Added support for git describe when all tags are on different branches

- Before it throws exception on such situation
- Now it display commit d if set
- Added test repo + test
- In process cleaned up gitk.cache

Author: Karol Lassak

src/main/java/pl/project13/jgit/DescribeCommand.java

@@ -319,14 +319,15 @@ public DescribeResult call() throws GitAPIException {
       return new DescribeResult(tagName, dirty, dirtyOption);
     }
 
-    if (foundZeroTags(tagObjectIdToName)) {
+    // get commits, up until the nearest tag
+    List<RevCommit> commits = findCommitsUntilSomeTag(repo, headCommit, tagObjectIdToName);
+
+    // if there is no tags or any tag is not on that branch then return generic describe
+    if (foundZeroTags(tagObjectIdToName) || commits.isEmpty()) {
       return new DescribeResult(objectReader, headCommitId, dirty, dirtyOption)
           .withCommitIdAbbrev(abbrev);
     }
 
-    // get commits, up until the nearest tag
-    List<RevCommit> commits = findCommitsUntilSomeTag(repo, headCommit, tagObjectIdToName);
-
     // check how far away from a tag we are
 
     int distance = distanceBetween(repo, headCommit, commits.get(0));
@@ -425,7 +426,8 @@ private List<RevCommit> findCommitsUntilSomeTag(Repository repo, RevCommit head,
         }
       }
 
-      throw new RuntimeException("Did not find any commits until some tag");
+//      throw new RuntimeException("Did not find any commits until some tag");
+      return Collections.emptyList();
     } catch (Exception e) {
       throw new RuntimeException("Unable to find commits until some tag", e);
     }

src/test/java/pl/project13/jgit/DescribeCommandIntegrationTest.java

@@ -95,7 +95,31 @@ public void shouldGiveTheCommitIdWhenNothingElseCanBeFound() throws Exception {
     RevCommit HEAD = git().log().call().iterator().next();
     assertThat(res.toString()).isEqualTo(abbrev(HEAD.getName()));
   }
+  
+  @Test
+  public void shouldGiveTheCommitIdWhenTagIsOnOtherBranch() throws Exception {
+    // given
+    mavenSandbox
+        .withParentProject(PROJECT_NAME, "jar")
+        .withNoChildProject()
+        .withGitRepoInParent(AvailableGitTestRepo.WITH_TAG_ON_DIFFERENT_BRANCH)
+        .create(FileSystemMavenSandbox.CleanUp.CLEANUP_FIRST);
 
+    Repository repo = git().getRepository();
+
+    // when
+    DescribeCommand command = spy(DescribeCommand.on(repo));
+    doReturn(false).when(command).findDirtyState(any(Repository.class));
+
+    command.setVerbose(true);
+    DescribeResult res = command.call();
+
+    // then
+    assertThat(res).isNotNull();
+
+    RevCommit HEAD = git().log().call().iterator().next();
+    assertThat(res.toString()).isEqualTo(abbrev(HEAD.getName()));
+  }
 
   @Test
   public void shouldGiveTheCommitIdWhenNothingElseCanBeFoundAndUseAbbrevVersionOfIt() throws Exception {

src/test/java/pl/project13/maven/git/AvailableGitTestRepo.java

@@ -55,7 +55,8 @@ public enum AvailableGitTestRepo {
    * 9597545 - (annotated-tag) initial commit (6 minutes ago) <Konrad Malawski>
    * </pre>
    */
-  WITH_LIGHTWEIGHT_TAG_BEFORE_ANNOTATED_TAG("src/test/resources/_git_lightweight_tag_before_annotated_tag");
+  WITH_LIGHTWEIGHT_TAG_BEFORE_ANNOTATED_TAG("src/test/resources/_git_lightweight_tag_before_annotated_tag"),
+  WITH_TAG_ON_DIFFERENT_BRANCH("src/test/resources/_git_with_tag_on_different_branch");
 
   private String dir;
 

src/test/resources/_git_of_git_commit_id/gitk.cache

@@ -0,0 +1,16 @@
+Change in tag
+# Please enter the commit message for your changes. Lines starting
+# with '#' will be ignored, and an empty message aborts the commit.
+# On branch test
+# Changes to be committed:
+#   (use "git reset HEAD <file>..." to unstage)
+#
+#	modified:   readme.txt
+#
+diff --git a/readme.txt b/readme.txt
+index 53a90bf..e69336e 100644
+--- a/readme.txt
++++ b/readme.txt
+@@ -1 +1 @@
+-Empty
++Other content

src/test/resources/_git_with_commit_that_has_two_tags/gitk.cache

@@ -0,0 +1 @@
+ref: refs/heads/master

src/test/resources/_git_with_tag_on_different_branch/COMMIT_EDITMSG

@@ -0,0 +1,7 @@
+[core]
+	repositoryformatversion = 0
+	filemode = true
+	bare = false
+	logallrefupdates = true
+	ignorecase = true
+	precomposeunicode = false

src/test/resources/_git_with_tag_on_different_branch/HEAD

@@ -0,0 +1 @@
+Unnamed repository; edit this file 'description' to name the repository.

src/test/resources/_git_with_tag_on_different_branch/config

@@ -0,0 +1,15 @@
+#!/bin/sh
+#
+# An example hook script to check the commit log message taken by
+# applypatch from an e-mail message.
+#
+# The hook should exit with non-zero status after issuing an
+# appropriate message if it wants to stop the commit.  The hook is
+# allowed to edit the commit message file.
+#
+# To enable this hook, rename this file to "applypatch-msg".
+
+. git-sh-setup
+test -x "$GIT_DIR/hooks/commit-msg" &&
+	exec "$GIT_DIR/hooks/commit-msg" ${1+"$@"}
+: