GmbH and Contributors
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in all
+    copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+    SOFTWARE.
+
+-->
+<plugin>
+
+  <scm-version>2</scm-version>
+
+  <information>
+    <groupId>sonia.scm.plugins</groupId>
+    <artifactId>scm-mail-plugin</artifactId>
+    <version>2.1.0</version>
+    <name>scm-mail-plugin</name>
+    <description>The awesome mail plugin</description>
+  </information>
+
+  <packages>
+    <package>sonia.scm.plugins</package>
+  </packages>
+
+</plugin>

scm-webapp/src/test/resources/sonia/scm/plugin/scm-review-plugin-2-0-0.xml

@@ -0,0 +1,47 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!--
+
+    MIT License
+
+    Copyright (c) 2020-present Cloudogu GmbH and Contributors
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in all
+    copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+    SOFTWARE.
+
+-->
+<plugin>
+
+  <scm-version>2</scm-version>
+
+  <information>
+    <groupId>sonia.scm.plugins</groupId>
+    <artifactId>scm-review-plugin</artifactId>
+    <version>2.0.0</version>
+    <name>scm-review-plugin</name>
+    <description>The awesome review plugin</description>
+  </information>
+
+  <packages>
+    <package>sonia.scm.plugins</package>
+  </packages>
+
+  <dependencies>
+    <dependency version="2.0.0">scm-mail-plugin</dependency>
+  </dependencies>
+
+</plugin>

scm-webapp/src/test/resources/sonia/scm/plugin/scm-review-plugin-2-1-0.xml

@@ -0,0 +1,47 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!--
+
+    MIT License
+
+    Copyright (c) 2020-present Cloudogu GmbH and Contributors
+
+    Permission is hereby granted, free of charge, to any person obtaining a copy
+    of this software and associated documentation files (the "Software"), to deal
+    in the Software without restriction, including without limitation the rights
+    to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+    copies of the Software, and to permit persons to whom the Software is
+    furnished to do so, subject to the following conditions:
+
+    The above copyright notice and this permission notice shall be included in all
+    copies or substantial portions of the Software.
+
+    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+    IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+    FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+    AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+    LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+    OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+    SOFTWARE.
+
+-->
+<plugin>
+
+  <scm-version>2</scm-version>
+
+  <information>
+    <groupId>sonia.scm.plugins</groupId>
+    <artifactId>scm-review-plugin</artifactId>
+    <version>2.1.0</version>
+    <name>scm-review-plugin</name>
+    <description>The awesome review plugin</description>
+  </information>
+
+  <packages>
+    <package>sonia.scm.plugins</package>
+  </packages>
+
+  <dependencies>
+    <dependency version="2.1.0">scm-mail-plugin</dependency>
+  </dependencies>
+
+</plugin>