merge with develop

CHANGELOG.md

@@ -6,6 +6,10 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
 ## Unreleased
+### Added
+- Generation of email addresses for users, where none is configured ([#1370](https://github.com/scm-manager/scm-manager/pull/1370))
+
+## [2.7.1] - 2020-10-14
 ### Fixed
 - Null Pointer Exception on anonymous migration with deleted repositories ([#1371](https://github.com/scm-manager/scm-manager/pull/1371))
 - Null Pointer Exception on parsing SVN properties ([#1373](https://github.com/scm-manager/scm-manager/pull/1373))

docs/en/development/intellij-idea-configuration.md

@@ -11,6 +11,12 @@ title: Intellij IDEA Configuration
 
 ### Settings
 
+* Build, Execution, Deployment / Compiler
+    * Add runtime assertions for non-null-annotated methods and parameters (must be checked)
+    * Configure annotation ... (of "Add runtime assertions...")
+        * Nullable annotations: select (✓) `javax.annotation.Nullable`
+        * NotNull annotations: select (✓) `javax.annotation.Nonnull` and check Instrument
+
 * Run Configurations / Edit Configuration
     * Add Maven
     * Name: run-backend

pom.xml

@@ -903,7 +903,7 @@
 
   <properties>
     <!-- test libraries -->
-    <mockito.version>3.5.11</mockito.version>
+    <mockito.version>3.5.13</mockito.version>
     <hamcrest.version>2.1</hamcrest.version>
     <junit.version>5.7.0</junit.version>
 
@@ -913,7 +913,7 @@
     <servlet.version>3.1.0</servlet.version>
 
     <jaxrs.version>2.1.1</jaxrs.version>
-    <resteasy.version>4.5.7.Final</resteasy.version>
+    <resteasy.version>4.5.8.Final</resteasy.version>
     <jersey-client.version>1.19.4</jersey-client.version>
     <jackson.version>2.11.2</jackson.version>
     <guice.version>4.2.3</guice.version>

scm-core/src/main/java/sonia/scm/config/ScmConfiguration.java

@@ -80,6 +80,14 @@ public class ScmConfiguration implements Configuration {
    */
   public static final String DEFAULT_LOGIN_INFO_URL = "https://login-info.scm-manager.org/api/v1/login-info";
 
+  /**
+   * Default e-mail domain name that will be used whenever we have to generate an e-mail address for a user that has no
+   * mail address configured.
+   *
+   * @since 2.8.0
+   */
+  public static final String DEFAULT_MAIL_DOMAIN_NAME = "scm-manager.local";
+
   /**
    * Default plugin url from version 1.0
    */
@@ -195,6 +203,8 @@ public class ScmConfiguration implements Configuration {
   @XmlElement(name = "login-info-url")
   private String loginInfoUrl = DEFAULT_LOGIN_INFO_URL;
 
+  @XmlElement(name = "mail-domain-name")
+  private String mailDomainName = DEFAULT_MAIL_DOMAIN_NAME;
 
   /**
    * Calls the {@link sonia.scm.ConfigChangedListener#configChanged(Object)}
@@ -235,6 +245,7 @@ public class ScmConfiguration implements Configuration {
     this.namespaceStrategy = other.namespaceStrategy;
     this.loginInfoUrl = other.loginInfoUrl;
     this.releaseFeedUrl = other.releaseFeedUrl;
+    this.mailDomainName = other.mailDomainName;
     this.enabledUserConverter = other.enabledUserConverter;
   }
 
@@ -300,6 +311,15 @@ public class ScmConfiguration implements Configuration {
     return releaseFeedUrl;
   }
 
+  /**
+   * Returns the mail domain, that will be used to create e-mail addresses for users without one whenever one is required.
+   * @return default mail domain
+   * @since 2.8.0
+   */
+  public String getMailDomainName() {
+    return mailDomainName;
+  }
+
   /**
    * Returns a set of glob patterns for urls which should excluded from
    * proxy settings.
@@ -491,6 +511,16 @@ public class ScmConfiguration implements Configuration {
     this.releaseFeedUrl = releaseFeedUrl;
   }
 
+  /**
+   * Sets the mail host, that will be used to create e-mail addresses for users without one whenever one is required.
+   *
+   * @param mailDomainName The default mail domain to use
+   * @since 2.8.0
+   */
+  public void setMailDomainName(String mailDomainName) {
+    this.mailDomainName = mailDomainName;
+  }
+
   /**
    * Set glob patterns for urls which are should be excluded from proxy
    * settings.

scm-core/src/main/java/sonia/scm/repository/api/MergeCommandBuilder.java

@@ -30,7 +30,9 @@ import sonia.scm.repository.spi.MergeCommand;
 import sonia.scm.repository.spi.MergeCommandRequest;
 import sonia.scm.repository.spi.MergeConflictResult;
 import sonia.scm.repository.util.AuthorUtil;
+import sonia.scm.user.EMail;
 
+import javax.annotation.Nullable;
 import java.util.Set;
 
 /**
@@ -78,8 +80,12 @@ public class MergeCommandBuilder {
   private final MergeCommand mergeCommand;
   private final MergeCommandRequest request = new MergeCommandRequest();
 
-  MergeCommandBuilder(MergeCommand mergeCommand) {
+  @Nullable
+  private final EMail eMail;
+
+  MergeCommandBuilder(MergeCommand mergeCommand, @Nullable EMail eMail) {
     this.mergeCommand = mergeCommand;
+    this.eMail = eMail;
   }
 
   /**
@@ -209,7 +215,7 @@ public class MergeCommandBuilder {
    * @return The result of the merge.
    */
   public MergeCommandResult executeMerge() {
-    AuthorUtil.setAuthorIfNotAvailable(request);
+    AuthorUtil.setAuthorIfNotAvailable(request, eMail);
     Preconditions.checkArgument(request.isValid(), "revision to merge and target revision is required");
     return mergeCommand.merge(request);
   }

scm-core/src/main/java/sonia/scm/repository/api/ModifyCommandBuilder.java

@@ -35,8 +35,10 @@ import sonia.scm.repository.spi.ModifyCommand;
 import sonia.scm.repository.spi.ModifyCommandRequest;
 import sonia.scm.repository.util.AuthorUtil;
 import sonia.scm.repository.work.WorkdirProvider;
+import sonia.scm.user.EMail;
 import sonia.scm.util.IOUtil;
 
+import javax.annotation.Nullable;
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
@@ -51,7 +53,6 @@ import java.util.function.Consumer;
  *   default a {@link sonia.scm.AlreadyExistsException} will be thrown)</li>
  *   <li>modify existing files ({@link #modifyFile(String)}</li>
  *   <li>delete existing files ({@link #deleteFile(String)}</li>
- *   <li>move/rename existing files ({@link #moveFile(String, String)}</li>
  * </ul>
  *
  * You can collect multiple changes before they are executed with a call to {@link #execute()}.
@@ -75,11 +76,15 @@ public class ModifyCommandBuilder {
   private final ModifyCommand command;
   private final File workdir;
 
+  @Nullable
+  private final EMail eMail;
+
   private final ModifyCommandRequest request = new ModifyCommandRequest();
 
-  ModifyCommandBuilder(ModifyCommand command, WorkdirProvider workdirProvider) {
+  ModifyCommandBuilder(ModifyCommand command, WorkdirProvider workdirProvider, @Nullable EMail eMail) {
     this.command = command;
     this.workdir = workdirProvider.createNewWorkdir();
+    this.eMail = eMail;
   }
 
   /**
@@ -124,7 +129,7 @@ public class ModifyCommandBuilder {
    * @return The revision of the new commit.
    */
   public String execute() {
-    AuthorUtil.setAuthorIfNotAvailable(request);
+    AuthorUtil.setAuthorIfNotAvailable(request, eMail);
     try {
       Preconditions.checkArgument(request.isValid(), "commit message and at least one request are required");
       return command.execute(request);

scm-core/src/main/java/sonia/scm/repository/api/RepositoryService.java

@@ -34,7 +34,9 @@ import sonia.scm.repository.Repository;
 import sonia.scm.repository.RepositoryPermissions;
 import sonia.scm.repository.spi.RepositoryServiceProvider;
 import sonia.scm.repository.work.WorkdirProvider;
+import sonia.scm.user.EMail;
 
+import javax.annotation.Nullable;
 import java.io.Closeable;
 import java.io.IOException;
 import java.util.Set;
@@ -84,30 +86,36 @@ public final class RepositoryService implements Closeable {
   private final PreProcessorUtil preProcessorUtil;
   private final RepositoryServiceProvider provider;
   private final Repository repository;
-  @SuppressWarnings("rawtypes")
+  @SuppressWarnings({"rawtypes", "java:S3740"})
   private final Set<ScmProtocolProvider> protocolProviders;
   private final WorkdirProvider workdirProvider;
 
+  @Nullable
+  private final EMail eMail;
+
   /**
    * Constructs a new {@link RepositoryService}. This constructor should only
    * be called from the {@link RepositoryServiceFactory}.
    * @param cacheManager     cache manager
    * @param provider         implementation for {@link RepositoryServiceProvider}
    * @param repository       the repository
-   * @param workdirProvider
+   * @param workdirProvider  provider for workdirs
+   * @param eMail            utility to compute email addresses if missing
    */
   RepositoryService(CacheManager cacheManager,
-                    RepositoryServiceProvider provider, Repository repository,
+                    RepositoryServiceProvider provider,
+                    Repository repository,
                     PreProcessorUtil preProcessorUtil,
-                    @SuppressWarnings("rawtypes") Set<ScmProtocolProvider> protocolProviders,
+                    @SuppressWarnings({"rawtypes", "java:S3740"}) Set<ScmProtocolProvider> protocolProviders,
-                    WorkdirProvider workdirProvider
+                    WorkdirProvider workdirProvider,
-  ) {
+                    @Nullable EMail eMail) {
     this.cacheManager = cacheManager;
     this.provider = provider;
     this.repository = repository;
     this.preProcessorUtil = preProcessorUtil;
     this.protocolProviders = protocolProviders;
     this.workdirProvider = workdirProvider;
+    this.eMail = eMail;
   }
 
   /**
@@ -397,7 +405,7 @@ public final class RepositoryService implements Closeable {
     LOG.debug("create merge command for repository {}",
       repository.getNamespaceAndName());
 
-    return new MergeCommandBuilder(provider.getMergeCommand());
+    return new MergeCommandBuilder(provider.getMergeCommand(), eMail);
   }
 
   /**
@@ -418,7 +426,7 @@ public final class RepositoryService implements Closeable {
     LOG.debug("create modify command for repository {}",
       repository.getNamespaceAndName());
 
-    return new ModifyCommandBuilder(provider.getModifyCommand(), workdirProvider);
+    return new ModifyCommandBuilder(provider.getModifyCommand(), workdirProvider, eMail);
   }
 
   /**
@@ -448,7 +456,7 @@ public final class RepositoryService implements Closeable {
       .map(this::createProviderInstanceForRepository);
   }
 
-  @SuppressWarnings("rawtypes")
+  @SuppressWarnings({"rawtypes", "java:S3740"})
   private ScmProtocol createProviderInstanceForRepository(ScmProtocolProvider protocolProvider) {
     return protocolProvider.get(repository);
   }

scm-core/src/main/java/sonia/scm/repository/api/RepositoryServiceFactory.java

@@ -42,7 +42,6 @@ import sonia.scm.cache.Cache;
 import sonia.scm.cache.CacheManager;
 import sonia.scm.config.ScmConfiguration;
 import sonia.scm.event.ScmEventBus;
-import sonia.scm.repository.BranchCreatedEvent;
 import sonia.scm.repository.ClearRepositoryCacheEvent;
 import sonia.scm.repository.NamespaceAndName;
 import sonia.scm.repository.PostReceiveRepositoryHookEvent;
@@ -58,7 +57,9 @@ import sonia.scm.repository.work.WorkdirProvider;
 import sonia.scm.security.PublicKeyCreatedEvent;
 import sonia.scm.security.PublicKeyDeletedEvent;
 import sonia.scm.security.ScmSecurityException;
+import sonia.scm.user.EMail;
 
+import javax.annotation.Nullable;
 import java.util.Set;
 
 import static sonia.scm.ContextEntry.ContextBuilder.entity;
@@ -115,7 +116,17 @@ public final class RepositoryServiceFactory {
   private static final Logger logger =
     LoggerFactory.getLogger(RepositoryServiceFactory.class);
 
-  //~--- constructors ---------------------------------------------------------
+  private final CacheManager cacheManager;
+  private final RepositoryManager repositoryManager;
+  private final Set<RepositoryServiceResolver> resolvers;
+  private final PreProcessorUtil preProcessorUtil;
+  @SuppressWarnings({"rawtypes", "java:S3740"})
+  private final Set<ScmProtocolProvider> protocolProviders;
+  private final WorkdirProvider workdirProvider;
+
+  @Nullable
+  private final EMail eMail;
+
 
   /**
    * Constructs a new {@link RepositoryServiceFactory}. This constructor
@@ -127,40 +138,67 @@ public final class RepositoryServiceFactory {
    * @param repositoryManager manager for repositories
    * @param resolvers         a set of {@link RepositoryServiceResolver}
    * @param preProcessorUtil  helper object for pre processor handling
-   * @param protocolProviders
+   * @param protocolProviders providers for repository protocols
-   * @param workdirProvider
+   * @param workdirProvider   provider for working directories
+   *
+   * @deprecated use {@link RepositoryServiceFactory#RepositoryServiceFactory(CacheManager, RepositoryManager, Set, PreProcessorUtil, Set, WorkdirProvider, EMail)} instead
    * @since 1.21
    */
-  @Inject
+  @Deprecated
   public RepositoryServiceFactory(ScmConfiguration configuration,
                                   CacheManager cacheManager, RepositoryManager repositoryManager,
                                   Set<RepositoryServiceResolver> resolvers, PreProcessorUtil preProcessorUtil,
-                                  @SuppressWarnings("rawtypes") Set<ScmProtocolProvider> protocolProviders, WorkdirProvider workdirProvider) {
+                                  @SuppressWarnings({"rawtypes", "java:S3740"}) Set<ScmProtocolProvider> protocolProviders,
+                                  WorkdirProvider workdirProvider) {
     this(
-      configuration, cacheManager, repositoryManager, resolvers,
+      cacheManager, repositoryManager, resolvers,
-      preProcessorUtil, protocolProviders, workdirProvider, ScmEventBus.getInstance()
+      preProcessorUtil, protocolProviders, workdirProvider, null, ScmEventBus.getInstance()
+    );
+  }
+
+  /**
+   * Constructs a new {@link RepositoryServiceFactory}. This constructor
+   * should not be called manually, it should only be used by the injection
+   * container.
+   *
+   * @param cacheManager      cache manager
+   * @param repositoryManager manager for repositories
+   * @param resolvers         a set of {@link RepositoryServiceResolver}
+   * @param preProcessorUtil  helper object for pre processor handling
+   * @param protocolProviders providers for repository protocols
+   * @param workdirProvider   provider for working directories
+   * @param eMail             handling user emails
+   * @since 2.8.0
+   */
+  @Inject
+  public RepositoryServiceFactory(CacheManager cacheManager, RepositoryManager repositoryManager,
+                                  Set<RepositoryServiceResolver> resolvers, PreProcessorUtil preProcessorUtil,
+                                  @SuppressWarnings({"rawtypes", "java:S3740"})  Set<ScmProtocolProvider> protocolProviders,
+                                  WorkdirProvider workdirProvider, EMail eMail) {
+    this(
+      cacheManager, repositoryManager, resolvers,
+      preProcessorUtil, protocolProviders, workdirProvider,
+      eMail, ScmEventBus.getInstance()
     );
   }
 
   @VisibleForTesting
-  RepositoryServiceFactory(ScmConfiguration configuration,
+  @SuppressWarnings("java:S107") // to keep backward compatibility, we can not reduce amount of parameters
-                           CacheManager cacheManager, RepositoryManager repositoryManager,
+  RepositoryServiceFactory(CacheManager cacheManager, RepositoryManager repositoryManager,
                            Set<RepositoryServiceResolver> resolvers, PreProcessorUtil preProcessorUtil,
-                           Set<ScmProtocolProvider> protocolProviders, WorkdirProvider workdirProvider,
+                           @SuppressWarnings({"rawtypes", "java:S3740"}) Set<ScmProtocolProvider> protocolProviders,
-                           ScmEventBus eventBus) {
+                           WorkdirProvider workdirProvider, @Nullable EMail eMail, ScmEventBus eventBus) {
-    this.configuration = configuration;
     this.cacheManager = cacheManager;
     this.repositoryManager = repositoryManager;
     this.resolvers = resolvers;
     this.preProcessorUtil = preProcessorUtil;
     this.protocolProviders = protocolProviders;
     this.workdirProvider = workdirProvider;
+    this.eMail = eMail;
 
     eventBus.register(new CacheClearHook(cacheManager));
   }
 
-  //~--- methods --------------------------------------------------------------
-
   /**
    * Creates a new RepositoryService for the given repository.
    *
@@ -246,7 +284,7 @@ public final class RepositoryServiceFactory {
         }
 
         service = new RepositoryService(cacheManager, provider, repository,
-          preProcessorUtil, protocolProviders, workdirProvider);
+          preProcessorUtil, protocolProviders, workdirProvider, eMail);
 
         break;
       }
@@ -259,8 +297,6 @@ public final class RepositoryServiceFactory {
     return service;
   }
 
-  //~--- inner classes --------------------------------------------------------
-
   /**
    * Hook and listener to clear all relevant repository caches.
    */
@@ -284,8 +320,6 @@ public final class RepositoryServiceFactory {
       this.caches.add(cacheManager.getCache(BranchesCommandBuilder.CACHE_NAME));
     }
 
-    //~--- methods ------------------------------------------------------------
-
     /**
      * Clear caches on explicit repository cache clear event.
      *
@@ -347,35 +381,4 @@ public final class RepositoryServiceFactory {
     }
   }
 
-
-  //~--- fields ---------------------------------------------------------------
-
-  /**
-   * cache manager
-   */
-  private final CacheManager cacheManager;
-
-  /**
-   * scm-manager configuration
-   */
-  private final ScmConfiguration configuration;
-
-  /**
-   * pre processor util
-   */
-  private final PreProcessorUtil preProcessorUtil;
-
-  /**
-   * repository manager
-   */
-  private final RepositoryManager repositoryManager;
-
-  /**
-   * service resolvers
-   */
-  private final Set<RepositoryServiceResolver> resolvers;
-
-  private Set<ScmProtocolProvider> protocolProviders;
-
-  private final WorkdirProvider workdirProvider;
 }

scm-core/src/main/java/sonia/scm/repository/util/AuthorUtil.java

@@ -27,22 +27,29 @@ package sonia.scm.repository.util;
 import org.apache.shiro.SecurityUtils;
 import org.apache.shiro.subject.Subject;
 import sonia.scm.repository.Person;
+import sonia.scm.user.EMail;
 import sonia.scm.user.User;
 
+import javax.annotation.Nullable;
+
 public class AuthorUtil {
 
   public static void setAuthorIfNotAvailable(CommandWithAuthor request) {
+    setAuthorIfNotAvailable(request, null);
+  }
+
+  public static void setAuthorIfNotAvailable(CommandWithAuthor request, @Nullable EMail eMail) {
     if (request.getAuthor() == null) {
-      request.setAuthor(createAuthorFromSubject());
+      request.setAuthor(createAuthorFromSubject(eMail));
     }
   }
 
-  private static Person createAuthorFromSubject() {
+  private static Person createAuthorFromSubject(@Nullable EMail eMail) {
     Subject subject = SecurityUtils.getSubject();
     User user = subject.getPrincipals().oneByType(User.class);
     String name = user.getDisplayName();
-    String email = user.getMail();
+    String mailAddress = eMail != null ? eMail.getMailOrFallback(user) : user.getMail();
-    return new Person(name, email);
+    return new Person(name, mailAddress);
   }
 
   public interface CommandWithAuthor {

scm-core/src/main/java/sonia/scm/user/EMail.java

@@ -0,0 +1,71 @@
+/*
+ * 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.user;
+
+import com.google.common.base.Strings;
+import sonia.scm.config.ScmConfiguration;
+import sonia.scm.util.ValidationUtil;
+
+import javax.inject.Inject;
+
+/**
+ * Email is able to resolve email addresses of users.
+ *
+ * @since 2.8.0
+ */
+public class EMail {
+
+  private final ScmConfiguration scmConfiguration;
+
+  @Inject
+  public EMail(ScmConfiguration scmConfiguration) {
+    this.scmConfiguration = scmConfiguration;
+  }
+
+  /**
+   * Returns the email address of the given user or a generated fallback address.
+   * @param user user to resolve address from
+   * @return email address or fallback
+   */
+  public String getMailOrFallback(User user) {
+    if (Strings.isNullOrEmpty(user.getMail())) {
+      if (isMailUsedAsId(user)) {
+        return user.getId();
+      } else {
+        return createFallbackMail(user);
+      }
+    } else {
+      return user.getMail();
+    }
+  }
+
+  private boolean isMailUsedAsId(User user) {
+    return ValidationUtil.isMailAddressValid(user.getId());
+  }
+
+  private String createFallbackMail(User user) {
+    return user.getId() + "@" + scmConfiguration.getMailDomainName();
+  }
+}

scm-core/src/test/java/sonia/scm/repository/api/ModifyCommandBuilderTest.java

@@ -25,7 +25,12 @@
 package sonia.scm.repository.api;
 
 import com.google.common.io.ByteSource;
+import org.apache.shiro.subject.PrincipalCollection;
+import org.apache.shiro.subject.Subject;
+import org.apache.shiro.util.ThreadContext;
+import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Nested;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.junit.jupiter.api.io.TempDir;
@@ -34,10 +39,12 @@ import org.mockito.Mock;
 import org.mockito.invocation.InvocationOnMock;
 import org.mockito.junit.jupiter.MockitoExtension;
 import org.mockito.stubbing.Answer;
-import sonia.scm.repository.Person;
+import sonia.scm.config.ScmConfiguration;
 import sonia.scm.repository.spi.ModifyCommand;
 import sonia.scm.repository.spi.ModifyCommandRequest;
 import sonia.scm.repository.work.WorkdirProvider;
+import sonia.scm.user.EMail;
+import sonia.scm.user.User;
 
 import java.io.ByteArrayInputStream;
 import java.io.File;
@@ -50,15 +57,19 @@ import java.util.List;
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.anyBoolean;
+import static org.mockito.ArgumentMatchers.argThat;
 import static org.mockito.Mockito.doAnswer;
 import static org.mockito.Mockito.doNothing;
 import static org.mockito.Mockito.lenient;
+import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.verify;
 import static org.mockito.Mockito.when;
 
 @ExtendWith(MockitoExtension.class)
 class ModifyCommandBuilderTest {
 
+  private static final ScmConfiguration SCM_CONFIGURATION = new ScmConfiguration();
+
   @Mock
   ModifyCommand command;
   @Mock
@@ -73,7 +84,7 @@ class ModifyCommandBuilderTest {
   void initWorkdir(@TempDir Path temp) throws IOException {
     workdir = Files.createDirectory(temp.resolve("workdir"));
     lenient().when(workdirProvider.createNewWorkdir()).thenReturn(workdir.toFile());
-    commandBuilder = new ModifyCommandBuilder(command, workdirProvider);
+    commandBuilder = new ModifyCommandBuilder(command, workdirProvider, new EMail(SCM_CONFIGURATION));
   }
 
   @BeforeEach
@@ -89,6 +100,48 @@ class ModifyCommandBuilderTest {
     );
   }
 
+  private ModifyCommandBuilder initCommand() {
+    return commandBuilder
+      .setBranch("branch")
+      .setCommitMessage("message");
+  }
+
+  private void mockLoggedInUser(User loggedInUser) {
+    Subject subject = mock(Subject.class);
+    ThreadContext.bind(subject);
+    PrincipalCollection principals = mock(PrincipalCollection.class);
+    when(subject.getPrincipals()).thenReturn(principals);
+    when(principals.oneByType(User.class)).thenReturn(loggedInUser);
+  }
+
+  @AfterEach
+  void unbindSubjec() {
+    ThreadContext.unbindSubject();
+  }
+
+  private static class ExtractContent implements Answer {
+
+    private final List<String> contentCaptor;
+
+    public ExtractContent(List<String> contentCaptor) {
+      this.contentCaptor = contentCaptor;
+    }
+
+    @Override
+    public Object answer(InvocationOnMock invocation) throws Throwable {
+      return contentCaptor.add(Files.readAllLines(((File) invocation.getArgument(1)).toPath()).get(0));
+    }
+  }
+
+  @Nested
+  class WithUserWithMail {
+
+    @BeforeEach
+    void initSubject() {
+      User loggedInUser = new User("dent", "Arthur", "dent@hitchhiker.com");
+      mockLoggedInUser(loggedInUser);
+    }
+
     @Test
     void shouldReturnTargetRevisionFromCommit() {
       String targetRevision = initCommand()
@@ -198,13 +251,6 @@ class ModifyCommandBuilderTest {
       assertThat(contentCaptor).contains("content");
     }
 
-  private ModifyCommandBuilder initCommand() {
-    return commandBuilder
-      .setBranch("branch")
-      .setCommitMessage("message")
-      .setAuthor(new Person());
-  }
-
     @Test
     void shouldDeleteTemporaryFiles(@TempDir Path temp) throws IOException {
       ArgumentCaptor<String> nameCaptor = ArgumentCaptor.forClass(String.class);
@@ -218,16 +264,39 @@ class ModifyCommandBuilderTest {
       assertThat(Files.list(temp)).isEmpty();
     }
 
-  private static class ExtractContent implements Answer {
+    @Test
-    private final List<String> contentCaptor;
+    void shouldUseMailFromUser() throws IOException {
+      initCommand()
+        .modifyFile("toBeModified").withData(ByteSource.wrap("content".getBytes()))
+        .execute();
 
-    public ExtractContent(List<String> contentCaptor) {
+      verify(command).execute(argThat(modifyCommandRequest -> {
-      this.contentCaptor = contentCaptor;
+        assertThat(modifyCommandRequest.getAuthor().getMail()).isEqualTo("dent@hitchhiker.com");
+        return true;
+      }));
+    }
   }
 
-    @Override
+  @Nested
-    public Object answer(InvocationOnMock invocation) throws Throwable {
+  class WithUserWithoutMail {
-      return contentCaptor.add(Files.readAllLines(((File) invocation.getArgument(1)).toPath()).get(0));
+
+    @BeforeEach
+    void initSubject() {
+      User loggedInUser = new User("dent", "Arthur", null);
+      mockLoggedInUser(loggedInUser);
+    }
+
+    @Test
+    void shouldUseMailFromUser() throws IOException {
+      SCM_CONFIGURATION.setMailDomainName("heart-of-gold.local");
+      initCommand()
+        .modifyFile("toBeModified").withData(ByteSource.wrap("content".getBytes()))
+        .execute();
+
+      verify(command).execute(argThat(modifyCommandRequest -> {
+        assertThat(modifyCommandRequest.getAuthor().getMail()).isEqualTo("dent@heart-of-gold.local");
+        return true;
+      }));
     }
   }
 }

scm-core/src/test/java/sonia/scm/repository/api/RepositoryServiceFactoryTest.java

@@ -46,6 +46,7 @@ import sonia.scm.repository.RepositoryManager;
 import sonia.scm.repository.spi.RepositoryServiceProvider;
 import sonia.scm.repository.spi.RepositoryServiceResolver;
 import sonia.scm.repository.work.WorkdirProvider;
+import sonia.scm.user.EMail;
 
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.jupiter.api.Assertions.assertThrows;
@@ -56,9 +57,6 @@ import static org.mockito.Mockito.when;
 @ExtendWith(MockitoExtension.class)
 class RepositoryServiceFactoryTest {
 
-  @Mock
-  private ScmConfiguration configuration;
-
   @Mock(answer = Answers.RETURNS_MOCKS)
   private CacheManager cacheManager;
 
@@ -94,8 +92,9 @@ class RepositoryServiceFactoryTest {
       builder.add(repositoryServiceResolver);
     }
     return new RepositoryServiceFactory(
-      configuration, cacheManager, repositoryManager, builder.build(),
+      cacheManager, repositoryManager, builder.build(),
-      preProcessorUtil, ImmutableSet.of(), workdirProvider, eventBus
+      preProcessorUtil, ImmutableSet.of(), workdirProvider,
+      new EMail(new ScmConfiguration()), eventBus
     );
   }
 

scm-core/src/test/java/sonia/scm/repository/api/RepositoryServiceTest.java

@@ -25,9 +25,11 @@
 package sonia.scm.repository.api;
 
 import org.junit.Test;
+import sonia.scm.config.ScmConfiguration;
 import sonia.scm.repository.Repository;
 import sonia.scm.repository.spi.HttpScmProtocol;
 import sonia.scm.repository.spi.RepositoryServiceProvider;
+import sonia.scm.user.EMail;
 
 import javax.servlet.ServletConfig;
 import javax.servlet.http.HttpServletRequest;
@@ -46,9 +48,11 @@ public class RepositoryServiceTest {
   private final RepositoryServiceProvider provider = mock(RepositoryServiceProvider.class);
   private final Repository repository = new Repository("", "git", "space", "repo");
 
+  private final EMail eMail = new EMail(new ScmConfiguration());
+
   @Test
   public void shouldReturnMatchingProtocolsFromProvider() {
-    RepositoryService repositoryService = new RepositoryService(null, provider, repository, null, Collections.singleton(new DummyScmProtocolProvider()), null);
+    RepositoryService repositoryService = new RepositoryService(null, provider, repository, null, Collections.singleton(new DummyScmProtocolProvider()), null, eMail);
     Stream<ScmProtocol> supportedProtocols = repositoryService.getSupportedProtocols();
 
     assertThat(sizeOf(supportedProtocols.collect(Collectors.toList()))).isEqualTo(1);
@@ -56,7 +60,7 @@ public class RepositoryServiceTest {
 
   @Test
   public void shouldFindKnownProtocol() {
-    RepositoryService repositoryService = new RepositoryService(null, provider, repository, null, Collections.singleton(new DummyScmProtocolProvider()), null);
+    RepositoryService repositoryService = new RepositoryService(null, provider, repository, null, Collections.singleton(new DummyScmProtocolProvider()), null, eMail);
 
     HttpScmProtocol protocol = repositoryService.getProtocol(HttpScmProtocol.class);
 
@@ -65,11 +69,9 @@ public class RepositoryServiceTest {
 
   @Test
   public void shouldFailForUnknownProtocol() {
-    RepositoryService repositoryService = new RepositoryService(null, provider, repository, null, Collections.singleton(new DummyScmProtocolProvider()), null);
+    RepositoryService repositoryService = new RepositoryService(null, provider, repository, null, Collections.singleton(new DummyScmProtocolProvider()), null, eMail);
 
-    assertThrows(IllegalArgumentException.class, () -> {
+    assertThrows(IllegalArgumentException.class, () -> repositoryService.getProtocol(UnknownScmProtocol.class));
-      repositoryService.getProtocol(UnknownScmProtocol.class);
-    });
   }
 
   private static class DummyHttpProtocol extends HttpScmProtocol {

scm-core/src/test/java/sonia/scm/repository/util/AuthorUtilTest.java

@@ -0,0 +1,114 @@
+/*
+ * 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.repository.util;
+
+import org.apache.shiro.subject.Subject;
+import org.apache.shiro.util.ThreadContext;
+import org.junit.jupiter.api.AfterEach;
+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 sonia.scm.repository.Person;
+import sonia.scm.user.EMail;
+import sonia.scm.user.User;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.when;
+
+@ExtendWith(MockitoExtension.class)
+class AuthorUtilTest {
+
+  @Mock
+  private EMail eMail;
+
+  @Mock(answer = Answers.RETURNS_DEEP_STUBS)
+  private Subject subject;
+
+  @BeforeEach
+  void setUpSubject() {
+    ThreadContext.bind(subject);
+  }
+
+  @AfterEach
+  void tearDownSubject() {
+    ThreadContext.unbindSubject();
+  }
+
+  @Test
+  void shouldCreateMailAddressFromEmail() {
+    User trillian = new User("trillian");
+    when(subject.getPrincipals().oneByType(User.class)).thenReturn(trillian);
+    when(eMail.getMailOrFallback(trillian)).thenReturn("tricia@hitchhicker.com");
+
+    Command command = new Command(null);
+    AuthorUtil.setAuthorIfNotAvailable(command, eMail);
+
+    assertThat(command.getAuthor().getMail()).isEqualTo("tricia@hitchhicker.com");
+  }
+
+  @Test
+  void shouldUseUsersMailAddressWithoutEMail() {
+    User trillian = new User("trillian", "Trillian", "trillian.mcmillan@hitchhiker.com");
+    when(subject.getPrincipals().oneByType(User.class)).thenReturn(trillian);
+
+    Command command = new Command(null);
+    AuthorUtil.setAuthorIfNotAvailable(command);
+
+    assertThat(command.getAuthor().getMail()).isEqualTo("trillian.mcmillan@hitchhiker.com");
+  }
+
+  @Test
+  void shouldKeepExistingAuthor() {
+    Person person = new Person("Trillian McMillan", "trillian.mcmillian@hitchhiker.com");
+
+    Command command = new Command(person);
+    AuthorUtil.setAuthorIfNotAvailable(command);
+
+    assertThat(command.getAuthor()).isSameAs(person);
+  }
+
+  public static class Command implements AuthorUtil.CommandWithAuthor {
+
+    private Person person;
+
+    public Command(Person person) {
+      this.person = person;
+    }
+
+    @Override
+    public Person getAuthor() {
+      return person;
+    }
+
+    @Override
+    public void setAuthor(Person person) {
+      this.person = person;
+    }
+  }
+
+}

scm-core/src/test/java/sonia/scm/user/EMailTest.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.user;
+
+import org.junit.jupiter.api.Test;
+import sonia.scm.config.ScmConfiguration;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class EMailTest {
+
+  EMail eMail = new EMail(new ScmConfiguration());
+
+  @Test
+  void shouldUserUsersAddressIfAvailable() {
+    User user = new User("dent", "Arthur Dent", "arthur@hitchhiker.com");
+
+    String mailAddress = eMail.getMailOrFallback(user);
+
+    assertThat(mailAddress).isEqualTo("arthur@hitchhiker.com");
+  }
+
+  @Test
+  void shouldCreateAddressIfNoneAvailable() {
+    User user = new User("dent", "Arthur Dent", "");
+
+    String mailAddress = eMail.getMailOrFallback(user);
+
+    assertThat(mailAddress).isEqualTo("dent@scm-manager.local");
+  }
+
+  @Test
+  void shouldUserUsersIdIfItLooksLikeAnMailAddress() {
+    User user = new User("dent@hitchhiker.com", "Arthur Dent", "");
+
+    String mailAddress = eMail.getMailOrFallback(user);
+
+    assertThat(mailAddress).isEqualTo("dent@hitchhiker.com");
+  }
+}

scm-ui/ui-components/src/repos/CommitAuthor.tsx

@@ -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.
+ */
+
+import React, { FC } from "react";
+import { useTranslation } from "react-i18next";
+import Notification from "../Notification";
+import { Me } from "@scm-manager/ui-types";
+import { connect } from "react-redux";
+
+type Props = {
+  // props from global state
+  me: Me;
+};
+
+const CommitAuthor: FC<Props> = ({ me }) => {
+  const [t] = useTranslation("repos");
+
+  const mail = me.mail ? me.mail : me.fallbackMail;
+
+  return (
+    <>
+      {!me.mail && <Notification type="warning">{t("commit.commitAuthor.noMail")}</Notification>}
+      <span className="mb-2">
+        <strong>{t("commit.commitAuthor.author")}</strong> {`${me.displayName} <${mail}>`}
+      </span>
+    </>
+  );
+};
+
+const mapStateToProps = (state: any) => {
+  const { auth } = state;
+  const me = auth.me;
+
+  return {
+    me
+  };
+};
+
+export default connect(mapStateToProps)(CommitAuthor);

scm-ui/ui-components/src/repos/index.ts

@@ -52,6 +52,7 @@ export { default as RepositoryAvatar } from "./RepositoryAvatar";
 export { default as RepositoryEntry } from "./RepositoryEntry";
 export { default as RepositoryEntryLink } from "./RepositoryEntryLink";
 export { default as JumpToFileButton } from "./JumpToFileButton";
+export { default as CommitAuthor } from "./CommitAuthor";
 
 export {
   File,

scm-ui/ui-types/src/Config.ts

@@ -49,5 +49,6 @@ export type Config = {
   namespaceStrategy: string;
   loginInfoUrl: string;
   releaseFeedUrl: string;
+  mailDomainName: string;
   _links: Links;
 };

scm-ui/ui-types/src/Me.ts

@@ -27,7 +27,8 @@ import { Links } from "./hal";
 export type Me = {
   name: string;
   displayName: string;
-  mail: string;
+  mail?: string;
+  fallbackMail?: string;
   groups: string[];
   _links: Links;
 };

scm-ui/ui-types/src/User.ts

@@ -27,13 +27,13 @@ import { Links } from "./hal";
 export type DisplayedUser = {
   id: string;
   displayName: string;
-  mail: string;
+  mail?: string;
 };
 
 export type User = {
   displayName: string;
   name: string;
-  mail: string;
+  mail?: string;
   password: string;
   active: boolean;
   type?: string;

scm-ui/ui-webapp/public/locales/de/config.json

@@ -47,6 +47,7 @@
     "skip-failed-authenticators": "Fehlgeschlagene Authentifizierer überspringen",
     "plugin-url": "Plugin Center URL",
     "release-feed-url": "Release Feed URL",
+    "mail-domain-name": "Fallback E-Mail Domain Name",
     "enabled-xsrf-protection": "XSRF Protection aktivieren",
     "enabled-user-converter": "Benutzer Konverter aktivieren",
     "namespace-strategy": "Namespace Strategie",
@@ -63,6 +64,7 @@
     "dateFormatHelpText": "Moments Datumsformat. Zulässige Formate sind in der MomentJS Dokumentation beschrieben.",
     "pluginUrlHelpText": "Die URL der Plugin Center API. Beschreibung der Platzhalter: version = SCM-Manager Version; os = Betriebssystem; arch = Architektur",
     "releaseFeedUrlHelpText": "Die URL des RSS Release Feed des SCM-Manager. Darüber wird über die neue SCM-Manager Version informiert. Um diese Funktion zu deaktivieren lassen Sie dieses Feld leer.",
+    "mailDomainNameHelpText": "Dieser Domain Name wird genutzt, wenn für einen User eine E-Mail-Adresse benötigt wird, für den keine hinterlegt ist. Diese Domain wird nicht zum Versenden von E-Mails genutzt und auch keine anderweitige Verbindung aufgebaut.",
     "enableForwardingHelpText": "mod_proxy Port Weiterleitung aktivieren.",
     "disableGroupingGridHelpText": "Repository Gruppen deaktivieren. Nach einer Änderung an dieser Einstellung muss die Seite komplett neu geladen werden.",
     "allowAnonymousAccessHelpText": "Anonyme Benutzer haben Zugriff auf freigegebene Repositories.",

scm-ui/ui-webapp/public/locales/de/repos.json

@@ -135,6 +135,12 @@
       "sources": "Sources"
     }
   },
+  "commit": {
+    "commitAuthor": {
+      "author": "Autor",
+      "noMail": "Für den aktuellen Benutzer existiert keine E-Mail-Adresse. Es wird die unten angezeigte generierte Adresse genutzt."
+    }
+  },
   "repositoryForm": {
     "subtitle": "Repository bearbeiten",
     "submit": "Speichern",
@@ -269,4 +275,4 @@
     "clickHere": "Klicken Sie hier um Ihre Datei hochzuladen.",
     "dragAndDrop": "Sie können Ihre Datei auch direkt in die Dropzone ziehen."
   }
-}
+},

scm-ui/ui-webapp/public/locales/en/config.json

@@ -47,6 +47,7 @@
     "skip-failed-authenticators": "Skip Failed Authenticators",
     "plugin-url": "Plugin Center URL",
     "release-feed-url": "Release Feed URL",
+    "mail-domain-name": "Fallback Mail Domain Name",
     "enabled-xsrf-protection": "Enabled XSRF Protection",
     "enabled-user-converter": "Enabled User Converter",
     "namespace-strategy": "Namespace Strategy",
@@ -63,6 +64,7 @@
     "dateFormatHelpText": "Moments date format. Please have a look at the MomentJS documentation.",
     "pluginUrlHelpText": "The url of the Plugin Center API. Explanation of the placeholders: version = SCM-Manager Version; os = Operation System; arch = Architecture",
     "releaseFeedUrlHelpText": "The url of the RSS Release Feed for SCM-Manager. This provides up-to-date version information. To disable this feature just leave the url blank.",
+    "mailDomainNameHelpText": "This domain name will be used to create email addresses for users without one when needed. It will not be used to send mails nor will be accessed otherwise.",
     "enableForwardingHelpText": "Enable mod_proxy port forwarding.",
     "disableGroupingGridHelpText": "Disable repository Groups. A complete page reload is required after a change of this value.",
     "allowAnonymousAccessHelpText": "Anonymous users have access on granted repositories.",

scm-ui/ui-webapp/public/locales/en/repos.json

@@ -135,6 +135,12 @@
       "count_plural": "{{count}} Contributors"
     }
   },
+  "commit": {
+    "commitAuthor": {
+      "author": "Author",
+      "noMail": "We have found no email address for your current user. We will use the generated address shown below."
+    }
+  },
   "repositoryForm": {
     "subtitle": "Edit Repository",
     "submit": "Save",

scm-ui/ui-webapp/src/admin/components/form/ConfigForm.tsx

@@ -145,6 +145,7 @@ class ConfigForm extends React.Component<Props, State> {
           skipFailedAuthenticators={config.skipFailedAuthenticators}
           pluginUrl={config.pluginUrl}
           releaseFeedUrl={config.releaseFeedUrl}
+          mailDomainName={config.mailDomainName}
           enabledXsrfProtection={config.enabledXsrfProtection}
           enabledUserConverter={config.enabledUserConverter}
           namespaceStrategy={config.namespaceStrategy}

scm-ui/ui-webapp/src/admin/components/form/GeneralSettings.tsx

@@ -36,6 +36,7 @@ type Props = WithTranslation & {
   skipFailedAuthenticators: boolean;
   pluginUrl: string;
   releaseFeedUrl: string;
+  mailDomainName: string;
   enabledXsrfProtection: boolean;
   enabledUserConverter: boolean;
   namespaceStrategy: string;
@@ -52,6 +53,7 @@ class GeneralSettings extends React.Component<Props> {
       loginInfoUrl,
       pluginUrl,
       releaseFeedUrl,
+      mailDomainName,
       enabledXsrfProtection,
       enabledUserConverter,
       anonymousMode,
@@ -140,6 +142,15 @@ class GeneralSettings extends React.Component<Props> {
               helpText={t("help.releaseFeedUrlHelpText")}
             />
           </div>
+          <div className="column is-half">
+            <InputField
+              label={t("general-settings.mail-domain-name")}
+              onChange={this.handleMailDomainNameChange}
+              value={mailDomainName}
+              disabled={!hasUpdatePermission}
+              helpText={t("help.mailDomainNameHelpText")}
+            />
+          </div>
           <div className="column is-half">
             <Checkbox
               label={t("general-settings.enabled-user-converter")}
@@ -179,6 +190,9 @@ class GeneralSettings extends React.Component<Props> {
   handleReleaseFeedUrlChange = (value: string) => {
     this.props.onChange(true, value, "releaseFeedUrl");
   };
+  handleMailDomainNameChange = (value: string) => {
+    this.props.onChange(true, value, "mailDomainName");
+  };
 }
 
 export default withTranslation("config")(GeneralSettings);

scm-ui/ui-webapp/src/users/components/UserForm.tsx

@@ -264,7 +264,7 @@ class UserForm extends React.Component<Props, State> {
 
   handleEmailChange = (mail: string) => {
     this.setState({
-      mailValidationError: !validator.isMailValid(mail),
+      mailValidationError: !!mail && !validator.isMailValid(mail),
       user: {
         ...this.state.user,
         mail

scm-webapp/src/main/java/sonia/scm/api/v2/resources/ConfigDto.java

@@ -60,6 +60,7 @@ public class ConfigDto extends HalRepresentation {
   private String namespaceStrategy;
   private String loginInfoUrl;
   private String releaseFeedUrl;
+  private String mailDomainName;
 
   @Override
   @SuppressWarnings("squid:S1185") // We want to have this method available in this package

scm-webapp/src/main/java/sonia/scm/api/v2/resources/MeDto.java

@@ -24,6 +24,7 @@
 
 package sonia.scm.api.v2.resources;
 
+import com.fasterxml.jackson.annotation.JsonInclude;
 import de.otto.edison.hal.Embedded;
 import de.otto.edison.hal.HalRepresentation;
 import de.otto.edison.hal.Links;
@@ -40,7 +41,10 @@ public class MeDto extends HalRepresentation {
 
   private String name;
   private String displayName;
+  @JsonInclude(JsonInclude.Include.NON_NULL)
   private String mail;
+  @JsonInclude(JsonInclude.Include.NON_NULL)
+  private String fallbackMail;
   private Set<String> groups;
 
   MeDto(Links links, Embedded embedded) {

scm-webapp/src/main/java/sonia/scm/api/v2/resources/MeDtoFactory.java

@@ -24,12 +24,14 @@
 
 package sonia.scm.api.v2.resources;
 
+import com.google.common.base.Strings;
 import de.otto.edison.hal.Embedded;
 import de.otto.edison.hal.Links;
 import org.apache.shiro.SecurityUtils;
 import org.apache.shiro.subject.PrincipalCollection;
 import org.apache.shiro.subject.Subject;
 import sonia.scm.group.GroupCollector;
+import sonia.scm.user.EMail;
 import sonia.scm.user.User;
 import sonia.scm.user.UserManager;
 import sonia.scm.user.UserPermissions;
@@ -46,12 +48,14 @@ public class MeDtoFactory extends HalAppenderMapper {
   private final ResourceLinks resourceLinks;
   private final UserManager userManager;
   private final GroupCollector groupCollector;
+  private final EMail eMail;
 
   @Inject
-  public MeDtoFactory(ResourceLinks resourceLinks, UserManager userManager, GroupCollector groupCollector) {
+  public MeDtoFactory(ResourceLinks resourceLinks, UserManager userManager, GroupCollector groupCollector, EMail eMail) {
     this.resourceLinks = resourceLinks;
     this.userManager = userManager;
     this.groupCollector = groupCollector;
+    this.eMail = eMail;
   }
 
   public MeDto create() {
@@ -61,6 +65,7 @@ public class MeDtoFactory extends HalAppenderMapper {
     MeDto dto = createDto(user);
     mapUserProperties(user, dto);
     mapGroups(user, dto);
+    setGeneratedMail(user, dto);
     return dto;
   }
 
@@ -79,6 +84,12 @@ public class MeDtoFactory extends HalAppenderMapper {
     return subject.getPrincipals();
   }
 
+  private void setGeneratedMail(User user, MeDto dto) {
+    if (Strings.isNullOrEmpty(user.getMail())) {
+      dto.setFallbackMail(eMail.getMailOrFallback(user));
+    }
+  }
+
 
   private MeDto createDto(User user) {
     Links.Builder linksBuilder = linkingTo().self(resourceLinks.me().self());

scm-webapp/src/main/java/sonia/scm/api/v2/resources/UserDto.java

@@ -47,7 +47,8 @@ public class UserDto extends HalRepresentation {
   private String displayName;
   @JsonInclude(JsonInclude.Include.NON_NULL)
   private Instant lastModified;
-  @NotEmpty @Email
+  @JsonInclude(JsonInclude.Include.NON_NULL)
+  @Email
   private String mail;
   @Pattern(regexp = ValidationUtil.REGEX_NAME)
   private String name;

scm-webapp/src/test/java/sonia/scm/api/v2/resources/ConfigDtoToScmConfigurationMapperTest.java

@@ -75,6 +75,7 @@ public class ConfigDtoToScmConfigurationMapperTest {
     assertFalse(config.isEnabledUserConverter());
     assertEquals("username", config.getNamespaceStrategy());
     assertEquals("https://scm-manager.org/login-info", config.getLoginInfoUrl());
+    assertEquals("hitchhiker.mail", config.getMailDomainName());
   }
 
   @Test
@@ -113,6 +114,7 @@ public class ConfigDtoToScmConfigurationMapperTest {
     configDto.setEnabledXsrfProtection(true);
     configDto.setNamespaceStrategy("username");
     configDto.setLoginInfoUrl("https://scm-manager.org/login-info");
+    configDto.setMailDomainName("hitchhiker.mail");
     configDto.setEnabledUserConverter(false);
 
     return configDto;

scm-webapp/src/test/java/sonia/scm/api/v2/resources/MeDtoFactoryTest.java

@@ -38,9 +38,9 @@ import org.mockito.junit.jupiter.MockitoSettings;
 import org.mockito.quality.Strictness;
 import sonia.scm.SCMContext;
 import sonia.scm.group.GroupCollector;
+import sonia.scm.user.EMail;
 import sonia.scm.user.User;
 import sonia.scm.user.UserManager;
-import sonia.scm.user.UserPermissions;
 import sonia.scm.user.UserTestData;
 
 import java.net.URI;
@@ -65,13 +65,16 @@ class MeDtoFactoryTest {
   @Mock
   private Subject subject;
 
+  @Mock
+  private EMail eMail;
+
   private MeDtoFactory meDtoFactory;
 
   @BeforeEach
   void setUpContext() {
     ThreadContext.bind(subject);
     ResourceLinks resourceLinks = ResourceLinksMock.createMock(baseUri);
-    meDtoFactory = new MeDtoFactory(resourceLinks, userManager, groupCollector);
+    meDtoFactory = new MeDtoFactory(resourceLinks, userManager, groupCollector, eMail);
   }
 
   @AfterEach
@@ -235,4 +238,17 @@ class MeDtoFactoryTest {
     MeDto dto = meDtoFactory.create();
     assertThat(dto.getLinks().getLinkBy("profile").get().getHref()).isEqualTo("http://hitchhiker.com/users/trillian");
   }
+
+  @Test
+  void shouldUserGeneratedMailOnlyWhenUserHasNone() {
+    User user = UserTestData.createTrillian();
+    user.setMail(null);
+    prepareSubject(user);
+    when(eMail.getMailOrFallback(user)).thenReturn("trillian@hitchhiker.local");
+
+    MeDto dto = meDtoFactory.create();
+
+    assertThat(dto.getMail()).isNull();
+    assertThat(dto.getFallbackMail()).isEqualTo("trillian@hitchhiker.local");
+  }
 }

scm-webapp/src/test/java/sonia/scm/api/v2/resources/ScmConfigurationToConfigDtoMapperTest.java

@@ -106,6 +106,7 @@ public class ScmConfigurationToConfigDtoMapperTest {
     assertEquals("username", dto.getNamespaceStrategy());
     assertEquals("https://scm-manager.org/login-info", dto.getLoginInfoUrl());
     assertEquals("https://www.scm-manager.org/download/rss.xml", dto.getReleaseFeedUrl());
+    assertEquals("scm-manager.local", dto.getMailDomainName());
 
     assertEquals(expectedBaseUri.toString(), dto.getLinks().getLinkBy("self").get().getHref());
     assertEquals(expectedBaseUri.toString(), dto.getLinks().getLinkBy("update").get().getHref());