add scripts/pr_lgtm_scanner.py — LGTM/KO scanner for pr-iphone-deploy

Standalone Python scanner extracted from the inline python in wait-approval. Embedding multi-line Python in a YAML run: | block scalar is fragile: YAML dedents block-scalar content to the first line's indent, which produced both YAML parse failures and Python IndentationErrors in earlier iterations of this workflow. A standalone script file sidesteps all of that and is testable locally.

Behavior preserved:
  - json.loads + \bLGTM\b / \bKO\b word-boundary regex (case-insensitive)
  - skip bot comments tagged with <!-- tabatago:ready-to-test -->
  - KO checked BEFORE LGTM (PR with both signals blocks)

Verified locally across 8 scenarios (bot-only, LGTM, KO, both, empty, usage error, KOM/LGTMX non-match, case-insensitive).

scripts/pr_lgtm_scanner.py

@@ -0,0 +1,70 @@
+#!/usr/bin/env python3
+"""LGTM/KO scanner for the pr-iphone-deploy workflow's wait-approval job.
+
+Reads a Gitea PR comments JSON array (as returned by
+``/api/v1/repos/{owner}/{repo}/issues/{pr}/comments``) on argv[1] and prints
+exactly one of: ``LGTM``, ``KO``, ``PENDING``.
+
+Rules
+-----
+* The bot's own "Ready to test" comment body literally contains the words
+  ``LGTM`` and ``KO`` as instructions to the reviewer — without filtering it
+  out, the workflow would self-merge ~30s after deploy. Bot comments are
+  tagged with the sentinel ``<!-- tabatago:ready-to-test -->`` and skipped.
+* ``KO`` is checked BEFORE ``LGTM`` — a PR with both signals blocks (matches
+  the existing "KO blocks" intent).
+* Word-boundary regex (``\\bLGTM\\b`` / ``\\bKO\\b``, case-insensitive) so
+  "Tested, LGTM!" counts and "KOM" / "LGTMX" do not.
+
+This script lives in ``scripts/`` (not inline in the workflow) because
+embedding multi-line Python inside a YAML ``run: |`` block scalar is fragile:
+YAML dedents block-scalar content to the first line, which produces either a
+YAML parse failure or a Python ``IndentationError`` depending on how the
+body is indented. A standalone file sidesteps all of that.
+"""
+import json
+import re
+import sys
+
+MARKER = "<!-- tabatago:ready-to-test -->"
+LGTM_RE = re.compile(r"\bLGTM\b", re.IGNORECASE)
+KO_RE = re.compile(r"\bKO\b", re.IGNORECASE)
+
+
+def decide(comments_json: str) -> str:
+    """Return 'KO', 'LGTM', or 'PENDING' for the given comments JSON payload."""
+    try:
+        comments = json.loads(comments_json or "[]")
+    except Exception:
+        comments = []
+
+    hit_lgtm = False
+    hit_ko = False
+    for comment in comments:
+        body = comment.get("body") or ""
+        if MARKER in body:
+            # Skip the bot's own "Ready to test" comment — its body mentions
+            # LGTM/KO as instructions and would otherwise self-trigger.
+            continue
+        if KO_RE.search(body):
+            hit_ko = True
+        if LGTM_RE.search(body):
+            hit_lgtm = True
+
+    if hit_ko:
+        return "KO"
+    if hit_lgtm:
+        return "LGTM"
+    return "PENDING"
+
+
+def main() -> int:
+    if len(sys.argv) != 2:
+        print("usage: pr_lgtm_scanner.py <comments_json>", file=sys.stderr)
+        return 2
+    print(decide(sys.argv[1]))
+    return 0
+
+
+if __name__ == "__main__":
+    sys.exit(main())