From 7900b94011f6afaa5c60034ed08583e330d837fb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9=20Pfeuffer?= <rene.pfeuffer@cloudogu.com>
Date: Wed, 5 Dec 2018 13:52:14 +0100
Subject: [PATCH 01/20] Add resource for merges

---
 .../repository/api/MergeCommandBuilder.java   |   4 +-
 .../scm/repository/api/RepositoryService.java |   4 +-
 .../main/java/sonia/scm/web/VndMediaType.java |   2 +
 .../scm/api/v2/resources/MapperModule.java    |   2 +
 .../scm/api/v2/resources/MergeCommandDto.java |  14 ++
 .../scm/api/v2/resources/MergeResource.java   |  71 +++++++++
 .../scm/api/v2/resources/MergeResultDto.java  |  12 ++
 .../v2/resources/MergeResultToDtoMapper.java  |   9 ++
 .../api/v2/resources/RepositoryResource.java  |  12 +-
 .../api/v2/resources/MergeResourceTest.java   | 150 ++++++++++++++++++
 .../api/v2/resources/RepositoryTestBase.java  |   4 +-
 .../sonia/scm/api/v2/mergeCommand.json        |   4 +
 .../scm/api/v2/mergeCommand_invalid.json      |   4 +
 13 files changed, 283 insertions(+), 9 deletions(-)
 create mode 100644 scm-webapp/src/main/java/sonia/scm/api/v2/resources/MergeCommandDto.java
 create mode 100644 scm-webapp/src/main/java/sonia/scm/api/v2/resources/MergeResource.java
 create mode 100644 scm-webapp/src/main/java/sonia/scm/api/v2/resources/MergeResultDto.java
 create mode 100644 scm-webapp/src/main/java/sonia/scm/api/v2/resources/MergeResultToDtoMapper.java
 create mode 100644 scm-webapp/src/test/java/sonia/scm/api/v2/resources/MergeResourceTest.java
 create mode 100644 scm-webapp/src/test/resources/sonia/scm/api/v2/mergeCommand.json
 create mode 100644 scm-webapp/src/test/resources/sonia/scm/api/v2/mergeCommand_invalid.json

diff --git a/scm-core/src/main/java/sonia/scm/repository/api/MergeCommandBuilder.java b/scm-core/src/main/java/sonia/scm/repository/api/MergeCommandBuilder.java
index 881a374864..8fcfc937e5 100644
--- a/scm-core/src/main/java/sonia/scm/repository/api/MergeCommandBuilder.java
+++ b/scm-core/src/main/java/sonia/scm/repository/api/MergeCommandBuilder.java
@@ -15,7 +15,7 @@ import sonia.scm.repository.spi.MergeCommandRequest;
  *
  * To actually merge <code>feature_branch</code> into <code>integration_branch</code> do this:
  * <pre><code>
- *     repositoryService.gerMergeCommand()
+ *     repositoryService.getMergeCommand()
  *       .setBranchToMerge("feature_branch")
  *       .setTargetBranch("integration_branch")
  *       .executeMerge();
@@ -33,7 +33,7 @@ import sonia.scm.repository.spi.MergeCommandRequest;
  *
  * To check whether they can be merged without conflicts beforehand do this:
  * <pre><code>
- *     repositoryService.gerMergeCommand()
+ *     repositoryService.getMergeCommand()
  *       .setBranchToMerge("feature_branch")
  *       .setTargetBranch("integration_branch")
  *       .dryRun()
diff --git a/scm-core/src/main/java/sonia/scm/repository/api/RepositoryService.java b/scm-core/src/main/java/sonia/scm/repository/api/RepositoryService.java
index fe0529e6b5..c76fe524fd 100644
--- a/scm-core/src/main/java/sonia/scm/repository/api/RepositoryService.java
+++ b/scm-core/src/main/java/sonia/scm/repository/api/RepositoryService.java
@@ -363,8 +363,8 @@ public final class RepositoryService implements Closeable {
    *                                      by the implementation of the repository service provider.
    * @since 2.0.0
    */
-  public MergeCommandBuilder gerMergeCommand() {
-    logger.debug("create unbundle command for repository {}",
+  public MergeCommandBuilder getMergeCommand() {
+    logger.debug("create merge command for repository {}",
       repository.getNamespaceAndName());
 
     return new MergeCommandBuilder(provider.getMergeCommand());
diff --git a/scm-core/src/main/java/sonia/scm/web/VndMediaType.java b/scm-core/src/main/java/sonia/scm/web/VndMediaType.java
index e2a2218d34..2a409482c8 100644
--- a/scm-core/src/main/java/sonia/scm/web/VndMediaType.java
+++ b/scm-core/src/main/java/sonia/scm/web/VndMediaType.java
@@ -41,6 +41,8 @@ public class VndMediaType {
   public static final String PASSWORD_CHANGE = PREFIX + "passwordChange" + SUFFIX;
   @SuppressWarnings("squid:S2068")
   public static final String PASSWORD_OVERWRITE = PREFIX + "passwordOverwrite" + SUFFIX;
+  public static final String MERGE_RESULT = PREFIX + "mergeResult" + SUFFIX;
+  public static final String MERGE_COMMAND = PREFIX + "mergeCommand" + SUFFIX;
 
   public static final String ME = PREFIX + "me" + SUFFIX;
   public static final String SOURCE = PREFIX + "source" + SUFFIX;
diff --git a/scm-webapp/src/main/java/sonia/scm/api/v2/resources/MapperModule.java b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/MapperModule.java
index e6cf6721a5..66eadaad7d 100644
--- a/scm-webapp/src/main/java/sonia/scm/api/v2/resources/MapperModule.java
+++ b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/MapperModule.java
@@ -43,6 +43,8 @@ public class MapperModule extends AbstractModule {
     bind(ScmViolationExceptionToErrorDtoMapper.class).to(Mappers.getMapper(ScmViolationExceptionToErrorDtoMapper.class).getClass());
     bind(ExceptionWithContextToErrorDtoMapper.class).to(Mappers.getMapper(ExceptionWithContextToErrorDtoMapper.class).getClass());
 
+    bind(MergeResultToDtoMapper.class).to(Mappers.getMapper(MergeResultToDtoMapper.class).getClass());
+
     // no mapstruct required
     bind(UIPluginDtoMapper.class);
     bind(UIPluginDtoCollectionMapper.class);
diff --git a/scm-webapp/src/main/java/sonia/scm/api/v2/resources/MergeCommandDto.java b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/MergeCommandDto.java
new file mode 100644
index 0000000000..0661d6a4ef
--- /dev/null
+++ b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/MergeCommandDto.java
@@ -0,0 +1,14 @@
+package sonia.scm.api.v2.resources;
+
+import lombok.Getter;
+import lombok.Setter;
+import org.hibernate.validator.constraints.NotEmpty;
+
+@Getter @Setter
+public class MergeCommandDto {
+
+  @NotEmpty
+  private String sourceRevision;
+  @NotEmpty
+  private String targetRevision;
+}
diff --git a/scm-webapp/src/main/java/sonia/scm/api/v2/resources/MergeResource.java b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/MergeResource.java
new file mode 100644
index 0000000000..5af32cedad
--- /dev/null
+++ b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/MergeResource.java
@@ -0,0 +1,71 @@
+package sonia.scm.api.v2.resources;
+
+import lombok.extern.slf4j.Slf4j;
+import org.apache.http.HttpStatus;
+import sonia.scm.repository.NamespaceAndName;
+import sonia.scm.repository.api.MergeCommandBuilder;
+import sonia.scm.repository.api.MergeCommandResult;
+import sonia.scm.repository.api.MergeDryRunCommandResult;
+import sonia.scm.repository.api.RepositoryService;
+import sonia.scm.repository.api.RepositoryServiceFactory;
+import sonia.scm.web.VndMediaType;
+
+import javax.inject.Inject;
+import javax.validation.Valid;
+import javax.ws.rs.Consumes;
+import javax.ws.rs.POST;
+import javax.ws.rs.Path;
+import javax.ws.rs.PathParam;
+import javax.ws.rs.Produces;
+import javax.ws.rs.core.Response;
+
+@Slf4j
+public class MergeResource {
+
+  private final RepositoryServiceFactory serviceFactory;
+  private final MergeResultToDtoMapper mapper;
+
+  @Inject
+  public MergeResource(RepositoryServiceFactory serviceFactory, MergeResultToDtoMapper mapper) {
+    this.serviceFactory = serviceFactory;
+    this.mapper = mapper;
+  }
+
+  @POST
+  @Produces(VndMediaType.MERGE_RESULT)
+  @Consumes(VndMediaType.MERGE_COMMAND)
+  public Response merge(@PathParam("namespace") String namespace, @PathParam("name") String name, @Valid MergeCommandDto mergeCommand) {
+    NamespaceAndName namespaceAndName = new NamespaceAndName(namespace, name);
+    log.info("Merge in Repository {}/{} from {} to {}", namespace, name, mergeCommand.getSourceRevision(), mergeCommand.getTargetRevision());
+    try (RepositoryService repositoryService = serviceFactory.create(namespaceAndName)) {
+      MergeCommandResult mergeCommandResult = createMergeCommand(mergeCommand, repositoryService).executeMerge();
+      if (mergeCommandResult.isSuccess()) {
+        return Response.noContent().build();
+      } else {
+        return Response.status(HttpStatus.SC_CONFLICT).entity(mapper.map(mergeCommandResult)).build();
+      }
+    }
+  }
+
+  @POST
+  @Path("dry-run/")
+  public Response dryRun(@PathParam("namespace") String namespace, @PathParam("name") String name, @Valid MergeCommandDto mergeCommand) {
+    NamespaceAndName namespaceAndName = new NamespaceAndName(namespace, name);
+    log.info("Merge in Repository {}/{} from {} to {}", namespace, name, mergeCommand.getSourceRevision(), mergeCommand.getTargetRevision());
+    try (RepositoryService repositoryService = serviceFactory.create(namespaceAndName)) {
+      MergeDryRunCommandResult mergeCommandResult = createMergeCommand(mergeCommand, repositoryService).dryRun();
+      if (mergeCommandResult.isMergeable()) {
+        return Response.noContent().build();
+      } else {
+        return Response.status(HttpStatus.SC_CONFLICT).build();
+      }
+    }
+  }
+
+  private MergeCommandBuilder createMergeCommand(MergeCommandDto mergeCommand, RepositoryService repositoryService) {
+    return repositoryService
+      .getMergeCommand()
+      .setBranchToMerge(mergeCommand.getSourceRevision())
+      .setTargetBranch(mergeCommand.getTargetRevision());
+  }
+}
diff --git a/scm-webapp/src/main/java/sonia/scm/api/v2/resources/MergeResultDto.java b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/MergeResultDto.java
new file mode 100644
index 0000000000..fa523153cf
--- /dev/null
+++ b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/MergeResultDto.java
@@ -0,0 +1,12 @@
+package sonia.scm.api.v2.resources;
+
+import lombok.Getter;
+import lombok.Setter;
+
+import java.util.Collection;
+
+@Getter
+@Setter
+public class MergeResultDto {
+  private Collection<String> filesWithConflict;
+}
diff --git a/scm-webapp/src/main/java/sonia/scm/api/v2/resources/MergeResultToDtoMapper.java b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/MergeResultToDtoMapper.java
new file mode 100644
index 0000000000..1dbbe8aacd
--- /dev/null
+++ b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/MergeResultToDtoMapper.java
@@ -0,0 +1,9 @@
+package sonia.scm.api.v2.resources;
+
+import org.mapstruct.Mapper;
+import sonia.scm.repository.api.MergeCommandResult;
+
+@Mapper
+public interface MergeResultToDtoMapper {
+  MergeResultDto map(MergeCommandResult result);
+}
diff --git a/scm-webapp/src/main/java/sonia/scm/api/v2/resources/RepositoryResource.java b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/RepositoryResource.java
index f65235db0b..c4f76d0167 100644
--- a/scm-webapp/src/main/java/sonia/scm/api/v2/resources/RepositoryResource.java
+++ b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/RepositoryResource.java
@@ -10,7 +10,6 @@ import sonia.scm.repository.RepositoryManager;
 import sonia.scm.web.VndMediaType;
 
 import javax.inject.Inject;
-import javax.inject.Named;
 import javax.inject.Provider;
 import javax.validation.Valid;
 import javax.ws.rs.Consumes;
@@ -44,6 +43,7 @@ public class RepositoryResource {
   private final Provider<DiffRootResource> diffRootResource;
   private final Provider<ModificationsRootResource> modificationsRootResource;
   private final Provider<FileHistoryRootResource> fileHistoryRootResource;
+  private final Provider<MergeResource> mergeResource;
 
   @Inject
   public RepositoryResource(
@@ -56,8 +56,8 @@ public class RepositoryResource {
     Provider<PermissionRootResource> permissionRootResource,
     Provider<DiffRootResource> diffRootResource,
     Provider<ModificationsRootResource> modificationsRootResource,
-    Provider<FileHistoryRootResource> fileHistoryRootResource
-  ) {
+    Provider<FileHistoryRootResource> fileHistoryRootResource,
+    Provider<MergeResource> mergeResource) {
     this.dtoToRepositoryMapper = dtoToRepositoryMapper;
     this.manager = manager;
     this.repositoryToDtoMapper = repositoryToDtoMapper;
@@ -71,6 +71,7 @@ public class RepositoryResource {
     this.diffRootResource = diffRootResource;
     this.modificationsRootResource = modificationsRootResource;
     this.fileHistoryRootResource = fileHistoryRootResource;
+    this.mergeResource = mergeResource;
   }
 
   /**
@@ -194,9 +195,12 @@ public class RepositoryResource {
     return permissionRootResource.get();
   }
 
- @Path("modifications/")
+  @Path("modifications/")
   public ModificationsRootResource modifications() {return modificationsRootResource.get(); }
 
+  @Path("merge/")
+  public MergeResource merge() {return mergeResource.get(); }
+
   private Optional<Response> handleNotArchived(Throwable throwable) {
     if (throwable instanceof RepositoryIsNotArchivedException) {
       return Optional.of(Response.status(Response.Status.PRECONDITION_FAILED).build());
diff --git a/scm-webapp/src/test/java/sonia/scm/api/v2/resources/MergeResourceTest.java b/scm-webapp/src/test/java/sonia/scm/api/v2/resources/MergeResourceTest.java
new file mode 100644
index 0000000000..d47ff35e5f
--- /dev/null
+++ b/scm-webapp/src/test/java/sonia/scm/api/v2/resources/MergeResourceTest.java
@@ -0,0 +1,150 @@
+package sonia.scm.api.v2.resources;
+
+import com.google.common.io.Resources;
+import com.google.inject.util.Providers;
+import org.jboss.resteasy.core.Dispatcher;
+import org.jboss.resteasy.mock.MockHttpRequest;
+import org.jboss.resteasy.mock.MockHttpResponse;
+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.mockito.InjectMocks;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+import sonia.scm.repository.NamespaceAndName;
+import sonia.scm.repository.api.MergeCommandBuilder;
+import sonia.scm.repository.api.MergeCommandResult;
+import sonia.scm.repository.api.MergeDryRunCommandResult;
+import sonia.scm.repository.api.RepositoryService;
+import sonia.scm.repository.api.RepositoryServiceFactory;
+import sonia.scm.repository.spi.MergeCommand;
+import sonia.scm.web.VndMediaType;
+
+import java.net.URL;
+
+import static java.util.Arrays.asList;
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.when;
+
+@ExtendWith(MockitoExtension.class)
+public class MergeResourceTest extends RepositoryTestBase {
+
+  public static final String MERGE_URL = "/" + RepositoryRootResource.REPOSITORIES_PATH_V2 + "space/repo/merge/";
+
+  private Dispatcher dispatcher;
+  @Mock
+  private RepositoryServiceFactory serviceFactory;
+  @Mock
+  private RepositoryService repositoryService;
+  @Mock
+  private MergeCommand mergeCommand;
+  @InjectMocks
+  private MergeCommandBuilder mergeCommandBuilder;
+  private MergeResultToDtoMapperImpl mapper = new MergeResultToDtoMapperImpl();
+
+  private MergeResource mergeResource;
+
+  @BeforeEach
+  void init() {
+    mergeResource = new MergeResource(serviceFactory, mapper);
+    super.mergeResource = Providers.of(mergeResource);
+    dispatcher = DispatcherMock.createDispatcher(getRepositoryRootResource());
+  }
+
+  @Test
+  void shouldHandleIllegalInput() throws Exception {
+    URL url = Resources.getResource("sonia/scm/api/v2/mergeCommand_invalid.json");
+    byte[] mergeCommandJson = Resources.toByteArray(url);
+
+    MockHttpRequest request = MockHttpRequest
+      .post(MERGE_URL + "dry-run/")
+      .content(mergeCommandJson)
+      .contentType(VndMediaType.MERGE_COMMAND);
+    MockHttpResponse response = new MockHttpResponse();
+    dispatcher.invoke(request, response);
+
+    assertThat(response.getStatus()).isEqualTo(400);
+    System.out.println(response.getContentAsString());
+  }
+
+  @Nested
+  class ExecutingMergeCommand {
+
+    @BeforeEach
+    void initRepository() {
+      when(serviceFactory.create(new NamespaceAndName("space", "repo"))).thenReturn(repositoryService);
+      when(repositoryService.getMergeCommand()).thenReturn(mergeCommandBuilder);
+    }
+
+    @Test
+    void shouldHandleSuccessfulMerge() throws Exception {
+      when(mergeCommand.merge(any())).thenReturn(MergeCommandResult.success());
+
+      URL url = Resources.getResource("sonia/scm/api/v2/mergeCommand.json");
+      byte[] mergeCommandJson = Resources.toByteArray(url);
+
+      MockHttpRequest request = MockHttpRequest
+        .post(MERGE_URL)
+        .content(mergeCommandJson)
+        .contentType(VndMediaType.MERGE_COMMAND);
+      MockHttpResponse response = new MockHttpResponse();
+      dispatcher.invoke(request, response);
+
+      assertThat(response.getStatus()).isEqualTo(204);
+    }
+
+    @Test
+    void shouldHandleFailedMerge() throws Exception {
+      when(mergeCommand.merge(any())).thenReturn(MergeCommandResult.failure(asList("file1", "file2")));
+
+      URL url = Resources.getResource("sonia/scm/api/v2/mergeCommand.json");
+      byte[] mergeCommandJson = Resources.toByteArray(url);
+
+      MockHttpRequest request = MockHttpRequest
+        .post(MERGE_URL)
+        .content(mergeCommandJson)
+        .contentType(VndMediaType.MERGE_COMMAND);
+      MockHttpResponse response = new MockHttpResponse();
+      dispatcher.invoke(request, response);
+
+      assertThat(response.getStatus()).isEqualTo(409);
+      assertThat(response.getContentAsString()).contains("file1", "file2");
+    }
+
+    @Test
+    void shouldHandleSuccessfulDryRun() throws Exception {
+      when(mergeCommand.dryRun(any())).thenReturn(new MergeDryRunCommandResult(true));
+
+      URL url = Resources.getResource("sonia/scm/api/v2/mergeCommand.json");
+      byte[] mergeCommandJson = Resources.toByteArray(url);
+
+      MockHttpRequest request = MockHttpRequest
+        .post(MERGE_URL + "dry-run/")
+        .content(mergeCommandJson)
+        .contentType(VndMediaType.MERGE_COMMAND);
+      MockHttpResponse response = new MockHttpResponse();
+      dispatcher.invoke(request, response);
+
+      assertThat(response.getStatus()).isEqualTo(204);
+    }
+
+    @Test
+    void shouldHandleFailedDryRun() throws Exception {
+      when(mergeCommand.dryRun(any())).thenReturn(new MergeDryRunCommandResult(false));
+
+      URL url = Resources.getResource("sonia/scm/api/v2/mergeCommand.json");
+      byte[] mergeCommandJson = Resources.toByteArray(url);
+
+      MockHttpRequest request = MockHttpRequest
+        .post(MERGE_URL + "dry-run/")
+        .content(mergeCommandJson)
+        .contentType(VndMediaType.MERGE_COMMAND);
+      MockHttpResponse response = new MockHttpResponse();
+      dispatcher.invoke(request, response);
+
+      assertThat(response.getStatus()).isEqualTo(409);
+    }
+  }
+}
diff --git a/scm-webapp/src/test/java/sonia/scm/api/v2/resources/RepositoryTestBase.java b/scm-webapp/src/test/java/sonia/scm/api/v2/resources/RepositoryTestBase.java
index 3d3b28ae51..0ccb923e45 100644
--- a/scm-webapp/src/test/java/sonia/scm/api/v2/resources/RepositoryTestBase.java
+++ b/scm-webapp/src/test/java/sonia/scm/api/v2/resources/RepositoryTestBase.java
@@ -21,6 +21,7 @@ public abstract class RepositoryTestBase {
   protected Provider<ModificationsRootResource> modificationsRootResource;
   protected Provider<FileHistoryRootResource> fileHistoryRootResource;
   protected Provider<RepositoryCollectionResource> repositoryCollectionResource;
+  protected Provider<MergeResource> mergeResource;
 
 
   RepositoryRootResource getRepositoryRootResource() {
@@ -36,7 +37,8 @@ public abstract class RepositoryTestBase {
       permissionRootResource,
       diffRootResource,
       modificationsRootResource,
-      fileHistoryRootResource)), repositoryCollectionResource);
+      fileHistoryRootResource,
+      mergeResource)), repositoryCollectionResource);
   }
 
 
diff --git a/scm-webapp/src/test/resources/sonia/scm/api/v2/mergeCommand.json b/scm-webapp/src/test/resources/sonia/scm/api/v2/mergeCommand.json
new file mode 100644
index 0000000000..dde0b6a413
--- /dev/null
+++ b/scm-webapp/src/test/resources/sonia/scm/api/v2/mergeCommand.json
@@ -0,0 +1,4 @@
+{
+  "sourceRevision": "source",
+  "targetRevision": "target"
+}
diff --git a/scm-webapp/src/test/resources/sonia/scm/api/v2/mergeCommand_invalid.json b/scm-webapp/src/test/resources/sonia/scm/api/v2/mergeCommand_invalid.json
new file mode 100644
index 0000000000..b2d1e5ab3f
--- /dev/null
+++ b/scm-webapp/src/test/resources/sonia/scm/api/v2/mergeCommand_invalid.json
@@ -0,0 +1,4 @@
+{
+  "sourceRevision": "",
+  "targetRevision": "target"
+}

From 8c9e38e395d8a12eaf0cce2abe27767756f8782e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9=20Pfeuffer?= <rene.pfeuffer@cloudogu.com>
Date: Wed, 5 Dec 2018 15:32:30 +0100
Subject: [PATCH 02/20] Secure merge command

---
 .../main/java/sonia/scm/repository/spi/GitMergeCommand.java    | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java b/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java
index 5e9eac5230..26f8ad4a42 100644
--- a/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java
+++ b/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java
@@ -15,6 +15,7 @@ import org.slf4j.LoggerFactory;
 import sonia.scm.repository.GitWorkdirFactory;
 import sonia.scm.repository.InternalRepositoryException;
 import sonia.scm.repository.Person;
+import sonia.scm.repository.RepositoryPermissions;
 import sonia.scm.repository.api.MergeCommandResult;
 import sonia.scm.repository.api.MergeDryRunCommandResult;
 import sonia.scm.user.User;
@@ -40,6 +41,8 @@ public class GitMergeCommand extends AbstractGitCommand implements MergeCommand
 
   @Override
   public MergeCommandResult merge(MergeCommandRequest request) {
+    RepositoryPermissions.permissionWrite(context.getRepository().getId()).check();
+
     try (WorkingCopy workingCopy = workdirFactory.createWorkingCopy(context)) {
       Repository repository = workingCopy.get();
       logger.debug("cloned repository to folder {}", repository.getWorkTree());

From 9a3b8c26fbaad2026126c498e8704a5061d7a93d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9=20Pfeuffer?= <rene.pfeuffer@cloudogu.com>
Date: Wed, 5 Dec 2018 16:01:34 +0100
Subject: [PATCH 03/20] Fix unit test

---
 .../sonia/scm/repository/spi/GitMergeCommandTest.java    | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitMergeCommandTest.java b/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitMergeCommandTest.java
index 1fca7814ed..2923d445ac 100644
--- a/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitMergeCommandTest.java
+++ b/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitMergeCommandTest.java
@@ -19,7 +19,7 @@ import java.io.IOException;
 
 import static org.assertj.core.api.Assertions.assertThat;
 
-@SubjectAware(configuration = "classpath:sonia/scm/configuration/shiro.ini")
+@SubjectAware(configuration = "classpath:sonia/scm/configuration/shiro.ini", username = "admin", password = "secret")
 public class GitMergeCommandTest extends AbstractGitCommandTestBase {
 
   private static final String REALM = "AdminRealm";
@@ -111,11 +111,14 @@ public class GitMergeCommandTest extends AbstractGitCommandTestBase {
   }
 
   @Test
-  @SubjectAware(username = "admin", password = "secret")
   public void shouldTakeAuthorFromSubjectIfNotSet() throws IOException, GitAPIException {
+    SimplePrincipalCollection principals = new SimplePrincipalCollection();
+    principals.add("admin", REALM);
+    principals.add( new User("dirk", "Dirk Gently", "dirk@holistic.det"), REALM);
     shiro.setSubject(
       new Subject.Builder()
-        .principals(new SimplePrincipalCollection(new User("dirk", "Dirk Gently", "dirk@holistic.det"), REALM))
+        .principals(principals)
+        .authenticated(true)
         .buildSubject());
     GitMergeCommand command = createCommand();
     MergeCommandRequest request = new MergeCommandRequest();

From 35f73cdc188a1b1a722dcb1f66fb41a9624b78ea Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9=20Pfeuffer?= <rene.pfeuffer@cloudogu.com>
Date: Wed, 5 Dec 2018 16:09:38 +0100
Subject: [PATCH 04/20] Do not commit empty merges

---
 .../scm/repository/spi/GitMergeCommand.java   | 10 +++++---
 .../repository/spi/GitMergeCommandTest.java   | 25 +++++++++++++++++++
 2 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java b/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java
index 26f8ad4a42..888fef5b65 100644
--- a/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java
+++ b/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java
@@ -116,10 +116,12 @@ public class GitMergeCommand extends AbstractGitCommand implements MergeCommand
       logger.debug("merged branch {} into {}", toMerge, target);
       Person authorToUse = determineAuthor();
       try {
-        clone.commit()
-          .setAuthor(authorToUse.getName(), authorToUse.getMail())
-          .setMessage(MessageFormat.format(determineMessageTemplate(), toMerge, target))
-          .call();
+        if (!clone.status().call().isClean()) {
+          clone.commit()
+            .setAuthor(authorToUse.getName(), authorToUse.getMail())
+            .setMessage(MessageFormat.format(determineMessageTemplate(), toMerge, target))
+            .call();
+        }
       } catch (GitAPIException e) {
         throw new InternalRepositoryException(context.getRepository(), "could not commit merge between branch " + toMerge + " and " + target, e);
       }
diff --git a/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitMergeCommandTest.java b/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitMergeCommandTest.java
index 2923d445ac..380619dfa5 100644
--- a/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitMergeCommandTest.java
+++ b/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitMergeCommandTest.java
@@ -6,6 +6,7 @@ import org.apache.shiro.subject.SimplePrincipalCollection;
 import org.apache.shiro.subject.Subject;
 import org.eclipse.jgit.api.Git;
 import org.eclipse.jgit.api.errors.GitAPIException;
+import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.PersonIdent;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.revwalk.RevCommit;
@@ -77,6 +78,30 @@ public class GitMergeCommandTest extends AbstractGitCommandTestBase {
     assertThat(new String(contentOfFileB)).isEqualTo("b\ncontent from branch\n");
   }
 
+  @Test
+  public void shouldNotMergeTwice() throws IOException, GitAPIException {
+    GitMergeCommand command = createCommand();
+    MergeCommandRequest request = new MergeCommandRequest();
+    request.setTargetBranch("master");
+    request.setBranchToMerge("mergeable");
+    request.setAuthor(new Person("Dirk Gently", "dirk@holistic.det"));
+
+    MergeCommandResult mergeCommandResult = command.merge(request);
+
+    assertThat(mergeCommandResult.isSuccess()).isTrue();
+
+    Repository repository = createContext().open();
+    ObjectId firstMergeCommit = new Git(repository).log().add(repository.resolve("master")).setMaxCount(1).call().iterator().next().getId();
+
+    MergeCommandResult secondMergeCommandResult = command.merge(request);
+
+    assertThat(secondMergeCommandResult.isSuccess()).isTrue();
+
+    ObjectId secondMergeCommit = new Git(repository).log().add(repository.resolve("master")).setMaxCount(1).call().iterator().next().getId();
+
+    assertThat(secondMergeCommit).isEqualTo(firstMergeCommit);
+  }
+
   @Test
   public void shouldUseConfiguredCommitMessageTemplate() throws IOException, GitAPIException {
     GitMergeCommand command = createCommand();

From ea354690081850bbe1887effee606440c396200a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9=20Pfeuffer?= <rene.pfeuffer@cloudogu.com>
Date: Wed, 5 Dec 2018 16:46:31 +0100
Subject: [PATCH 05/20] Add merge links to repository resource

---
 .../scm/api/v2/resources/MergeResource.java   |  1 +
 .../RepositoryToRepositoryDtoMapper.java      |  4 ++++
 .../scm/api/v2/resources/ResourceLinks.java   | 19 +++++++++++++++++++
 3 files changed, 24 insertions(+)

diff --git a/scm-webapp/src/main/java/sonia/scm/api/v2/resources/MergeResource.java b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/MergeResource.java
index 5af32cedad..5c484b3ce9 100644
--- a/scm-webapp/src/main/java/sonia/scm/api/v2/resources/MergeResource.java
+++ b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/MergeResource.java
@@ -32,6 +32,7 @@ public class MergeResource {
   }
 
   @POST
+  @Path("")
   @Produces(VndMediaType.MERGE_RESULT)
   @Consumes(VndMediaType.MERGE_COMMAND)
   public Response merge(@PathParam("namespace") String namespace, @PathParam("name") String name, @Valid MergeCommandDto mergeCommand) {
diff --git a/scm-webapp/src/main/java/sonia/scm/api/v2/resources/RepositoryToRepositoryDtoMapper.java b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/RepositoryToRepositoryDtoMapper.java
index 29a4107aad..fa1522bc37 100644
--- a/scm-webapp/src/main/java/sonia/scm/api/v2/resources/RepositoryToRepositoryDtoMapper.java
+++ b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/RepositoryToRepositoryDtoMapper.java
@@ -55,6 +55,10 @@ public abstract class RepositoryToRepositoryDtoMapper extends BaseMapper<Reposit
       if (repositoryService.isSupported(Command.BRANCHES)) {
         linksBuilder.single(link("branches", resourceLinks.branchCollection().self(target.getNamespace(), target.getName())));
       }
+      if (repositoryService.isSupported(Command.MERGE)) {
+        linksBuilder.single(link("merge", resourceLinks.merge().merge(target.getNamespace(), target.getName())));
+        linksBuilder.single(link("mergeDryRun", resourceLinks.merge().dryRun(target.getNamespace(), target.getName())));
+      }
     }
     linksBuilder.single(link("changesets", resourceLinks.changeset().all(target.getNamespace(), target.getName())));
     linksBuilder.single(link("sources", resourceLinks.source().selfWithoutRevision(target.getNamespace(), target.getName())));
diff --git a/scm-webapp/src/main/java/sonia/scm/api/v2/resources/ResourceLinks.java b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/ResourceLinks.java
index 970166257a..38abb14d27 100644
--- a/scm-webapp/src/main/java/sonia/scm/api/v2/resources/ResourceLinks.java
+++ b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/ResourceLinks.java
@@ -541,4 +541,23 @@ class ResourceLinks {
     }
   }
 
+  public MergeLinks merge() {
+    return new MergeLinks(scmPathInfoStore.get());
+  }
+
+  static class MergeLinks {
+    private final LinkBuilder mergeLinkBuilder;
+
+    MergeLinks(ScmPathInfo pathInfo) {
+      this.mergeLinkBuilder = new LinkBuilder(pathInfo, RepositoryRootResource.class, RepositoryResource.class, MergeResource.class);
+    }
+
+    String merge(String namespace, String name) {
+      return mergeLinkBuilder.method("getRepositoryResource").parameters(namespace, name).method("merge").parameters().method("merge").parameters().href();
+    }
+
+    String dryRun(String namespace, String name) {
+      return mergeLinkBuilder.method("getRepositoryResource").parameters(namespace, name).method("merge").parameters().method("dryRun").parameters().href();
+    }
+  }
 }

From 244586e121e591e70bc08681cc0d8c6696ffac2c Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9=20Pfeuffer?= <rene.pfeuffer@cloudogu.com>
Date: Wed, 5 Dec 2018 17:03:02 +0100
Subject: [PATCH 06/20] Add documentation

---
 .../sonia/scm/api/v2/resources/MergeResource.java | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/scm-webapp/src/main/java/sonia/scm/api/v2/resources/MergeResource.java b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/MergeResource.java
index 5c484b3ce9..63fa2274ec 100644
--- a/scm-webapp/src/main/java/sonia/scm/api/v2/resources/MergeResource.java
+++ b/scm-webapp/src/main/java/sonia/scm/api/v2/resources/MergeResource.java
@@ -1,5 +1,7 @@
 package sonia.scm.api.v2.resources;
 
+import com.webcohesion.enunciate.metadata.rs.ResponseCode;
+import com.webcohesion.enunciate.metadata.rs.StatusCodes;
 import lombok.extern.slf4j.Slf4j;
 import org.apache.http.HttpStatus;
 import sonia.scm.repository.NamespaceAndName;
@@ -35,6 +37,13 @@ public class MergeResource {
   @Path("")
   @Produces(VndMediaType.MERGE_RESULT)
   @Consumes(VndMediaType.MERGE_COMMAND)
+  @StatusCodes({
+    @ResponseCode(code = 204, condition = "merge has been executed successfully"),
+    @ResponseCode(code = 401, condition = "not authenticated / invalid credentials"),
+    @ResponseCode(code = 403, condition = "not authorized, the current user does not have the privilege to write the repository"),
+    @ResponseCode(code = 409, condition = "The branches could not be merged automatically due to conflicts (conflicting files will be returned)"),
+    @ResponseCode(code = 500, condition = "internal server error")
+  })
   public Response merge(@PathParam("namespace") String namespace, @PathParam("name") String name, @Valid MergeCommandDto mergeCommand) {
     NamespaceAndName namespaceAndName = new NamespaceAndName(namespace, name);
     log.info("Merge in Repository {}/{} from {} to {}", namespace, name, mergeCommand.getSourceRevision(), mergeCommand.getTargetRevision());
@@ -50,6 +59,12 @@ public class MergeResource {
 
   @POST
   @Path("dry-run/")
+  @StatusCodes({
+    @ResponseCode(code = 204, condition = "merge can be done automatically"),
+    @ResponseCode(code = 401, condition = "not authenticated / invalid credentials"),
+    @ResponseCode(code = 409, condition = "The branches can not be merged automatically due to conflicts"),
+    @ResponseCode(code = 500, condition = "internal server error")
+  })
   public Response dryRun(@PathParam("namespace") String namespace, @PathParam("name") String name, @Valid MergeCommandDto mergeCommand) {
     NamespaceAndName namespaceAndName = new NamespaceAndName(namespace, name);
     log.info("Merge in Repository {}/{} from {} to {}", namespace, name, mergeCommand.getSourceRevision(), mergeCommand.getTargetRevision());

From 641022ba0193ee6b6b62d9055f15be26b700c4e7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9=20Pfeuffer?= <rene.pfeuffer@cloudogu.com>
Date: Wed, 5 Dec 2018 17:05:58 +0100
Subject: [PATCH 07/20] Fix unit test

---
 .../test/java/sonia/scm/api/v2/resources/ResourceLinksMock.java  | 1 +
 1 file changed, 1 insertion(+)

diff --git a/scm-webapp/src/test/java/sonia/scm/api/v2/resources/ResourceLinksMock.java b/scm-webapp/src/test/java/sonia/scm/api/v2/resources/ResourceLinksMock.java
index c2dc685306..0343888d6a 100644
--- a/scm-webapp/src/test/java/sonia/scm/api/v2/resources/ResourceLinksMock.java
+++ b/scm-webapp/src/test/java/sonia/scm/api/v2/resources/ResourceLinksMock.java
@@ -37,6 +37,7 @@ public class ResourceLinksMock {
     when(resourceLinks.uiPlugin()).thenReturn(new ResourceLinks.UIPluginLinks(uriInfo));
     when(resourceLinks.authentication()).thenReturn(new ResourceLinks.AuthenticationLinks(uriInfo));
     when(resourceLinks.index()).thenReturn(new ResourceLinks.IndexLinks(uriInfo));
+    when(resourceLinks.merge()).thenReturn(new ResourceLinks.MergeLinks(uriInfo));
 
     return resourceLinks;
   }

From d889cf083149985d74980e339d180bdc26e7d242 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9=20Pfeuffer?= <rene.pfeuffer@cloudogu.com>
Date: Wed, 5 Dec 2018 17:25:10 +0100
Subject: [PATCH 08/20] Fix permission check

---
 .../src/main/java/sonia/scm/repository/spi/GitMergeCommand.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java b/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java
index 888fef5b65..dc499df644 100644
--- a/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java
+++ b/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java
@@ -41,7 +41,7 @@ public class GitMergeCommand extends AbstractGitCommand implements MergeCommand
 
   @Override
   public MergeCommandResult merge(MergeCommandRequest request) {
-    RepositoryPermissions.permissionWrite(context.getRepository().getId()).check();
+    RepositoryPermissions.push(context.getRepository().getId()).check();
 
     try (WorkingCopy workingCopy = workdirFactory.createWorkingCopy(context)) {
       Repository repository = workingCopy.get();

From 540a525bc36c9358e3dcd7e0293a1a67d703a708 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9=20Pfeuffer?= <rene.pfeuffer@cloudogu.com>
Date: Fri, 7 Dec 2018 08:19:14 +0100
Subject: [PATCH 09/20] Use SCM protocol for internal merge command

---
 .../jgit/transport/ScmTransportProtocol.java  |  4 ++--
 .../spi/SimpleGitWorkdirFactory.java          |  7 +++++-
 .../repository/spi/GitMergeCommandTest.java   | 23 +++++++++++++++++++
 .../spi/SimpleGitWorkdirFactoryTest.java      | 17 ++++++++++++++
 4 files changed, 48 insertions(+), 3 deletions(-)

diff --git a/scm-plugins/scm-git-plugin/src/main/java/org/eclipse/jgit/transport/ScmTransportProtocol.java b/scm-plugins/scm-git-plugin/src/main/java/org/eclipse/jgit/transport/ScmTransportProtocol.java
index 3481ccd0d1..fc31f2d686 100644
--- a/scm-plugins/scm-git-plugin/src/main/java/org/eclipse/jgit/transport/ScmTransportProtocol.java
+++ b/scm-plugins/scm-git-plugin/src/main/java/org/eclipse/jgit/transport/ScmTransportProtocol.java
@@ -64,10 +64,10 @@ public class ScmTransportProtocol extends TransportProtocol
 {
 
   /** Field description */
-  private static final String NAME = "scm";
+  public static final String NAME = "scm";
 
   /** Field description */
-  private static final Set<String> SCHEMES = ImmutableSet.of("scm");
+  private static final Set<String> SCHEMES = ImmutableSet.of(NAME);
 
   //~--- constructors ---------------------------------------------------------
 
diff --git a/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/SimpleGitWorkdirFactory.java b/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/SimpleGitWorkdirFactory.java
index 22fce5f330..f12818aa80 100644
--- a/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/SimpleGitWorkdirFactory.java
+++ b/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/SimpleGitWorkdirFactory.java
@@ -3,6 +3,7 @@ package sonia.scm.repository.spi;
 import org.eclipse.jgit.api.Git;
 import org.eclipse.jgit.api.errors.GitAPIException;
 import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.transport.ScmTransportProtocol;
 import org.eclipse.jgit.util.FileUtils;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -45,12 +46,16 @@ public class SimpleGitWorkdirFactory implements GitWorkdirFactory {
 
   protected Repository cloneRepository(File bareRepository, File target) throws GitAPIException {
     return Git.cloneRepository()
-      .setURI(bareRepository.getAbsolutePath())
+      .setURI(createScmTransportProtocolUri(bareRepository))
       .setDirectory(target)
       .call()
       .getRepository();
   }
 
+  private String createScmTransportProtocolUri(File bareRepository) {
+    return ScmTransportProtocol.NAME + "://" + bareRepository.getAbsolutePath();
+  }
+
   private void close(Repository repository) {
     repository.close();
     try {
diff --git a/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitMergeCommandTest.java b/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitMergeCommandTest.java
index 380619dfa5..d0c7db6657 100644
--- a/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitMergeCommandTest.java
+++ b/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitMergeCommandTest.java
@@ -10,15 +10,26 @@ import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.PersonIdent;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.transport.ScmTransportProtocol;
+import org.eclipse.jgit.transport.Transport;
+import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
+import sonia.scm.repository.GitRepositoryHandler;
 import sonia.scm.repository.Person;
+import sonia.scm.repository.PreProcessorUtil;
+import sonia.scm.repository.RepositoryManager;
+import sonia.scm.repository.api.HookContextFactory;
 import sonia.scm.repository.api.MergeCommandResult;
 import sonia.scm.user.User;
 
 import java.io.IOException;
 
+import static com.google.inject.util.Providers.of;
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
 
 @SubjectAware(configuration = "classpath:sonia/scm/configuration/shiro.ini", username = "admin", password = "secret")
 public class GitMergeCommandTest extends AbstractGitCommandTestBase {
@@ -28,6 +39,18 @@ public class GitMergeCommandTest extends AbstractGitCommandTestBase {
   @Rule
   public ShiroRule shiro = new ShiroRule();
 
+  @Before
+  public void bindScmProtocol() {
+    HookContextFactory hookContextFactory = new HookContextFactory(mock(PreProcessorUtil.class));
+    RepositoryManager repositoryManager = mock(RepositoryManager.class);
+    HookEventFacade hookEventFacade = new HookEventFacade(of(repositoryManager), hookContextFactory);
+    GitRepositoryHandler gitRepositoryHandler = mock(GitRepositoryHandler.class);
+    Transport.register(new ScmTransportProtocol(of(hookEventFacade), of(gitRepositoryHandler)));
+
+    when(gitRepositoryHandler.getRepositoryId(any())).thenReturn("1");
+    when(repositoryManager.get("1")).thenReturn(new sonia.scm.repository.Repository());
+  }
+
   @Test
   public void shouldDetectMergeableBranches() {
     GitMergeCommand command = createCommand();
diff --git a/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/SimpleGitWorkdirFactoryTest.java b/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/SimpleGitWorkdirFactoryTest.java
index 0c39a1deb0..da26ebaf20 100644
--- a/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/SimpleGitWorkdirFactoryTest.java
+++ b/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/SimpleGitWorkdirFactoryTest.java
@@ -2,14 +2,23 @@ package sonia.scm.repository.spi;
 
 import org.eclipse.jgit.api.errors.GitAPIException;
 import org.eclipse.jgit.lib.Repository;
+import org.eclipse.jgit.transport.ScmTransportProtocol;
+import org.eclipse.jgit.transport.Transport;
+import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.TemporaryFolder;
+import sonia.scm.repository.GitRepositoryHandler;
+import sonia.scm.repository.PreProcessorUtil;
+import sonia.scm.repository.RepositoryManager;
+import sonia.scm.repository.api.HookContextFactory;
 
 import java.io.File;
 import java.io.IOException;
 
+import static com.google.inject.util.Providers.of;
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.spy;
 import static org.mockito.Mockito.verify;
 
@@ -18,6 +27,14 @@ public class SimpleGitWorkdirFactoryTest extends AbstractGitCommandTestBase {
   @Rule
   public TemporaryFolder temporaryFolder = new TemporaryFolder();
 
+  @Before
+  public void bindScmProtocol() {
+    HookContextFactory hookContextFactory = new HookContextFactory(mock(PreProcessorUtil.class));
+    HookEventFacade hookEventFacade = new HookEventFacade(of(mock(RepositoryManager.class)), hookContextFactory);
+    GitRepositoryHandler gitRepositoryHandler = mock(GitRepositoryHandler.class);
+    Transport.register(new ScmTransportProtocol(of(hookEventFacade), of(gitRepositoryHandler)));
+  }
+
   @Test
   public void emptyPoolShouldCreateNewWorkdir() throws IOException {
     SimpleGitWorkdirFactory factory = new SimpleGitWorkdirFactory(temporaryFolder.newFolder());

From 261e41f8bfa5d1b6678511342af111cb2a84cb90 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9=20Pfeuffer?= <rene.pfeuffer@cloudogu.com>
Date: Fri, 7 Dec 2018 08:49:37 +0100
Subject: [PATCH 10/20] Handle not existing revisions in merge

---
 .../sonia/scm/repository/spi/GitMergeCommand.java   | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java b/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java
index dc499df644..172c16dd17 100644
--- a/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java
+++ b/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java
@@ -6,6 +6,7 @@ import org.apache.shiro.subject.Subject;
 import org.eclipse.jgit.api.Git;
 import org.eclipse.jgit.api.MergeResult;
 import org.eclipse.jgit.api.errors.GitAPIException;
+import org.eclipse.jgit.api.errors.RefNotFoundException;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.merge.MergeStrategy;
@@ -23,6 +24,9 @@ import sonia.scm.user.User;
 import java.io.IOException;
 import java.text.MessageFormat;
 
+import static sonia.scm.ContextEntry.ContextBuilder.entity;
+import static sonia.scm.NotFoundException.notFound;
+
 public class GitMergeCommand extends AbstractGitCommand implements MergeCommand {
 
   private static final Logger logger = LoggerFactory.getLogger(GitMergeCommand.class);
@@ -94,6 +98,9 @@ public class GitMergeCommand extends AbstractGitCommand implements MergeCommand
     private void checkOutTargetBranch() {
       try {
         clone.checkout().setName(target).call();
+      } catch (RefNotFoundException e) {
+        logger.debug("could not checkout target branch {} for merge", target, e);
+        throw notFound(entity("revision", target).in(context.getRepository()));
       } catch (GitAPIException e) {
         throw new InternalRepositoryException(context.getRepository(), "could not checkout target branch for merge: " + target, e);
       }
@@ -102,9 +109,13 @@ public class GitMergeCommand extends AbstractGitCommand implements MergeCommand
     private MergeResult doMergeInClone() throws IOException {
       MergeResult result;
       try {
+        ObjectId sourceRevision = resolveRevision(toMerge);
+        if (sourceRevision == null) {
+          throw notFound(entity("revision", toMerge).in(context.getRepository()));
+        }
         result = clone.merge()
           .setCommit(false) // we want to set the author manually
-          .include(toMerge, resolveRevision(toMerge))
+          .include(toMerge, sourceRevision)
           .call();
       } catch (GitAPIException e) {
         throw new InternalRepositoryException(context.getRepository(), "could not merge branch " + toMerge + " into " + target, e);

From 830c155b3dc8f0224faca4bf3b060bf2115087d7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9=20Pfeuffer?= <rene.pfeuffer@cloudogu.com>
Date: Fri, 7 Dec 2018 10:10:50 +0100
Subject: [PATCH 11/20] Fix transport protocol

---
 .../java/org/eclipse/jgit/transport/ScmTransportProtocol.java  | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/scm-plugins/scm-git-plugin/src/main/java/org/eclipse/jgit/transport/ScmTransportProtocol.java b/scm-plugins/scm-git-plugin/src/main/java/org/eclipse/jgit/transport/ScmTransportProtocol.java
index fc31f2d686..8e1a6e5ef3 100644
--- a/scm-plugins/scm-git-plugin/src/main/java/org/eclipse/jgit/transport/ScmTransportProtocol.java
+++ b/scm-plugins/scm-git-plugin/src/main/java/org/eclipse/jgit/transport/ScmTransportProtocol.java
@@ -48,6 +48,7 @@ import org.eclipse.jgit.lib.RepositoryCache;
 
 import sonia.scm.repository.GitRepositoryHandler;
 import sonia.scm.repository.spi.HookEventFacade;
+import sonia.scm.web.CollectingPackParserListener;
 import sonia.scm.web.GitReceiveHook;
 
 //~--- JDK imports ------------------------------------------------------------
@@ -234,6 +235,8 @@ public class ScmTransportProtocol extends TransportProtocol
 
         pack.setPreReceiveHook(hook);
         pack.setPostReceiveHook(hook);
+
+        CollectingPackParserListener.set(pack);
       }
 
       return pack;

From 8b97e00b36628dd38469a2f558c94fc0580c26c6 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9=20Pfeuffer?= <rene.pfeuffer@cloudogu.com>
Date: Fri, 7 Dec 2018 13:28:21 +0100
Subject: [PATCH 12/20] Fix unit test

---
 .../sonia/scm/repository/spi/GitMergeCommandTest.java     | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitMergeCommandTest.java b/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitMergeCommandTest.java
index d0c7db6657..e36d50aa43 100644
--- a/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitMergeCommandTest.java
+++ b/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitMergeCommandTest.java
@@ -38,13 +38,15 @@ public class GitMergeCommandTest extends AbstractGitCommandTestBase {
 
   @Rule
   public ShiroRule shiro = new ShiroRule();
+  private GitRepositoryHandler gitRepositoryHandler;
+  private HookEventFacade hookEventFacade;
 
   @Before
   public void bindScmProtocol() {
     HookContextFactory hookContextFactory = new HookContextFactory(mock(PreProcessorUtil.class));
     RepositoryManager repositoryManager = mock(RepositoryManager.class);
-    HookEventFacade hookEventFacade = new HookEventFacade(of(repositoryManager), hookContextFactory);
-    GitRepositoryHandler gitRepositoryHandler = mock(GitRepositoryHandler.class);
+    hookEventFacade = new HookEventFacade(of(repositoryManager), hookContextFactory);
+    gitRepositoryHandler = mock(GitRepositoryHandler.class);
     Transport.register(new ScmTransportProtocol(of(hookEventFacade), of(gitRepositoryHandler)));
 
     when(gitRepositoryHandler.getRepositoryId(any())).thenReturn("1");
@@ -116,6 +118,8 @@ public class GitMergeCommandTest extends AbstractGitCommandTestBase {
     Repository repository = createContext().open();
     ObjectId firstMergeCommit = new Git(repository).log().add(repository.resolve("master")).setMaxCount(1).call().iterator().next().getId();
 
+    Transport.register(new ScmTransportProtocol(of(hookEventFacade), of(gitRepositoryHandler)));
+
     MergeCommandResult secondMergeCommandResult = command.merge(request);
 
     assertThat(secondMergeCommandResult.isSuccess()).isTrue();

From 438339ae495e135d7af684906f904dce70e827dc Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9=20Pfeuffer?= <rene.pfeuffer@cloudogu.com>
Date: Fri, 7 Dec 2018 13:33:58 +0100
Subject: [PATCH 13/20] Unbind scm protocol after test

---
 .../repository/spi/GitMergeCommandTest.java   | 20 +++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitMergeCommandTest.java b/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitMergeCommandTest.java
index e36d50aa43..88942e455f 100644
--- a/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitMergeCommandTest.java
+++ b/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitMergeCommandTest.java
@@ -12,6 +12,7 @@ import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.revwalk.RevCommit;
 import org.eclipse.jgit.transport.ScmTransportProtocol;
 import org.eclipse.jgit.transport.Transport;
+import org.junit.After;
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
@@ -38,21 +39,28 @@ public class GitMergeCommandTest extends AbstractGitCommandTestBase {
 
   @Rule
   public ShiroRule shiro = new ShiroRule();
-  private GitRepositoryHandler gitRepositoryHandler;
-  private HookEventFacade hookEventFacade;
+
+  private ScmTransportProtocol scmTransportProtocol;
 
   @Before
   public void bindScmProtocol() {
     HookContextFactory hookContextFactory = new HookContextFactory(mock(PreProcessorUtil.class));
     RepositoryManager repositoryManager = mock(RepositoryManager.class);
-    hookEventFacade = new HookEventFacade(of(repositoryManager), hookContextFactory);
-    gitRepositoryHandler = mock(GitRepositoryHandler.class);
-    Transport.register(new ScmTransportProtocol(of(hookEventFacade), of(gitRepositoryHandler)));
+    HookEventFacade hookEventFacade = new HookEventFacade(of(repositoryManager), hookContextFactory);
+    GitRepositoryHandler gitRepositoryHandler = mock(GitRepositoryHandler.class);
+    scmTransportProtocol = new ScmTransportProtocol(of(hookEventFacade), of(gitRepositoryHandler));
+
+    Transport.register(scmTransportProtocol);
 
     when(gitRepositoryHandler.getRepositoryId(any())).thenReturn("1");
     when(repositoryManager.get("1")).thenReturn(new sonia.scm.repository.Repository());
   }
 
+  @After
+  public void unregisterScmProtocol() {
+    Transport.unregister(scmTransportProtocol);
+  }
+
   @Test
   public void shouldDetectMergeableBranches() {
     GitMergeCommand command = createCommand();
@@ -118,7 +126,7 @@ public class GitMergeCommandTest extends AbstractGitCommandTestBase {
     Repository repository = createContext().open();
     ObjectId firstMergeCommit = new Git(repository).log().add(repository.resolve("master")).setMaxCount(1).call().iterator().next().getId();
 
-    Transport.register(new ScmTransportProtocol(of(hookEventFacade), of(gitRepositoryHandler)));
+//    Transport.register(new ScmTransportProtocol(of(hookEventFacade), of(gitRepositoryHandler)));
 
     MergeCommandResult secondMergeCommandResult = command.merge(request);
 

From 6193c1edda69b1c2adf40fff66b955f13074acc2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Maren=20S=C3=BCwer?= <maren.suewer@cloudogu.com>
Date: Fri, 7 Dec 2018 14:26:06 +0100
Subject: [PATCH 14/20] update apiclient for 409 errors

---
 .../packages/ui-components/src/apiclient.js     | 17 ++++++++++-------
 .../packages/ui-components/src/index.js         |  2 +-
 2 files changed, 11 insertions(+), 8 deletions(-)

diff --git a/scm-ui-components/packages/ui-components/src/apiclient.js b/scm-ui-components/packages/ui-components/src/apiclient.js
index 3fd90a2d7a..0cabb9429e 100644
--- a/scm-ui-components/packages/ui-components/src/apiclient.js
+++ b/scm-ui-components/packages/ui-components/src/apiclient.js
@@ -1,8 +1,9 @@
 // @flow
 import {contextPath} from "./urls";
 
-export const NOT_FOUND_ERROR_MESSAGE = "not found";
-export const UNAUTHORIZED_ERROR_MESSAGE = "unauthorized";
+export const NOT_FOUND_ERROR = new Error("not found");
+export const UNAUTHORIZED_ERROR = new Error("unauthorized");
+export const CONFLICT_ERROR = new Error("conflict");
 
 const fetchOptions: RequestOptions = {
   credentials: "same-origin",
@@ -15,24 +16,26 @@ function handleStatusCode(response: Response) {
   if (!response.ok) {
     switch (response.status) {
       case 401:
-        return throwErrorWithMessage(response, UNAUTHORIZED_ERROR_MESSAGE);
+        return throwErrorWithMessage(response, UNAUTHORIZED_ERROR);
       case 404:
-        return throwErrorWithMessage(response, NOT_FOUND_ERROR_MESSAGE);
+        return throwErrorWithMessage(response, NOT_FOUND_ERROR);
+      case 409:
+        return throwErrorWithMessage(response, CONFLICT_ERROR);
       default:
-        return throwErrorWithMessage(response, "server returned status code " + response.status);
+        return throwErrorWithMessage(response, new Error("server returned status code " + response.status));
     }
 
   }
   return response;
 }
 
-function throwErrorWithMessage(response: Response, message: string) {
+function throwErrorWithMessage(response: Response, err: Error) {
   return response.json().then(
     json => {
       throw Error(json.message);
     },
     () => {
-      throw Error(message);
+      throw err;
     }
   );
 }
diff --git a/scm-ui-components/packages/ui-components/src/index.js b/scm-ui-components/packages/ui-components/src/index.js
index 334e0a696c..b064a36145 100644
--- a/scm-ui-components/packages/ui-components/src/index.js
+++ b/scm-ui-components/packages/ui-components/src/index.js
@@ -25,7 +25,7 @@ export { default as Tooltip } from "./Tooltip";
 export { getPageFromMatch } from "./urls";
 export { default as Autocomplete} from "./Autocomplete";
 
-export { apiClient, NOT_FOUND_ERROR_MESSAGE, UNAUTHORIZED_ERROR_MESSAGE } from "./apiclient.js";
+export { apiClient, NOT_FOUND_ERROR, UNAUTHORIZED_ERROR, CONFLICT_ERROR } from "./apiclient.js";
 
 export * from "./buttons";
 export * from "./config";

From cc11f56bfa57066da1730306a580070e712fa80b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Maren=20S=C3=BCwer?= <maren.suewer@cloudogu.com>
Date: Mon, 10 Dec 2018 08:11:09 +0100
Subject: [PATCH 15/20] use new created error to fix test

---
 scm-ui/src/modules/auth.js | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/scm-ui/src/modules/auth.js b/scm-ui/src/modules/auth.js
index 489f701a74..e9bccb8fbc 100644
--- a/scm-ui/src/modules/auth.js
+++ b/scm-ui/src/modules/auth.js
@@ -2,10 +2,7 @@
 import type { Me } from "@scm-manager/ui-types";
 import * as types from "./types";
 
-import {
-  apiClient,
-  UNAUTHORIZED_ERROR_MESSAGE
-} from "@scm-manager/ui-components";
+import { apiClient, UNAUTHORIZED_ERROR } from "@scm-manager/ui-components";
 import { isPending } from "./pending";
 import { getFailure } from "./failure";
 import {
@@ -190,7 +187,7 @@ export const fetchMe = (link: string) => {
         dispatch(fetchMeSuccess(me));
       })
       .catch((error: Error) => {
-        if (error.message === UNAUTHORIZED_ERROR_MESSAGE) {
+        if (error === UNAUTHORIZED_ERROR) {
           dispatch(fetchMeUnauthenticated());
         } else {
           dispatch(fetchMeFailure(error));

From 040035e0843d1aa134095ae1c69afd44c54350e4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Maren=20S=C3=BCwer?= <maren.suewer@cloudogu.com>
Date: Mon, 10 Dec 2018 08:42:29 +0100
Subject: [PATCH 16/20] renaming

---
 .../packages/ui-components/src/apiclient.js            | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/scm-ui-components/packages/ui-components/src/apiclient.js b/scm-ui-components/packages/ui-components/src/apiclient.js
index 0cabb9429e..8c4bde6a72 100644
--- a/scm-ui-components/packages/ui-components/src/apiclient.js
+++ b/scm-ui-components/packages/ui-components/src/apiclient.js
@@ -16,20 +16,20 @@ function handleStatusCode(response: Response) {
   if (!response.ok) {
     switch (response.status) {
       case 401:
-        return throwErrorWithMessage(response, UNAUTHORIZED_ERROR);
+        return throwError(response, UNAUTHORIZED_ERROR);
       case 404:
-        return throwErrorWithMessage(response, NOT_FOUND_ERROR);
+        return throwError(response, NOT_FOUND_ERROR);
       case 409:
-        return throwErrorWithMessage(response, CONFLICT_ERROR);
+        return throwError(response, CONFLICT_ERROR);
       default:
-        return throwErrorWithMessage(response, new Error("server returned status code " + response.status));
+        return throwError(response, new Error("server returned status code " + response.status));
     }
 
   }
   return response;
 }
 
-function throwErrorWithMessage(response: Response, err: Error) {
+function throwError(response: Response, err: Error) {
   return response.json().then(
     json => {
       throw Error(json.message);

From 8b518d320d8a703a94c559a139221b426ddd9c89 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9=20Pfeuffer?= <rene.pfeuffer@cloudogu.com>
Date: Mon, 10 Dec 2018 08:59:19 +0100
Subject: [PATCH 17/20] Fix checkout of target branch

---
 .../main/java/sonia/scm/repository/spi/GitMergeCommand.java  | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java b/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java
index 172c16dd17..1d0e8f768b 100644
--- a/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java
+++ b/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java
@@ -95,9 +95,10 @@ public class GitMergeCommand extends AbstractGitCommand implements MergeCommand
       }
     }
 
-    private void checkOutTargetBranch() {
+    private void checkOutTargetBranch() throws IOException {
       try {
-        clone.checkout().setName(target).call();
+        ObjectId targetRevision = resolveRevision(target);
+        clone.checkout().setName(targetRevision.getName()).call();
       } catch (RefNotFoundException e) {
         logger.debug("could not checkout target branch {} for merge", target, e);
         throw notFound(entity("revision", target).in(context.getRepository()));

From 0e333002dbf43db093d6187f3926950c144d340b Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9=20Pfeuffer?= <rene.pfeuffer@cloudogu.com>
Date: Mon, 10 Dec 2018 11:43:27 +0100
Subject: [PATCH 18/20] Create local branch for target during merge

---
 .../scm/repository/spi/GitMergeCommand.java   | 24 ++++++++++++----
 .../repository/spi/GitMergeCommandTest.java   | 28 +++++++++++++++++--
 2 files changed, 45 insertions(+), 7 deletions(-)

diff --git a/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java b/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java
index 1d0e8f768b..072fdff514 100644
--- a/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java
+++ b/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java
@@ -97,16 +97,30 @@ public class GitMergeCommand extends AbstractGitCommand implements MergeCommand
 
     private void checkOutTargetBranch() throws IOException {
       try {
-        ObjectId targetRevision = resolveRevision(target);
-        clone.checkout().setName(targetRevision.getName()).call();
+        clone.checkout().setName(target).call();
       } catch (RefNotFoundException e) {
-        logger.debug("could not checkout target branch {} for merge", target, e);
-        throw notFound(entity("revision", target).in(context.getRepository()));
+        logger.trace("could not checkout target branch {} for merge directly; trying to create local branch", target, e);
+        checkOutTargetAsNewLocalBranch();
       } catch (GitAPIException e) {
         throw new InternalRepositoryException(context.getRepository(), "could not checkout target branch for merge: " + target, e);
       }
     }
 
+    private void checkOutTargetAsNewLocalBranch() throws IOException {
+      try {
+        ObjectId targetRevision = resolveRevision(target);
+        if (targetRevision == null) {
+          throw notFound(entity("revision", target).in(context.getRepository()));
+        }
+        clone.checkout().setStartPoint(targetRevision.getName()).setName(target).setCreateBranch(true).call();
+      } catch (RefNotFoundException e) {
+        logger.debug("could not checkout target branch {} for merge as local branch", target, e);
+        throw notFound(entity("revision", target).in(context.getRepository()));
+      } catch (GitAPIException e) {
+        throw new InternalRepositoryException(context.getRepository(), "could not checkout target branch for merge as local branch: " + target, e);
+      }
+    }
+
     private MergeResult doMergeInClone() throws IOException {
       MergeResult result;
       try {
@@ -164,7 +178,7 @@ public class GitMergeCommand extends AbstractGitCommand implements MergeCommand
       try {
         clone.push().call();
       } catch (GitAPIException e) {
-        throw new InternalRepositoryException(context.getRepository(), "could not push merged branch " + toMerge + " to origin", e);
+        throw new InternalRepositoryException(context.getRepository(), "could not push merged branch " + target + " to origin", e);
       }
       logger.debug("pushed merged branch {}", target);
     }
diff --git a/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitMergeCommandTest.java b/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitMergeCommandTest.java
index 88942e455f..7e50b48b9a 100644
--- a/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitMergeCommandTest.java
+++ b/scm-plugins/scm-git-plugin/src/test/java/sonia/scm/repository/spi/GitMergeCommandTest.java
@@ -126,8 +126,6 @@ public class GitMergeCommandTest extends AbstractGitCommandTestBase {
     Repository repository = createContext().open();
     ObjectId firstMergeCommit = new Git(repository).log().add(repository.resolve("master")).setMaxCount(1).call().iterator().next().getId();
 
-//    Transport.register(new ScmTransportProtocol(of(hookEventFacade), of(gitRepositoryHandler)));
-
     MergeCommandResult secondMergeCommandResult = command.merge(request);
 
     assertThat(secondMergeCommandResult.isSuccess()).isTrue();
@@ -196,6 +194,32 @@ public class GitMergeCommandTest extends AbstractGitCommandTestBase {
     assertThat(mergeAuthor.getEmailAddress()).isEqualTo("dirk@holistic.det");
   }
 
+  @Test
+  public void shouldMergeIntoNotDefaultBranch() throws IOException, GitAPIException {
+    GitMergeCommand command = createCommand();
+    MergeCommandRequest request = new MergeCommandRequest();
+    request.setAuthor(new Person("Dirk Gently", "dirk@holistic.det"));
+    request.setTargetBranch("mergeable");
+    request.setBranchToMerge("master");
+
+    MergeCommandResult mergeCommandResult = command.merge(request);
+
+    Repository repository = createContext().open();
+    assertThat(mergeCommandResult.isSuccess()).isTrue();
+
+    Iterable<RevCommit> commits = new Git(repository).log().add(repository.resolve("mergeable")).setMaxCount(1).call();
+    RevCommit mergeCommit = commits.iterator().next();
+    PersonIdent mergeAuthor = mergeCommit.getAuthorIdent();
+    String message = mergeCommit.getFullMessage();
+    assertThat(mergeAuthor.getName()).isEqualTo("Dirk Gently");
+    assertThat(mergeAuthor.getEmailAddress()).isEqualTo("dirk@holistic.det");
+    assertThat(message).contains("master", "mergeable");
+    // We expect the merge result of file b.txt here by looking up the sha hash of its content.
+    // If the file is missing (aka not merged correctly) this will throw a MissingObjectException:
+    byte[] contentOfFileB = repository.open(repository.resolve("9513e9c76e73f3e562fd8e4c909d0607113c77c6")).getBytes();
+    assertThat(new String(contentOfFileB)).isEqualTo("b\ncontent from branch\n");
+  }
+
   private GitMergeCommand createCommand() {
     return new GitMergeCommand(createContext(), repository, new SimpleGitWorkdirFactory());
   }

From a54faf123311edcf162cfb9209787df8685c3ee1 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ren=C3=A9=20Pfeuffer?= <rene.pfeuffer@cloudogu.com>
Date: Mon, 10 Dec 2018 12:01:13 +0100
Subject: [PATCH 19/20] Do not merge with fast forward

---
 .../src/main/java/sonia/scm/repository/spi/GitMergeCommand.java | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java b/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java
index 072fdff514..be91d06361 100644
--- a/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java
+++ b/scm-plugins/scm-git-plugin/src/main/java/sonia/scm/repository/spi/GitMergeCommand.java
@@ -4,6 +4,7 @@ import com.google.common.base.Strings;
 import org.apache.shiro.SecurityUtils;
 import org.apache.shiro.subject.Subject;
 import org.eclipse.jgit.api.Git;
+import org.eclipse.jgit.api.MergeCommand.FastForwardMode;
 import org.eclipse.jgit.api.MergeResult;
 import org.eclipse.jgit.api.errors.GitAPIException;
 import org.eclipse.jgit.api.errors.RefNotFoundException;
@@ -129,6 +130,7 @@ public class GitMergeCommand extends AbstractGitCommand implements MergeCommand
           throw notFound(entity("revision", toMerge).in(context.getRepository()));
         }
         result = clone.merge()
+          .setFastForward(FastForwardMode.NO_FF)
           .setCommit(false) // we want to set the author manually
           .include(toMerge, sourceRevision)
           .call();

From 2a45f250ed3415d9033cf34e8709a5f4e539d7dd Mon Sep 17 00:00:00 2001
From: Sebastian Sdorra <sebastian.sdorra@cloudogu.com>
Date: Mon, 10 Dec 2018 12:20:12 +0000
Subject: [PATCH 20/20] Close branch feature/merge_endpoint