Guess upstream-tag based on merge-base

In some unfortunate cases you might have something like this:

$ git tag
v1.0
vyatta/1.0-0something1

... where later tag is closer to describe current HEAD.

With upstream-tag set to v%(version)s find_tag() is going to propose
something based on vyatta/1.0-0something1 which is not expected.

The problem is that find_tag() returns tags, which match the
upstream-tag format, but which are not on the upstream-branch at all.

To fix this find_tag()/git-describe should not be used to determine
the closest upstream-tag.

Closes: gh#7

6 files changed, 80 insertions, 8 deletions

diff --git a/gbp/deb/git.py b/gbp/deb/git.py
index 87df84eb..28177eb3 100644
--- a/gbp/deb/git.py
+++ b/gbp/deb/git.py
@@ -63,7 +63,8 @@ class DebianGitRepository(GitRepository):
                     return None
         return None
 
-    def debian_version_from_upstream(self, upstream_tag_format, commit='HEAD',
+    def debian_version_from_upstream(self, upstream_tag_format,
+                                     upstream_branch, commit='HEAD',
                                      epoch=None):
         """
         Build the Debian version that a package based on upstream commit
@@ -71,13 +72,15 @@ class DebianGitRepository(GitRepository):
 
         @param upstream_tag_format: the tag format on the upstream branch
         @type upstream_tag_format: C{str}
+        @param upstream_branch: the upstream branch
+        @type upstream_branch: C{str}
         @param commit: the commit to search for the latest upstream version
         @param epoch: an epoch to use
         @returns: a new debian version
         @raises GitRepositoryError: if no upstream tag was found
         """
         pattern = upstream_tag_format % dict(version='*')
-        tag = self.find_tag(commit, pattern=pattern)
+        tag = self.find_branch_tag(commit, upstream_branch, pattern=pattern)
         version = self.tag_to_version(tag, upstream_tag_format)
 
         version += "-1"
diff --git a/gbp/git/repository.py b/gbp/git/repository.py
index 689430f0..3b208bf4 100644
--- a/gbp/git/repository.py
+++ b/gbp/git/repository.py
@@ -713,6 +713,21 @@ class GitRepository(object):
         """
         return self.describe(commit, pattern, abbrev=0)
 
+    def find_branch_tag(self, commit, branch, pattern=None):
+        """
+        Find the closest tag on a certain branch to a given commit
+
+        @param commit: the commit to describe
+        @type commit: C{str}
+        @type branch: C{str}
+        @param pattern: only look for tags matching I{pattern}
+        @type pattern: C{str}
+        @return: the found tag
+        @rtype: C{str}
+        """
+        base_commit = self.get_merge_base(commit, branch)
+        return self.describe(base_commit, pattern, abbrev=0)
+
     def get_tags(self, pattern=None):
         """
         List tags
diff --git a/gbp/scripts/dch.py b/gbp/scripts/dch.py
index d0e9794d..bc223f93 100644
--- a/gbp/scripts/dch.py
+++ b/gbp/scripts/dch.py
@@ -38,18 +38,19 @@ user_customizations = {}
 snapshot_re = re.compile("\s*\*\* SNAPSHOT build @(?P<commit>[a-z0-9]+)\s+\*\*")
 
 
-def guess_version_from_upstream(repo, upstream_tag_format, cp):
+def guess_version_from_upstream(repo, upstream_tag_format, upstream_branch, cp):
     """
     Guess the version based on the latest version on the upstream branch
     """
     try:
         version = repo.debian_version_from_upstream(upstream_tag_format,
+                                                    upstream_branch,
                                                     epoch=cp.epoch)
         gbp.log.debug("Found upstream version %s." % version)
         if compare_versions(version, cp.version) > 0:
             return version
-    except GitRepositoryError:
-        gbp.log.debug("No upstream tag found")
+    except GitRepositoryError as e:
+        gbp.log.debug("No upstream tag found: %s" % e)
     return None
 
 
@@ -318,6 +319,7 @@ def build_parser(name):
     parser.add_option_group(custom_group)
 
     parser.add_boolean_config_file_option(option_name = "ignore-branch", dest="ignore_branch")
+    naming_group.add_config_file_option(option_name="upstream-branch", dest="upstream_branch")
     naming_group.add_config_file_option(option_name="debian-branch", dest="debian_branch")
     naming_group.add_config_file_option(option_name="upstream-tag", dest="upstream_tag")
     naming_group.add_config_file_option(option_name="debian-tag", dest="debian_tag")
@@ -474,7 +476,8 @@ def main(argv):
 
         if add_section and not version_change and not source.is_native():
             # Get version from upstream if none provided
-            v = guess_version_from_upstream(repo, options.upstream_tag, cp)
+            v = guess_version_from_upstream(repo, options.upstream_tag,
+                                            options.upstream_branch, cp)
             if v:
                 version_change['version'] = v
 
diff --git a/tests/03_test_dch_guess_version.py b/tests/03_test_dch_guess_version.py
index 38d097c2..d7035018 100644
--- a/tests/03_test_dch_guess_version.py
+++ b/tests/03_test_dch_guess_version.py
@@ -15,14 +15,18 @@ class TestGuessVersionFromUpstream(testutils.DebianGitTestRepo):
         cp = testutils.MockedChangeLog('1.0-1')
         tagformat = 'upstream/%(version)s'
         uversion = '1.1'
+        upstream_branch = 'upstream'
+
 
         self.add_file('doesnot', 'matter')
+        self.repo.create_branch('upstream')
         tag = self.repo.version_to_tag(tagformat, uversion)
         self.repo.create_tag(name=tag, msg="Upstream release %s" % uversion,
                              sign=False)
-
+        self.repo.set_branch("master")
         guessed = dch.guess_version_from_upstream(self.repo,
                                                   tagformat,
+                                                  upstream_branch,
                                                   cp)
         self.assertEqual('1.1-1', guessed)
 
@@ -32,14 +36,43 @@ class TestGuessVersionFromUpstream(testutils.DebianGitTestRepo):
 
         tagformat = 'upstream/%(version)s'
         uversion = '1.1'
+        upstream_branch = 'upstream'
 
         self.add_file('doesnot', 'matter')
+        self.repo.create_branch('upstream')
         tag = self.repo.version_to_tag(tagformat, uversion)
         self.repo.create_tag(name=tag, msg="Upstream release %s" % uversion,
                              sign=False)
 
+        self.repo.set_branch("master")
         guessed = dch.guess_version_from_upstream(self.repo,
                                                   tagformat,
+                                                  upstream_branch,
                                                   cp)
 
         self.assertEqual('1:1.1-1', guessed)
+
+    def test_guess_upstream_tag_clash_with_non_upstream_tag(self):
+        """Guess with clashing upstream- and non-upstream-tag"""
+        cp = testutils.MockedChangeLog('0.9-1')
+
+        tagformat = 'v%(version)s'
+        uversion = '1.0'
+        upstream_branch = 'upstream'
+
+        self.add_file('doesnot', 'matter')
+        self.repo.create_branch('upstream')
+        tag = self.repo.version_to_tag(tagformat, uversion)
+        self.repo.create_tag(name=tag, msg="Upstream release %s" % uversion,
+                             sign=False)
+        self.repo.set_branch("master")
+        self.add_file("clash", "bar")
+        self.repo.create_tag("vyatta/something", msg="some non-upstream tag but not package release tag either")
+        self.add_file("clash2", "bar")
+
+        guessed = dch.guess_version_from_upstream(self.repo,
+                                                  tagformat,
+                                                  upstream_branch,
+                                                  cp)
+
+        self.assertEqual('1.0-1', guessed)
diff --git a/tests/11_test_dch_main.py b/tests/11_test_dch_main.py
index 538d2e84..acea6920 100644
--- a/tests/11_test_dch_main.py
+++ b/tests/11_test_dch_main.py
@@ -57,6 +57,7 @@ class TestScriptDch(DebianGitTestRepo):
         self.repo.create_tag("upstream/0.9", msg="upstream version 0.9")
         self.add_file("bar", "foo")
         self.repo.create_tag("upstream/1.0", msg="upstream version 1.0")
+        self.repo.create_branch("upstream")
         self.repo.create_branch("debian")
         self.repo.set_branch("debian")
         self.upstream_tag = "upstream/%(version)s"
@@ -66,7 +67,7 @@ class TestScriptDch(DebianGitTestRepo):
         self.add_file("debian/changelog", cl_debian)
         self.add_file("debian/control", """Source: test-package\nSection: test\n""")
         self.options = ["--upstream-tag=%s" % self.upstream_tag, "--debian-branch=debian",
-                        "--id-length=0", "--spawn-editor=/bin/true"]
+                        "--upstream-branch=upstream", "--id-length=0", "--spawn-editor=/bin/true"]
         self.repo.create_tag(deb_tag, msg=deb_tag_msg, commit="HEAD~1")
 
 
diff --git a/tests/test_GitRepository.py b/tests/test_GitRepository.py
index 8803e857..83ae8edb 100644
--- a/tests/test_GitRepository.py
+++ b/tests/test_GitRepository.py
@@ -309,6 +309,23 @@ def test_find_tag():
     GitRepositoryError: Can't describe HEAD. Git error: fatal: No names found, cannot describe anything.
     """
 
+def test_find_branch_tag():
+    """
+    Find the closest tags on a certain branch to a given commit
+
+    Methods tested:
+         - L{gbp.git.GitRepository.find_branch_tag}
+
+    >>> import gbp.git
+    >>> repo = gbp.git.GitRepository(repo_dir)
+    >>> repo.find_branch_tag('HEAD', 'master', 'tag*')
+    'tag2'
+    >>> repo.find_branch_tag('HEAD', 'master', 'v*')   # doctest:+ELLIPSIS
+    Traceback (most recent call last):
+    ...
+    GitRepositoryError: Can't describe .... Git error: fatal: No names found, cannot describe anything.
+    """
+
 def test_move_tag():
     """
     Move a tag