make list-changes smarter about the "previous" version

The old implementation of list-changes assumed that the deliverable file
included all releases and that they were in order. That assumption does
not hold for independent projects, where the history might not be there
and new entries might be from different branches than the previous
entries, all in the same file. This change uses git to determine the
previous tag for each repository, then shows the right diffs based on
that instead of the assumed tag from the deliverable file.

Change-Id: I122a6ec1792a07cdb23f09a880110dff2446555e
Signed-off-by: Doug Hellmann <doug@doughellmann.com>

openstack_releases/cmds/list_changes.py

@@ -63,8 +63,9 @@ def git_branch_contains(workdir, repo, title, commit):
     header('%s %s' % (title, commit))
     cmd = ['git', 'branch', '-r', '--contains', commit]
     print('\n' + ' '.join(cmd) + '\n')
-    subprocess.check_call(cmd, cwd=os.path.join(workdir, repo))
-    print()
+    out = subprocess.check_output(cmd, cwd=os.path.join(workdir, repo))
+    print(out + '\n')
+    return [o.strip() for o in out.splitlines()]
 
 
 def git_diff(workdir, repo, git_range, file_pattern):
@@ -166,13 +167,17 @@ def main():
         else:
             branch = 'stable/' + series
 
-        # assume the releases are in order and take the last two
+        # assume the releases are in order and take the last one
         new_release = deliverable_info['releases'][-1]
-        if len(deliverable_info['releases']) >= 2:
-            previous_release = deliverable_info['releases'][-2]
-        else:
-            previous_release = None
+
+        # build a map between version numbers and the release details
+        by_version = {
+            str(r['version']): r
+            for r in deliverable_info['releases']
+        }
+
         for project in new_release['projects']:
+
             tag_exists = gitutils.commit_exists(
                 project['repo'],
                 new_release['version'],
@@ -182,7 +187,7 @@ def main():
                       (project['repo'], new_release['version']))
 
             # Check out the code.
-            print('\nChecking out repository')
+            print('\nChecking out repository {}'.format(project['repo']))
             subprocess.check_call(
                 ['zuul-cloner',
                  '--branch', branch,
@@ -192,18 +197,23 @@ def main():
                  ]
             )
 
-            start_range = None
+            # look at the previous tag for the parent of the commit
+            # getting the new release
+            previous_tag = gitutils.get_latest_tag(
+                workdir,
+                project['repo'],
+                '{}^'.format(project['hash'])
+            )
+            previous_release = by_version.get(previous_tag)
+
+            start_range = previous_tag
             if previous_release:
                 previous_project = {
                     x['repo']: x
                     for x in previous_release['projects']
                 }.get(project['repo'])
                 if previous_project is not None:
-                    start_range = previous_project['hash']
-            if not start_range:
-                start_range = (
-                    gitutils.get_latest_tag(workdir, project['repo']) or None
-                )
+                    start_range = previous_tag
 
             if start_range:
                 git_range = '%s..%s' % (start_range, project['hash'])
@@ -229,14 +239,32 @@ def main():
                 ref=project['hash'],
             )
 
-            git_branch_contains(
+            branches = git_branch_contains(
                 workdir=workdir,
                 repo=project['repo'],
                 title='Branches containing commit',
                 commit=project['hash'],
             )
 
-            head_sha = gitutils.sha_for_tag(workdir, project['repo'], 'HEAD')
+            header('Relationship to HEAD')
+            if series == '_independent':
+                interesting_branches = sorted(
+                    b for b in branches
+                    if '->' not in b
+                )
+                head_sha = gitutils.sha_for_tag(
+                    workdir,
+                    project['repo'],
+                    interesting_branches[0],
+                )
+                print('HEAD of {} is {}'.format(interesting_branches[0], head_sha))
+            else:
+                head_sha = gitutils.sha_for_tag(
+                    workdir,
+                    project['repo'],
+                    'HEAD',
+                )
+                print('HEAD of {} is {}'.format(branch, head_sha))
             requested_sha = gitutils.sha_for_tag(
                 workdir,
                 project['repo'],
@@ -247,12 +275,11 @@ def main():
             # git to give us the real SHA for the requested release in
             # case the deliverables file has the short version of the
             # hash.
-            header('Relationship to HEAD')
             if head_sha == requested_sha:
                 print('\nRequest releases from HEAD on %s' % branch)
             else:
                 git_log(workdir, project['repo'], 'Release will NOT include',
-                        '%s..%s~1' % (requested_sha, head_sha),
+                        '%s..%s' % (requested_sha, head_sha),
                         extra_args=['--format=%h %ci %s'])
 
             # Show any requirements changes in the upcoming release.

openstack_releases/gitutils.py

@@ -112,10 +112,13 @@ def check_ancestry(workdir, repo, old_version, sha):
         return False
 
 
-def get_latest_tag(workdir, repo):
+def get_latest_tag(workdir, repo, sha=None):
+    cmd = ['git', 'describe', '--abbrev=0']
+    if sha is not None:
+        cmd.append(sha)
     try:
         return subprocess.check_output(
-            ['git', 'describe', '--abbrev=0'],
+            cmd,
             cwd=os.path.join(workdir, repo),
             stderr=subprocess.STDOUT,
         ).strip()