🐛 fix: reject dual stdin for review suggestions

Author: ShigureNyako

README.md

@@ -245,6 +245,8 @@ gh-llm pr review-submit \
 
 `pr comment-edit`, `issue comment-edit`, `thread-reply`, `review-comment`, `review-suggest`, and `review-submit` all support `--body-file -` to read multi-line text from standard input. `review-suggest` also supports `--suggestion-file -` for the suggestion block itself.
 
+> Note: `review-suggest --body-file - --suggestion-file -` is intentionally rejected because standard input can only be consumed once. Use separate files when both the reason text and suggestion block need external input.
+
 Submit behavior:
 
 - If you already have a pending review on this PR, `review-submit` submits that pending review.

src/gh_llm/commands/options.py

@@ -20,7 +20,7 @@ def resolve_file_or_inline_text(
     default: str = "",
 ) -> str:
     file_path = getattr(args, file_attr, None)
-    if file_path:
+    if file_path is not None:
         return read_text_from_path_or_stdin(str(file_path))
     text = getattr(args, text_attr, None)
     if text is None:

src/gh_llm/commands/pr.py

@@ -361,6 +361,13 @@ def _resolve_suggestion_argument(args: Any) -> str:
     return resolve_file_or_inline_text(args, text_attr="suggestion", file_attr="suggestion_file")
 
 
+def _validate_review_suggest_stdin_sources(args: Any) -> None:
+    if getattr(args, "body_file", None) == "-" and getattr(args, "suggestion_file", None) == "-":
+        raise RuntimeError(
+            "`--body-file -` cannot be combined with `--suggestion-file -`; standard input can only be consumed once"
+        )
+
+
 def _resolve_review_submit_body(args: Any) -> str:
     return _resolve_body_argument(args)
 
@@ -1083,6 +1090,7 @@ def cmd_pr_review_comment(args: Any) -> int:
 
 
 def cmd_pr_review_suggest(args: Any) -> int:
+    _validate_review_suggest_stdin_sources(args)
     client = GitHubClient()
     meta = _resolve_pr_meta(client=client, args=args)
     _validate_pr_head_snapshot(meta=meta, requested_head=_resolve_requested_head(args))

tests/test_cli.py

@@ -2373,6 +2373,41 @@ def test_pr_review_suggest_rejects_suggestion_and_suggestion_file_together(
     assert "argument --suggestion-file: not allowed with argument --suggestion" in err
 
 
+def test_pr_review_suggest_rejects_dual_stdin_inputs(
+    monkeypatch: pytest.MonkeyPatch,
+    capsys: pytest.CaptureFixture[str],
+) -> None:
+    responder = GhResponder()
+    monkeypatch.setattr(github_api.subprocess, "run", responder.run)
+    monkeypatch.setattr(sys, "stdin", _FakeStdin("shared stdin\n"))
+
+    code = cli.run(
+        [
+            "pr",
+            "review-suggest",
+            "--path",
+            "python/test_file.py",
+            "--line",
+            "20",
+            "--side",
+            "RIGHT",
+            "--body-file",
+            "-",
+            "--suggestion-file",
+            "-",
+            "--pr",
+            "77928",
+            "--repo",
+            "PaddlePaddle/Paddle",
+        ]
+    )
+
+    assert code == 1
+    err = capsys.readouterr().err
+    assert "`--body-file -` cannot be combined with `--suggestion-file -`" in err
+    assert not any(call[:3] == ["gh", "api", "graphql"] for call in responder.calls)
+
+
 def _extract_form(cmd: list[str], key: str) -> str:
     for idx, token in enumerate(cmd):
         if token == "-f" and idx + 1 < len(cmd):