Fix git-review -d behavior with branches

- Fix fetch_review to use the information from the correct branch.
- Improve the unit test for git review -d to exercice the backport
workflow using branches.

Change-Id: I47c2e0149648a1f4f558e7f1ad6204f7f551865a
Closes-Bug: #2000294

git_review/cmd.py

@@ -1104,7 +1104,16 @@ def fetch_review(review, masterbranch, remote):
 
     if not len(review_infos):
         raise ReviewInformationNotFound(review)
-    review_info = review_infos[0]
+    for info in review_infos:
+        if 'branch' in info and info['branch'] == masterbranch:
+            if VERBOSE:
+                print('Using review info from branch %s' % info['branch'])
+            review_info = info
+            break
+    else:
+        review_info = review_infos[0]
+        if VERBOSE and 'branch' in review_info:
+            print('Using default branch %s' % review_info['branch'])
 
     try:
         if patchset_number is None:

git_review/tests/__init__.py

@@ -198,6 +198,15 @@ class BaseGitReviewTestCase(testtools.TestCase, GerritHelpers):
         self._run_git('add', '--all')
         self._run_git('commit', '-m', 'Test file and .gitreview added.')
         self._run_git('push', 'origin', 'master')
+        # push a branch to gerrit
+        self._run_git('checkout', '-b', 'testbranch')
+        utils.write_to_file(self._dir('test', 'test_file.txt'),
+                            'test file branched'.encode())
+        self._create_gitreview_file(defaultbranch='testbranch')
+        self._run_git('add', '--all')
+        self._run_git('commit', '-m', 'Branched.')
+        self._run_git('push', 'origin', 'testbranch')
+        # cleanup
         shutil.rmtree(self.test_dir)
 
         # go to the just cloned test Git repository

git_review/tests/test_git_review.py

@@ -118,7 +118,20 @@ class GitReviewTestCase(tests.BaseGitReviewTestCase):
         self._run_git_review('-d', change_id)
         self.assertIn('test commit message', self._run_git('log', '-1'))
 
-        # second download should also work correct
+        # test backport branch
+        self._run_git('checkout', '-b', 'mybackport',
+                      self._remote + '/' + 'testbranch')
+        self._simple_change('test file modified in branch',
+                            'test branch commit message\n\nChange-Id: %s' %
+                            change_id)
+        self._run_git_review('testbranch')
+        self._run_git('checkout', 'master')
+        self._run_git_review('-d', change_id, 'testbranch')
+        self.assertIn('test branch commit message',
+                      self._run_git('log', '-1'))
+
+        # second download should also work correctly
+        self._run_git('checkout', 'master')
         self._run_git_review('-d', change_id)
         self.assertIn('test commit message', self._run_git('show', 'HEAD'))
         self.assertNotIn('test commit message',