Address AI feedback

Signed-off-by: Lukasz Gryglicki <[email protected]>

Assisted by [OpenAI](https://platform.openai.com/)

Assisted by [GitHub Copilot](https://github.com/features/copilot)

Author: lukaszgryglicki

cla-backend-go/github/github_repository.go

@@ -1574,7 +1574,7 @@ query($owner:String!, $name:String!, $head:GitObjectID!, $first:Int!, $after:Str
 			break
 		}
 		if !hist.Repository.Object.History.PageInfo.HasNextPage {
-			return nil, false, fmt.Errorf("merge-base commit not found in PR history")
+			return GetPullRequestCommitAuthorsREST(ctx, usersService, installationID, pullRequestID, owner, repo, withCoAuthors)
 		}
 		cur := hist.Repository.Object.History.PageInfo.EndCursor
 		after = &cur

cla-backend/cla/models/github_models.py

@@ -2279,7 +2279,6 @@ def iter_pr_commits_full(g, owner: str, repo_name: str, number: int, page_size:
             # merge-base not found — extremely rare (rebases or unusual ancestry).
             # Fall back to non-GQL old approach (limited to 250 commits but still better that error)
             raise ValueError("merge-base commit not found in PR commit history")
-            # return
 
         after = hist["pageInfo"]["endCursor"]
         safety_pages += 1
@@ -2699,7 +2698,7 @@ def update_pull_request(
         repo = getattr(getattr(pull_request, "base", None), "repo", None)
         commit_obj = repo.get_commit(last_commit_sha)
     except (GithubException, AttributeError, TypeError) as exc:
-        cla.log.error(f"{fn} - PR {pull_request.number}: exception getting base.sha: {exc}")
+        cla.log.error(f"{fn} - PR {pull_request.number}: exception getting commit sha: {exc}")
         try:
             commit_obj = pull_request.get_commits().reversed[0]
             last_commit_sha = commit_obj.sha

cla-backend/cla/utils.py

@@ -1054,7 +1054,7 @@ def assemble_cla_comment(
         missing_user_id=no_user_id,
     )
     body = badge + "<br />" + comment
-    if len(body) > 0xFF00:
+    if len(body.encode('utf-8')) > 0xFF00:
         body = trim_comment(body, max_items=40, head=20, tail=20, ellipsis="…")
     return body