Keep file attributes on modification

CHANGELOG.md

@@ -17,6 +17,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 - Modification for mercurial repositories with enabled XSRF protection
 - Does not throw NullPointerException when merge fails without normal merge conflicts
+- Keep file attributes on modification
 
 ### Removed
 - Enunciate rest documentation

scm-core/src/main/java/sonia/scm/repository/spi/ModifyWorkerHelper.java

@@ -1,6 +1,8 @@
 package sonia.scm.repository.spi;
 
 import org.apache.commons.lang.StringUtils;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 import sonia.scm.ContextEntry;
 import sonia.scm.repository.Repository;
 
@@ -10,8 +12,13 @@ import java.nio.file.FileAlreadyExistsException;
 import java.nio.file.Files;
 import java.nio.file.NoSuchFileException;
 import java.nio.file.Path;
+import java.nio.file.attribute.PosixFilePermission;
+import java.util.Optional;
+import java.util.Set;
 
 import static java.nio.file.StandardCopyOption.REPLACE_EXISTING;
+import static java.util.Optional.empty;
+import static java.util.Optional.of;
 import static sonia.scm.AlreadyExistsException.alreadyExists;
 import static sonia.scm.ContextEntry.ContextBuilder.entity;
 import static sonia.scm.NotFoundException.notFound;
@@ -22,6 +29,8 @@ import static sonia.scm.NotFoundException.notFound;
  */
 public interface ModifyWorkerHelper extends ModifyCommand.Worker {
 
+  Logger LOG = LoggerFactory.getLogger(ModifyWorkerHelper.class);
+
   @Override
   default void delete(String toBeDeleted) throws IOException {
     Path fileToBeDeleted = new File(getWorkDir(), toBeDeleted).toPath();
@@ -57,10 +66,34 @@ public interface ModifyWorkerHelper extends ModifyCommand.Worker {
     if (!targetFile.toFile().exists()) {
       throw notFound(createFileContext(path));
     }
+    Optional<Set<PosixFilePermission>> posixFilePermissions = getPosixFilePermissions(targetFile);
     Files.move(file.toPath(), targetFile, REPLACE_EXISTING);
+    posixFilePermissions.ifPresent(permissions -> setPosixFilePermissions(targetFile, permissions));
     addFileToScm(path, targetFile);
   }
 
+  default Optional<Set<PosixFilePermission>> getPosixFilePermissions(Path targetFile) {
+    try {
+      return of(Files.getPosixFilePermissions(targetFile));
+    } catch (UnsupportedOperationException e) {
+      LOG.trace("posix file permissions not supported");
+      return empty();
+    } catch (IOException e) {
+      LOG.info("could not read posix file permissions for file {}", targetFile);
+      return empty();
+    }
+  }
+
+  default void setPosixFilePermissions(Path targetFile, Set<PosixFilePermission> permissions) {
+    try {
+      Files.setPosixFilePermissions(targetFile, permissions);
+    } catch (UnsupportedOperationException e) {
+      LOG.trace("posix file permissions not supported");
+    } catch (IOException e) {
+      LOG.info("could not write posix file permissions to file {}", targetFile);
+    }
+  }
+
   void addFileToScm(String name, Path file);
 
   default ContextEntry.ContextBuilder createFileContext(String path) {

scm-core/src/test/java/sonia/scm/repository/spi/ModifyWorkerHelperTest.java

@@ -0,0 +1,90 @@
+package sonia.scm.repository.spi;
+
+import com.google.common.collect.ImmutableSet;
+import org.assertj.core.api.Assumptions;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.junitpioneer.jupiter.TempDirectory;
+import sonia.scm.repository.Repository;
+
+import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+
+import static java.nio.file.attribute.PosixFilePermission.GROUP_EXECUTE;
+import static java.nio.file.attribute.PosixFilePermission.GROUP_READ;
+import static java.nio.file.attribute.PosixFilePermission.OTHERS_EXECUTE;
+import static java.nio.file.attribute.PosixFilePermission.OTHERS_READ;
+import static java.nio.file.attribute.PosixFilePermission.OWNER_EXECUTE;
+import static java.nio.file.attribute.PosixFilePermission.OWNER_READ;
+import static java.nio.file.attribute.PosixFilePermission.OWNER_WRITE;
+import static org.assertj.core.api.Assertions.assertThat;
+
+@ExtendWith(TempDirectory.class)
+class ModifyWorkerHelperTest {
+
+  @Test
+  void shouldKeepExecutableFlag(@TempDirectory.TempDir Path temp) throws IOException {
+
+    File target = createFile(temp, "executable.sh");
+    File newFile = createFile(temp, "other");
+
+    Assumptions.assumeThatThrownBy(() -> {
+      Files.setPosixFilePermissions(target.toPath(),
+        ImmutableSet.of(OWNER_READ, OWNER_WRITE, OWNER_EXECUTE, GROUP_READ, GROUP_EXECUTE, OTHERS_READ, OTHERS_EXECUTE));
+      Files.setPosixFilePermissions(newFile.toPath(),
+        ImmutableSet.of(OWNER_READ, OWNER_WRITE, GROUP_READ, OTHERS_READ));
+    }).doesNotThrowAnyException(); // ignore this test on systems that does not support posix file permissions
+
+    ModifyWorkerHelper helper = new MinimalModifyWorkerHelper(temp);
+
+    helper.modify("executable.sh", newFile);
+
+    assertThat(Files.getPosixFilePermissions(target.toPath()))
+      .contains(OWNER_READ, OWNER_WRITE, OWNER_EXECUTE, GROUP_READ, GROUP_EXECUTE, OTHERS_READ, OTHERS_EXECUTE);
+  }
+
+  private File createFile(Path temp, String fileName) throws IOException {
+    File file = new File(temp.toFile(), fileName);
+    FileWriter source = new FileWriter(file);
+    source.write("something");
+    source.close();
+    return file;
+  }
+
+  private static class MinimalModifyWorkerHelper implements ModifyWorkerHelper {
+
+    private final Path temp;
+
+    public MinimalModifyWorkerHelper(Path temp) {
+      this.temp = temp;
+    }
+
+    @Override
+    public void doScmDelete(String toBeDeleted) {
+
+    }
+
+    @Override
+    public void addFileToScm(String name, Path file) {
+
+    }
+
+    @Override
+    public File getWorkDir() {
+      return temp.toFile();
+    }
+
+    @Override
+    public Repository getRepository() {
+      return null;
+    }
+
+    @Override
+    public String getBranch() {
+      return null;
+    }
+  }
+}