Fallback to looking up CL issue from triplet_id

In nosquash mode, `git cl` is pretty challenging to use since we don't
have issue numbers. All three parts of the triplet id are readily
available though. This CL adds a fallback to `git cl` which looks up the
issue number by getting the change details by triplet_id.

Change-Id: I0839fe75bcb4bc8d60ff36b4da26dc0e419a1493
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/tools/depot_tools/+/5633186
Commit-Queue: Daniel Rubery <drubery@chromium.org>
Reviewed-by: Gavin Mak <gavinmak@google.com>

gerrit_util.py

@@ -1209,10 +1209,11 @@ def GetChangeUrl(host, change):
     return '%s://%s/a/changes/%s' % (GERRIT_PROTOCOL, host, change)
 
 
-def GetChange(host, change):
+def GetChange(host, change, accept_statuses: Container[int] = frozenset([200])):
     """Queries a Gerrit server for information about a single change."""
     path = 'changes/%s' % change
-    return ReadHttpJsonResponse(CreateHttpConn(host, path))
+    return ReadHttpJsonResponse(CreateHttpConn(host, path),
+                                accept_statuses=accept_statuses)
 
 
 def GetChangeDetail(host, change, o_params=None):

git_cl.py

@@ -1526,11 +1526,41 @@ class Changelist(object):
         self._cached_remote_url = (True, url)
         return url
 
+    def _GetIssueFromTripletId(self):
+        project = self.GetGerritProject()
+        remote, branch = self.GetRemoteBranch()
+        remote_ref = GetTargetRef(remote, branch,
+                                  None).replace("refs/heads/", "")
+        # _create_description_from_log calls into `git log
+        # HEAD^..`. This will exclude everything reachable from `HEAD^`,
+        # leaving just `HEAD`.
+        change_ids = git_footers.get_footer_change_id(
+            _create_description_from_log(["HEAD^"]))
+        if len(change_ids) != 1:
+            return None
+        change_id = change_ids[0]
+        triplet_id = urllib.parse.quote("%s~%s~%s" %
+                                        (project, remote_ref, change_id),
+                                        safe='')
+
+        # GetGerritHost() would attempt to lookup the host from the
+        # issue first, leading to infinite recursion. Instead, use the
+        # fallback of getting the host from the remote URL.
+        gerrit_host = self._GetGerritHostFromRemoteUrl()
+        change = gerrit_util.GetChange(gerrit_host,
+                                       triplet_id,
+                                       accept_statuses=[200, 404])
+        return change.get('_number')
+
     def GetIssue(self):
         """Returns the issue number as a int or None if not set."""
         if self.issue is None and not self.lookedup_issue:
             if self.GetBranch():
                 self.issue = self._GitGetBranchConfigValue(ISSUE_CONFIG_KEY)
+
+            if not settings.GetSquashGerritUploads() and self.issue is None:
+                self.issue = self._GetIssueFromTripletId()
+
             if self.issue is not None:
                 self.issue = int(self.issue)
             self.lookedup_issue = True
@@ -2223,6 +2253,22 @@ class Changelist(object):
             return None
         return urllib.parse.urlparse(remote_url).netloc
 
+    def _GetGerritHostFromRemoteUrl(self):
+        url = urllib.parse.urlparse(self.GetRemoteUrl())
+        parts = url.netloc.split('.')
+
+        # We assume repo to be hosted on Gerrit, and hence Gerrit server
+        # has "-review" suffix for lowest level subdomain.
+        parts[0] = parts[0] + '-review'
+
+        if url.scheme == 'sso' and len(parts) == 1:
+            # sso:// uses abbreivated hosts, eg. sso://chromium instead
+            # of chromium.googlesource.com. Hence, for code review
+            # server, they need to be expanded.
+            parts[0] += '.googlesource.com'
+
+        return '.'.join(parts)
+
     def GetCodereviewServer(self):
         if not self._gerrit_server:
             # If we're on a branch then get the server potentially associated
@@ -2234,20 +2280,7 @@ class Changelist(object):
                     self._gerrit_host = urllib.parse.urlparse(
                         self._gerrit_server).netloc
             if not self._gerrit_server:
-                url = urllib.parse.urlparse(self.GetRemoteUrl())
-                parts = url.netloc.split('.')
-
-                # We assume repo to be hosted on Gerrit, and hence Gerrit server
-                # has "-review" suffix for lowest level subdomain.
-                parts[0] = parts[0] + '-review'
-
-                if url.scheme == 'sso' and len(parts) == 1:
-                    # sso:// uses abbreivated hosts, eg. sso://chromium instead
-                    # of chromium.googlesource.com. Hence, for code review
-                    # server, they need to be expanded.
-                    parts[0] += '.googlesource.com'
-
-                self._gerrit_host = '.'.join(parts)
+                self._gerrit_host = self._GetGerritHostFromRemoteUrl()
                 self._gerrit_server = 'https://%s' % self._gerrit_host
         return self._gerrit_server
 

tests/git_cl_test.py

@@ -933,7 +933,7 @@ class TestGitCl(unittest.TestCase):
             metrics_arguments.append('wip')
 
         # If issue is given, then description is fetched from Gerrit instead.
-        if not title:
+        if not title and squash_mode != "override_nosquash":
             if issue is None:
                 if squash:
                     title = 'Initial upload'
@@ -1249,7 +1249,17 @@ class TestGitCl(unittest.TestCase):
                                                           if issue else None)
         self.mockGit.config['remote.origin.url'] = (
             'https://%s.googlesource.com/my/repo' % short_hostname)
-        self.mockGit.config['user.email'] = 'me@example.com'
+        self.mockGit.config['user.email'] = 'owner@example.com'
+
+        self.calls = []
+        if squash_mode == "override_nosquash":
+            if issue:
+                mock.patch('gerrit_util.GetChange',
+                           return_value={
+                               '_number': issue
+                           }).start()
+            else:
+                mock.patch('gerrit_util.GetChange', return_value={}).start()
 
         self.calls = self._gerrit_base_calls(
             issue=issue,
@@ -3590,6 +3600,16 @@ class TestGitCl(unittest.TestCase):
             change_id='I123456789',
             default_branch='main')
 
+    def test_gerrit_nosquash_with_issue(self):
+        self._run_gerrit_upload_test(
+            [],
+            'desc ✔\n\nBUG=\n\nChange-Id: I123456789\n', [],
+            squash=False,
+            squash_mode='override_nosquash',
+            issue=123456,
+            change_id='I123456789',
+            default_branch='main')
+
 
 class ChangelistTest(unittest.TestCase):
     LAST_COMMIT_SUBJECT = 'Fixes goat teleporter destination to be Australia'