Compute trailers in changeset pre processing

Doing so, the trailers are available for other plugins inspecting
changesets, not only for the frontend.

scm-core/src/main/java/sonia/scm/repository/Changeset.java

@@ -31,6 +31,7 @@ import sonia.scm.util.Util;
 import sonia.scm.util.ValidationUtil;
 
 import java.util.ArrayList;
+import java.util.Collection;
 import java.util.Date;
 import java.util.List;
 
@@ -79,6 +80,11 @@ public class Changeset extends BasicPropertiesAware implements ModelObject {
    */
   private List<String> tags;
 
+  /**
+   * Trailers for this changeset like reviewers or co-authors
+   */
+  private Collection<Trailer> trailers;
+
   public Changeset() {}
 
   public Changeset(String id, Long date, Person author)
@@ -225,6 +231,10 @@ public class Changeset extends BasicPropertiesAware implements ModelObject {
     return tags;
   }
 
+  public Collection<Trailer> getTrailers() {
+    return trailers;
+  }
+
   /**
    * Returns true if the changeset is valid.
    *
@@ -300,4 +310,7 @@ public class Changeset extends BasicPropertiesAware implements ModelObject {
     this.tags = tags;
   }
 
+  public void setTrailers(Collection<Trailer> trailers) {
+    this.trailers = trailers;
+  }
 }

scm-core/src/main/java/sonia/scm/repository/ChangesetTrailerPreProcessorFactory.java

@@ -0,0 +1,61 @@
+/*
+ * 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;
+
+import sonia.scm.plugin.Extension;
+
+import javax.inject.Inject;
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+import java.util.Set;
+
+@Extension
+public class ChangesetTrailerPreProcessorFactory implements ChangesetPreProcessorFactory {
+
+  private final Set<ChangesetTrailerProvider> changesetTrailerProviderSet;
+
+  @Inject
+  public ChangesetTrailerPreProcessorFactory(Set<ChangesetTrailerProvider> changesetTrailerProviderSet) {
+    this.changesetTrailerProviderSet = changesetTrailerProviderSet;
+  }
+
+  @Override
+  public ChangesetPreProcessor createPreProcessor(Repository repository) {
+    return changeset -> {
+      Collection<Trailer> existingTrailers = changeset.getTrailers();
+      List<Trailer> collectedTrailers;
+      if (existingTrailers == null && existingTrailers.isEmpty()) {
+        collectedTrailers = new ArrayList<>();
+      } else {
+        collectedTrailers = new ArrayList<>(existingTrailers);
+      }
+      changesetTrailerProviderSet.stream()
+        .flatMap(changesetTrailers -> changesetTrailers.getTrailers(repository, changeset).stream())
+        .forEach(collectedTrailers::add);
+      changeset.setTrailers(collectedTrailers);
+    };
+  }
+}

scm-ui/ui-components/src/repos/changesets/ChangesetAuthor.tsx

@@ -53,7 +53,7 @@ class ChangesetAuthor extends React.Component<Props> {
   }
 
   getCoAuthorsFromChangeset() {
-    return this.props.changeset.trailerPersons.filter(p => p.trailerType === "Co-authored-by");
+    return this.props.changeset.trailers.filter(p => p.trailerType === "Co-authored-by").map(trailer => trailer.person);
   }
 
   renderCoAuthors() {

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

@@ -33,7 +33,6 @@ import org.mapstruct.MappingTarget;
 import org.mapstruct.ObjectFactory;
 import sonia.scm.repository.Branch;
 import sonia.scm.repository.Changeset;
-import sonia.scm.repository.ChangesetTrailerProvider;
 import sonia.scm.repository.Person;
 import sonia.scm.repository.Repository;
 import sonia.scm.repository.Tag;
@@ -44,10 +43,8 @@ import sonia.scm.repository.api.RepositoryServiceFactory;
 import sonia.scm.web.EdisonHalAppender;
 
 import javax.inject.Inject;
-import java.util.ArrayList;
 import java.util.List;
 import java.util.Scanner;
-import java.util.Set;
 import java.util.function.Function;
 import java.util.stream.Collectors;
 
@@ -73,23 +70,10 @@ public abstract class DefaultChangesetToChangesetDtoMapper extends HalAppenderMa
   @Inject
   private TagCollectionToDtoMapper tagCollectionToDtoMapper;
 
-  @Inject
-  private Set<ChangesetTrailerProvider> changesetTrailerProviderSet;
-
   abstract TrailerDto map(Trailer trailer);
 
   abstract PersonDto map(Person person);
 
-  @AfterMapping
-  void appendTrailerPersons(Changeset changeset, @MappingTarget ChangesetDto target, @Context Repository repository) {
-    List<TrailerDto> collectedTrailers = new ArrayList<>();
-    changesetTrailerProviderSet.stream()
-      .flatMap(changesetTrailers -> changesetTrailers.getTrailers(repository, changeset).stream())
-      .map(this::map)
-      .forEach(collectedTrailers::add);
-    target.setTrailers(collectedTrailers);
-  }
-
   @AfterMapping
   void removeTrailerFromChangesetDescription(@MappingTarget ChangesetDto target) {
     StringBuilder builder = new StringBuilder();