fix(robomp): thread commit_id/head_sha/patch through proxy backend

Follow-up fix round for 71d608aae6 (validate PR review comment
anchors against the diff before submitting). The validation path
broke in several places the original commit did not cover:

- GitHubBackend.submit_review gained no commit_id parameter, so
  submitting through GitHubProxyClient raised a production
  TypeError on a path the validation code depended on.
- PullRequestInfo lacked head_sha, so the Forgejo commit_id
  fallback raised AttributeError; it is now parsed in
  _pr_from_payload and carried through the proxy round-trip.
- _pr_file_from dropped the file patch, silently no-oping anchor
  validation for anything routed through the proxy; the patch is
  now forwarded.
- The hunk parser treated any +++/--- line as a file header,
  desyncing line counters when added/removed content began with
  those prefixes; file headers are now recognized only before
  the first hunk.
- Reworded the comment to "Forgejo only" to match the actual
  backend behavior.

Adds tests for forgejo commit_id fetch, fallback double-failure,
empty-patch fail-open, LEFT-side anchoring, proxy commit_id
validation, and file-creation hunk boundaries.

python/robomp/src/github_backend.py

@@ -100,6 +100,7 @@ class GitHubBackend(Protocol):
         body: str,
         event: str,
         comments: list[Mapping[str, Any]],
+        commit_id: str | None = None,
     ) -> PullRequestReviewInfo: ...
 
     async def add_assignees(self, repo: str, number: int, assignees: list[str]) -> None: ...

python/robomp/src/github_client.py

@@ -69,6 +69,7 @@ class PullRequestInfo:
     head_repo: str = ""
     title: str = ""
     body: str = ""
+    head_sha: str = ""
 
 
 @dataclass(slots=True, frozen=True)
@@ -592,7 +593,7 @@ class GitHubClient:
     def _review_comments_payload(self, comments: list[Mapping[str, Any]]) -> list[dict[str, Any]]:
         """Adapt canonical host-tool comment shape to the wire schema for this platform.
 
-        GitHub keeps line/side/start_line/start_side; Forgejo/Gitea only reads
+        GitHub keeps line/side/start_line/start_side; Forgejo only reads
         path/body/new_position (+old_position), so github-only keys are dropped
         and `line` is mapped to `new_position` for RIGHT-side comments or
         `old_position` for LEFT-side (removed-line) comments.
@@ -798,6 +799,7 @@ def _pr_from_payload(repo: str, data: Mapping[str, Any]) -> PullRequestInfo:
         head_repo=str(head_repo.get("full_name") or "") if isinstance(head_repo, Mapping) else "",
         title=str(data.get("title") or ""),
         body=str(data.get("body") or ""),
+        head_sha=str(head.get("sha") or "") if isinstance(head, Mapping) else "",
     )
 
 

python/robomp/src/host_tools.py

@@ -1760,9 +1760,15 @@ def _diff_anchorable_lines(patch: str) -> tuple[frozenset[int], frozenset[int]]:
             old_line = int(m.group(1))
             new_line = int(m.group(2))
             continue
-        if raw.startswith("+++") or raw.startswith("---") or raw.startswith("\\"):
+        if raw.startswith("\\"):
             continue
-        if new_line is None or old_line is None:
+        # `+++`/`---` are file headers only before the first hunk. Inside a
+        # hunk a diff line's *content* may start with `++` (added) or `--`
+        # (removed), and those lines must advance the counters.
+        in_hunk = new_line is not None and old_line is not None
+        if raw.startswith(("+++", "---")) and not in_hunk:
+            continue
+        if not in_hunk:
             continue
         if raw.startswith("+"):
             right.add(new_line)
@@ -1778,9 +1784,7 @@ def _diff_anchorable_lines(patch: str) -> tuple[frozenset[int], frozenset[int]]:
     return frozenset(right), frozenset(left)
 
 
-def _filter_anchorable_comments(
-    staged: list[Any], files: list[PullRequestFileInfo]
-) -> tuple[list[Any], list[Any]]:
+def _filter_anchorable_comments(staged: list[Any], files: list[PullRequestFileInfo]) -> tuple[list[Any], list[Any]]:
     """Partition staged comments into (anchorable, dropped) by diff hunk membership."""
     by_path = {f.path: f for f in files}
     cache: dict[str, tuple[frozenset[int], frozenset[int]]] = {}

python/robomp/src/proxy/server.py

@@ -671,6 +671,8 @@ def create_proxy_app(settings: Settings) -> FastAPI:
         body = _require_str(data.get("body"), "body")
         event = str(data.get("event") or "COMMENT")
         comments = _require_review_comments(data.get("comments"))
+        commit_id_raw = data.get("commit_id")
+        commit_id = commit_id_raw if isinstance(commit_id_raw, str) and commit_id_raw else None
         github: GitHubClient = request.app.state.github
         try:
             review = await github.submit_pr_review(
@@ -679,6 +681,7 @@ def create_proxy_app(settings: Settings) -> FastAPI:
                 body=body,
                 event=event,
                 comments=comments,
+                commit_id=commit_id,
             )
         except GitHubError as exc:
             return _gh_error_response(exc)

python/robomp/src/proxy_client.py

@@ -334,17 +334,21 @@ class GitHubProxyClient:
         body: str,
         event: str,
         comments: list[Mapping[str, Any]],
+        commit_id: str | None = None,
     ) -> PullRequestReviewInfo:
+        json_body: dict[str, Any] = {
+            "repo": repo,
+            "pr_number": pr_number,
+            "body": body,
+            "event": event,
+            "comments": comments,
+        }
+        if commit_id:
+            json_body["commit_id"] = commit_id
         data = await self._request(
             "POST",
             "/gh/v1/submit_pr_review",
-            json_body={
-                "repo": repo,
-                "pr_number": pr_number,
-                "body": body,
-                "event": event,
-                "comments": comments,
-            },
+            json_body=json_body,
         )
         return _pr_review_from(data)
 
@@ -602,6 +606,7 @@ def _pr_file_from(data: Any) -> PullRequestFileInfo:
         status=str(data.get("status") or ""),
         additions=int(data.get("additions") or 0),
         deletions=int(data.get("deletions") or 0),
+        patch=str(data.get("patch") or ""),
     )
 
 
@@ -619,6 +624,7 @@ def _pr_from(data: Any) -> PullRequestInfo:
         head_repo=str(data.get("head_repo") or ""),
         title=str(data.get("title") or ""),
         body=str(data.get("body") or ""),
+        head_sha=str(data.get("head_sha") or ""),
     )