Support shallow clone/fetch

Uses the new property in grgit to allow shallow fetch.

Fixes #57

gradle.lockfile

@@ -4,8 +4,8 @@
 cglib:cglib-nodep:3.3.0=compatTestCompileClasspath,compatTestRuntimeClasspath
 com.googlecode.javaewah:JavaEWAH:1.1.13=compatTestCompileClasspath,compatTestRuntimeClasspath,compileClasspath,runtimeClasspath,testCompileClasspath,testRuntimeClasspath
 net.bytebuddy:byte-buddy:1.11.0=compatTestCompileClasspath,compatTestRuntimeClasspath
-org.ajoberstar.grgit:grgit-core:5.1.0=compatTestCompileClasspath,compatTestRuntimeClasspath,compileClasspath,runtimeClasspath,testCompileClasspath,testRuntimeClasspath
-org.ajoberstar.grgit:grgit-gradle:5.1.0=compileClasspath,runtimeClasspath,testCompileClasspath,testRuntimeClasspath
+org.ajoberstar.grgit:grgit-core:5.2.0=compatTestCompileClasspath,compatTestRuntimeClasspath,compileClasspath,runtimeClasspath,testCompileClasspath,testRuntimeClasspath
+org.ajoberstar.grgit:grgit-gradle:5.2.0=compileClasspath,runtimeClasspath,testCompileClasspath,testRuntimeClasspath
 org.apiguardian:apiguardian-api:1.1.0=compatTestCompileClasspath,compatTestRuntimeClasspath
 org.assertj:assertj-core:3.16.1=compatTestCompileClasspath,compatTestRuntimeClasspath
 org.codehaus.groovy:groovy:3.0.17=compatTestCompileClasspath,compatTestRuntimeClasspath,compileClasspath,runtimeClasspath,testCompileClasspath,testRuntimeClasspath

src/compatTest/groovy/org/ajoberstar/gradle/git/publish/BaseCompatTest.groovy

@@ -92,6 +92,41 @@ gitPublish {
     remoteFile('content.txt').text == 'published content here'
   }
 
+  def 'publish with fetchDepth 1 adds to history if branch already exists'() {
+    given:
+    remote.checkout(branch: 'gh-pages')
+    remoteFile('index.md') << 'And has great content'
+    remote.add(patterns: ['.'])
+    remote.commit(message: 'second pages commit')
+    remote.checkout(branch: 'master')
+
+    projectFile('src/content.txt') << 'published content here'
+
+    buildFile << """
+plugins {
+  id 'org.ajoberstar.git-publish'
+}
+
+gitPublish {
+  repoUri = '${remote.repository.rootDir.toURI()}'
+  branch = 'gh-pages'
+  fetchDepth = 1
+  contents.from 'src'
+}
+"""
+    when:
+    def result = build()
+    and:
+    remote.checkout(branch: 'gh-pages')
+    then:
+    result.task(':gitPublishPush').outcome == TaskOutcome.SUCCESS
+    remote.log().size() == 3
+    remoteFile('content.txt').text == 'published content here'
+    def working = Grgit.open(dir: "${projectDir}/build/gitPublish/main")
+    working.head().parentIds.collect { working.resolve.toCommit(it).parentIds == [] }
+    working.close()
+  }
+
   def 'reset pulls from reference repo if available before pulling from remote'() {
     given:
     def referenceDir = new File(tempDir, 'reference')
@@ -339,7 +374,6 @@ task hello {
     notThrown(UnexpectedBuildFailure)
   }
 
-  @IgnoreIf({ Integer.parseInt(System.properties['compat.gradle.version'].split('\\.')[0]) < 5 })
   def 'commit message can be changed'() {
      given:
     projectFile('src/content.txt') << 'published content here'

src/main/java/org/ajoberstar/gradle/git/publish/GitPublication.java

@@ -16,6 +16,7 @@ public class GitPublication implements Named {
   private final Property<String> repoUri;
   private final Property<String> referenceRepoUri;
   private final Property<String> branch;
+  private final Property<Integer> fetchDepth;
   private final Property<String> commitMessage;
   private final Property<Boolean> sign;
   private final CopySpec contents;
@@ -27,6 +28,7 @@ public GitPublication(String name, Project project, ObjectFactory objectFactory)
     this.repoUri = objectFactory.property(String.class);
     this.referenceRepoUri = objectFactory.property(String.class);
     this.branch = objectFactory.property(String.class);
+    this.fetchDepth = objectFactory.property(Integer.class);
     this.commitMessage = objectFactory.property(String.class);
     this.sign = objectFactory.property(Boolean.class);
 
@@ -56,6 +58,10 @@ public Property<String> getBranch() {
     return branch;
   }
 
+  public Property<Integer> getFetchDepth() {
+    return fetchDepth;
+  }
+
   public Property<String> getCommitMessage() {
     return commitMessage;
   }

src/main/java/org/ajoberstar/gradle/git/publish/GitPublishExtension.java

@@ -43,6 +43,10 @@ public Property<String> getBranch() {
     return publications.getByName("main").getBranch();
   }
 
+  public Property<Integer> getFetchDepth() {
+    return publications.getByName("main").getFetchDepth();
+  }
+
   public Property<String> getCommitMessage() {
     return publications.getByName("main").getCommitMessage();
   }

src/main/java/org/ajoberstar/gradle/git/publish/GitPublishPlugin.java

@@ -73,6 +73,7 @@ private TaskProvider<GitPublishReset> createResetTask(Project project, GitPublic
       task.getRepoUri().set(publication.getRepoUri());
       task.getReferenceRepoUri().set(publication.getReferenceRepoUri());
       task.getBranch().set(publication.getBranch());
+      task.getFetchDepth().set(publication.getFetchDepth());
       task.setPreserve(publication.getPreserve());
     });
   }

src/main/java/org/ajoberstar/gradle/git/publish/tasks/GitPublishReset.java

@@ -28,6 +28,7 @@ public class GitPublishReset extends DefaultTask {
   private final Property<String> repoUri;
   private final Property<String> referenceRepoUri;
   private final Property<String> branch;
+  private final Property<Integer> fetchDepth;
   private PatternFilterable preserve;
   private final ObjectFactory objectFactory;
 
@@ -37,6 +38,7 @@ public GitPublishReset(ObjectFactory objectFactory) {
     this.repoUri = objectFactory.property(String.class);
     this.referenceRepoUri = objectFactory.property(String.class);
     this.branch = objectFactory.property(String.class);
+    this.fetchDepth = objectFactory.property(Integer.class);
     this.objectFactory = objectFactory;
   }
 
@@ -60,6 +62,12 @@ public Property<String> getBranch() {
     return branch;
   }
 
+  @Input
+  @Optional
+  public Property<Integer> getFetchDepth() {
+    return fetchDepth;
+  }
+
   @Internal
   public PatternFilterable getPreserve() {
     return preserve;
@@ -118,6 +126,7 @@ public void reset() throws IOException {
         git.fetch(op -> {
           op.setRefSpecs(Arrays.asList(String.format("+refs/heads/%s:refs/remotes/reference/%s", pubBranch, pubBranch)));
           op.setTagMode("none");
+          op.setDepth(getFetchDepth().getOrNull());
         });
       }
     }
@@ -136,6 +145,7 @@ public void reset() throws IOException {
         getLogger().info("Fetching from remote repo: " + repoUri.get());
         op.setRefSpecs(Arrays.asList(String.format("+refs/heads/%s:refs/remotes/origin/%s", pubBranch, pubBranch)));
         op.setTagMode("none");
+        op.setDepth(getFetchDepth().getOrNull());
       });
 
       // make sure local branch exists