new_release: use sha from corresponding stable branches

Before the fix, sha values were always extracted from master head, even
when series has a stable branch.

Change-Id: I9810660df7a92c021cd9c154bb3f24d8d828bfd7

openstack_releases/cmds/new_release.py

@@ -104,7 +104,14 @@ def main():
     projects = []
     for project in last_release['projects']:
         gitutils.clone_repo(workdir, project['repo'])
-        sha = gitutils.sha_for_tag(workdir, project['repo'], 'HEAD')
+
+        branches = gitutils.get_branches(workdir, project['repo'])
+        version = 'origin/stable/%s' % series
+        if not any(branch for branch in branches
+                   if branch.endswith(version)):
+            version = 'master'
+
+        sha = gitutils.sha_for_tag(workdir, project['repo'], version)
         projects.append({
             'repo': project['repo'],
             'hash': sha,

openstack_releases/gitutils.py

@@ -113,3 +113,20 @@ def get_latest_tag(workdir, repo):
         print('WARNING failed to retrieve latest tag: %s [%s]' %
               (e, e.output.strip()))
         return None
+
+
+def get_branches(workdir, repo):
+    try:
+        output = subprocess.check_output(
+            ['git', 'branch', '-a'],
+            cwd=os.path.join(workdir, repo),
+            stderr=subprocess.STDOUT,
+        ).strip()
+        return [
+            branch
+            for branch in output.split()
+        ]
+    except subprocess.CalledProcessError as e:
+        print('ERROR failed to retrieve list of branches: %s [%s]' %
+              (e, e.output.strip()))
+        return []