pw_presubmit: Loosen commit message checks for Copybara imports

Change-Id: I1f4349128be485f2a9c59b7309d2b2e53506a09b
Reviewed-on: https://pigweed-review.googlesource.com/c/pigweed/pigweed/+/106711
Pigweed-Auto-Submit: Wyatt Hepler <[email protected]>
Commit-Queue: Auto-Submit <[email protected]>
Reviewed-by: Rob Mohr <[email protected]>

pw_presubmit/py/pw_presubmit/pigweed_presubmit.py

@@ -662,17 +662,17 @@ def commit_message_format(_: PresubmitContext):
     for line in lines:
         _LOG.debug(line)
 
+    if not lines:
+        _LOG.error('The commit message is too short!')
+        raise PresubmitFailure
+
     # Ignore Gerrit-generated reverts.
     if ('Revert' in lines[0]
             and 'This reverts commit ' in git_repo.commit_message()
             and 'Reason for revert: ' in git_repo.commit_message()):
         _LOG.warning('Ignoring apparent Gerrit-generated revert')
         return
 
-    if not lines:
-        _LOG.error('The commit message is too short!')
-        raise PresubmitFailure
-
     errors = 0
 
     if len(lines[0]) > 72:
@@ -694,6 +694,13 @@ def commit_message_format(_: PresubmitContext):
                      lines[1])
         errors += 1
 
+    # Ignore the line length check for Copybara imports so they can include the
+    # commit hash and description for imported commits.
+    if not errors and ('Copybara import' in lines[0]
+                       and 'GitOrigin-RevId:' in git_repo.commit_message()):
+        _LOG.warning('Ignoring Copybara import')
+        return
+
     # Check that the lines are 72 characters or less, but skip any lines that
     # might possibly have a URL, path, or metadata in them. Also skip any lines
     # with non-ASCII characters.