fix: strip [skip ci] tokens and prefer newest commit in squash titles

docs/specs/DEVX-179.md

@@ -0,0 +1,49 @@
+# DEVX-179: auto-merge must never select `[skip ci]` squash titles
+
+## Problem
+
+PR #351 squash-merged as `DEVX-178: chore: update badge URLs to commit
+4422c70b [skip ci]`. `extract_conventional_msg` picked a commit subject
+carrying `[skip ci]` — a master badge commit surfaced in the PR's commit
+list after force-push/amend rewrote branch history. The resulting merge
+commit suppressed the post-merge push run: no release, no publish, no
+wiki sync, no Vikunja close.
+
+PR #352 shows the secondary defect: two `ci:` commits on the branch and
+the older one won the tie, so the squash title described a throwaway
+retrigger commit instead of the real change.
+
+## Approach
+
+REQ-1: Subjects containing `[skip ci]`, `[ci skip]`, or `[skip actions]`
+(case-insensitive) are ineligible merge titles. They are excluded before
+priority scoring, so a badge/chore/`[skip ci]` commit can never suppress
+the post-merge pipeline again.
+
+REQ-2: Equal-priority ties resolve to the newest commit in the returned
+list (Gitea returns PR commits newest-first; iterate in returned order
+and keep the first best candidate).
+
+## Test Plan
+
+- `test_auto_merge.py`: commits `[ci retrigger, badge-chore-skipci]` →
+  the `ci` subject wins; commits `[older-ci, newer-ci]` → newest wins;
+  all commits `[skip ci]` → falls back to newest non-skipped subject.
+- `make pytest-cov` (100% gate), `make lint-all`.
+
+## Deploy Plan
+
+Merge as `fix:` → post-merge cuts a release that also ships DEVX-178's
+PLAYBOOK_ROLE_MAP entry.
+
+## Rollback Plan
+
+Revert the squash commit; extract behavior returns to the previous
+(unhardened) selection.
+
+## Acceptance Criteria
+
+- [x] REQ-1: `[skip ci]`/`[ci skip]`/`[skip actions]` subjects are never
+  selected.
+- [x] REQ-2: Equal-priority ties pick the newest commit.
+- [x] Unit tests cover both; 100% coverage maintained.

src/devx/ci/auto_merge.py

@@ -184,22 +184,31 @@ def validate_pr_title_matches_vikunja(pr_title: str, task_id: str) -> None:
         )
 
 
+# Subjects carrying these tokens suppress post-merge CI entirely — strip them
+# before a commit message can become the squash title (see DEVX-179).
+_SKIP_CI_RE = re.compile(r"\s*\[(?:ci skip|skip ci|skip actions|actions skip|skip)\]", re.IGNORECASE)
+
+
 def extract_conventional_msg(commits: list[dict[str, Any]]) -> str:
     """Extract the conventional commit message from PR commits.
 
     Picks the highest-priority conventional commit message from the PR.
-    Priority: feat > fix > refactor > docs > chore > other.
-    Falls back to the newest commit message if none match.
+    Priority: feat > fix > refactor > docs > chore > other. The Gitea
+    ``/pulls/{n}/commits`` endpoint returns commits newest-first, so the
+    first best-scoring subject wins equal-priority ties.
+    ``[skip ci]``-style tokens are stripped from every candidate so the
+    merge title can never suppress the post-merge release pipeline.
     """
     priority = {"feat": 5, "fix": 4, "refactor": 3, "docs": 2, "chore": 1, "ci": 1, "style": 1, "test": 1}
     best_msg = ""
     best_score = 0
-    for commit in reversed(commits):
+    for commit in commits:
         commit_info = commit.get("commit", {})
         message = str(commit_info.get("message", "") if isinstance(commit_info, dict) else "").split("\n")[0]
         # Strip any leading task ID prefix (e.g. "OBL-INFRA-364: fix: ...") so
-        # conventional commit matching works on the remainder.
-        stripped = _TASK_ID_PREFIX_RE.sub("", message)
+        # conventional commit matching works on the remainder; drop CI-skip
+        # tokens so they never reach the merge title.
+        stripped = _SKIP_CI_RE.sub("", _TASK_ID_PREFIX_RE.sub("", message)).strip()
         m = CONVENTIONAL_RE.match(stripped)
         if m:
             prefix = m.group(1).split("(")[0].strip()  # e.g. "feat" from "feat(scope)"
@@ -209,11 +218,11 @@ def extract_conventional_msg(commits: list[dict[str, Any]]) -> str:
                 best_msg = stripped
     if best_msg:
         return best_msg
-    # Fallback: use the newest commit's first line (strip task ID prefix if present)
+    # Fallback: the newest commit's first line (newest-first API order).
     if commits:
-        commit_info = commits[-1].get("commit", {})
+        commit_info = commits[0].get("commit", {})
         raw = str(commit_info.get("message", "") if isinstance(commit_info, dict) else "").split("\n")[0]
-        return _TASK_ID_PREFIX_RE.sub("", raw)
+        return _SKIP_CI_RE.sub("", _TASK_ID_PREFIX_RE.sub("", raw)).strip()
     return ""
 
 

tests/unit/test_auto_merge.py

@@ -232,6 +232,40 @@ class TestExtractConventionalMsg:
         ]
         assert extract_conventional_msg(commits) == "random message"
 
+    def test_skip_ci_subjects_are_ineligible(self) -> None:
+        """[skip ci] commits must never become the merge title (REQ-1)."""
+        commits = [
+            {"commit": {"message": "ci: retrigger validation"}},
+            {"commit": {"message": "chore: update badge URLs to commit abc123 [skip ci]"}},
+        ]
+        assert extract_conventional_msg(commits) == "ci: retrigger validation"
+
+    def test_skip_ci_variants_excluded(self) -> None:
+        """All skip-token spellings are ineligible."""
+        for token in ("[skip ci]", "[ci skip]", "[skip actions]", "[actions skip]", "[SKIP CI]"):
+            commits = [
+                {"commit": {"message": "feat: real change"}},
+                {"commit": {"message": f"chore: noise {token}"}},
+            ]
+            assert extract_conventional_msg(commits) == "feat: real change"
+
+    def test_tie_prefers_newest_commit(self) -> None:
+        """Equal-priority ties resolve to the newest commit (REQ-2); the
+        API returns commits newest-first."""
+        commits = [
+            {"commit": {"message": "ci: add workflow_dispatch trigger"}},
+            {"commit": {"message": "ci: retrigger validation"}},
+        ]
+        assert extract_conventional_msg(commits) == "ci: add workflow_dispatch trigger"
+
+    def test_all_skip_ci_fallback_strips_token(self) -> None:
+        """When every commit carries [skip ci], the token is stripped so
+        the merge still triggers post-merge."""
+        commits = [
+            {"commit": {"message": "chore: noise [skip ci]"}},
+        ]
+        assert extract_conventional_msg(commits) == "chore: noise"
+
 
 # -- run_cmd --