Trust only our own comments for the state marker

README.md

@@ -19,8 +19,9 @@ This action tries to fix that in a transparent way. Install it, and hopefully th
 1. Triggers when a PR is squash merged
 2. Finds PRs that were based on the merged branch (direct children only)
 3. Creates a synthetic merge commit with three parents (child tip, deleted branch tip, squash commit) to preserve history without re-introducing code
-4. Updates the direct child PRs to base on trunk now that the bottom change has landed
-5. Pushes updated branches and deletes the merged branch
+4. Pushes the updated branches
+5. Updates the direct child PRs to base on trunk now that the bottom change has landed
+6. Deletes the merged branch
 
 **Note:** Indirect descendants (grandchildren, etc.) are intentionally not modified. Their PR diffs remain correct because the merge-base calculation still works—the synthetic merge commit includes the original parent commit as an ancestor. When their direct parent is eventually merged, they become direct children and get updated at that point.
 

action.yml

@@ -54,6 +54,8 @@ runs:
         MERGED_BRANCH: ${{ github.event.pull_request.head.ref }}
         TARGET_BRANCH: ${{ github.event.pull_request.base.ref }}
         PR_BRANCH: ${{ github.event.pull_request.head.ref }}
+        PR_NUMBER: ${{ github.event.pull_request.number }}
+        PR_BASE: ${{ github.event.pull_request.base.ref }}
       run: |
         echo "Running in $ACTION_MODE mode"
         ${{ github.action_path }}/update-pr-stack.sh

tests/mock_gh.sh

@@ -14,8 +14,8 @@ if [[ "$1" == "pr" && "$2" == "list" ]]; then
     done
 
     if [[ "$base" == "feature1" ]]; then
-        # feature2 is a direct child of feature1
-        echo 'feature2'
+        # feature2 is a direct child of feature1 (PR #2)
+        echo '2 feature2'
     else
         # No other bases have direct children in our test scenario
         :

tests/test_conflict_resolution_resume.sh

@@ -21,8 +21,9 @@ ok() { echo "✅ $1"; PASS=$((PASS+1)); }
 # Build a configurable gh mock in a temp dir. It records every invocation to
 # $CALLS and is driven by env vars set per scenario:
 #   MOCK_LABELS         newline-separated labels returned by `pr view --json labels`
-#   MOCK_BASE           base branch returned by `pr view --json baseRefName`
 #   MOCK_COMMENTS_FILE  file whose contents are returned by `pr view --json comments`
+# The PR's base branch is not mocked: the script must take it from PR_BASE
+# (event payload), so a baseRefName query is an unhandled call and fails.
 make_mock_gh() {
     local dir="$1"
     cat > "$dir/mock_gh.sh" <<'EOF'
@@ -32,8 +33,11 @@ echo "gh $*" >> "$CALLS"
 if [[ "$1 $2" == "pr view" ]]; then
     case "$*" in
         *--json\ labels*)   printf '%s\n' "${MOCK_LABELS:-}";;
-        *--json\ baseRefName*) printf '%s\n' "${MOCK_BASE:-}";;
-        *--json\ comments*) cat "${MOCK_COMMENTS_FILE:-/dev/null}";;
+        *--json\ comments*)
+            # The comments file stands for our own comments only, so the query
+            # must restrict itself to those.
+            [[ "$*" == *viewerDidAuthor* ]] || { echo "comments query must filter by viewerDidAuthor" >&2; exit 1; }
+            cat "${MOCK_COMMENTS_FILE:-/dev/null}";;
         *) echo "unhandled pr view: $*" >&2; exit 1;;
     esac
 elif [[ "$1 $2" == "pr comment" ]]; then
@@ -88,9 +92,9 @@ setup_repo() {
 }
 
 run_resume() {
-    env ACTION_MODE=conflict-resolved PR_BRANCH=child \
+    env ACTION_MODE=conflict-resolved PR_BRANCH=child PR_NUMBER=5 PR_BASE="$PR_BASE" \
         GH="$MOCK_DIR/mock_gh.sh" GIT="$MOCK_DIR/mock_git.sh" \
-        MOCK_LABELS="$MOCK_LABELS" MOCK_BASE="$MOCK_BASE" \
+        MOCK_LABELS="$MOCK_LABELS" \
         MOCK_COMMENTS_FILE="$MOCK_COMMENTS_FILE" CALLS="$CALLS" \
         bash "$ROOT_DIR/update-pr-stack.sh" >"$WORK/out.log" 2>&1 || echo "EXIT=$?" >>"$WORK/out.log"
 }
@@ -103,7 +107,7 @@ marker() { # base target squash
 echo "### Scenario A: user manually retargeted the base -> no mutation"
 setup_repo
 MOCK_LABELS="autorestack-needs-conflict-resolution"
-MOCK_BASE="spark"   # human changed it; marker says parent
+PR_BASE="spark"   # human changed it; marker says parent
 MOCK_COMMENTS_FILE="$WORK/comments.txt"
 { echo "### conflict"; echo; marker parent main "$SQUASH"; } > "$MOCK_COMMENTS_FILE"
 run_resume
@@ -119,7 +123,7 @@ ok "A: manual retarget detected, no branch mutation, label removed"
 echo "### Scenario B: no state marker -> no mutation"
 setup_repo
 MOCK_LABELS="autorestack-needs-conflict-resolution"
-MOCK_BASE="parent"
+PR_BASE="parent"
 MOCK_COMMENTS_FILE="$WORK/comments.txt"
 { echo "### some old conflict comment with no marker"; } > "$MOCK_COMMENTS_FILE"
 run_resume
@@ -137,13 +141,13 @@ setup_repo
 git -C "$WORK" merge -q --no-edit main
 git -C "$WORK" push -q origin child
 MOCK_LABELS="autorestack-needs-conflict-resolution"
-MOCK_BASE="parent"   # matches marker -> not a manual retarget
+PR_BASE="parent"   # matches marker -> not a manual retarget
 MOCK_COMMENTS_FILE="$WORK/comments.txt"
 { echo "### conflict"; echo; marker parent main "$SQUASH"; } > "$MOCK_COMMENTS_FILE"
 run_resume
 
 grep -q -- "git push origin child" "$CALLS" || fail "C: child not pushed"
-grep -q -- "pr edit child --base main" "$CALLS" || fail "C: base not retargeted to main"
+grep -q -- "pr edit 5 --base main" "$CALLS" || fail "C: base not retargeted to main"
 grep -q "remove-label autorestack-needs-conflict-resolution" "$CALLS" || fail "C: label not removed"
 push_line=$(grep -n -- "git push origin child" "$CALLS" | head -1 | cut -d: -f1)
 base_line=$(grep -n -- "--base main" "$CALLS" | head -1 | cut -d: -f1)
@@ -156,7 +160,7 @@ ok "C: resume pushes, retargets base, then removes label"
 echo "### Scenario D: recorded target branch is gone -> give up cleanly"
 setup_repo
 MOCK_LABELS="autorestack-needs-conflict-resolution"
-MOCK_BASE="parent"   # matches marker -> not a manual retarget
+PR_BASE="parent"   # matches marker -> not a manual retarget
 MOCK_COMMENTS_FILE="$WORK/comments.txt"
 { echo "### conflict"; echo; marker parent ghost-target "$SQUASH"; } > "$MOCK_COMMENTS_FILE"
 run_resume
@@ -167,5 +171,20 @@ grep -q -- "--base" "$CALLS" && fail "D: base must NOT be edited"
 [[ "$(git -C "$ORIGIN" rev-parse child)" == "$CHILD_BEFORE" ]] || fail "D: child was pushed"
 ok "D: missing target detected, no branch mutation, label removed"
 
+# ---------------------------------------------------------------------------
+echo "### Scenario E: malformed state marker -> no mutation"
+setup_repo
+MOCK_LABELS="autorestack-needs-conflict-resolution"
+PR_BASE="parent"
+MOCK_COMMENTS_FILE="$WORK/comments.txt"
+{ echo "### conflict"; echo; echo '<!-- autorestack-state: base=parent target=main -->'; } > "$MOCK_COMMENTS_FILE"
+run_resume
+
+grep -q "remove-label autorestack-needs-conflict-resolution" "$CALLS" || fail "E: label not removed"
+grep -q "gh pr comment" "$CALLS" || fail "E: no explanatory comment posted"
+grep -q -- "--base" "$CALLS" && fail "E: base must NOT be edited"
+[[ "$(git -C "$ORIGIN" rev-parse child)" == "$CHILD_BEFORE" ]] || fail "E: child was pushed"
+ok "E: malformed marker handled, no branch mutation, label removed"
+
 echo
 echo "All conflict-resume tests passed 🎉 ($PASS scenarios)"

tests/test_update_pr_stack.sh

@@ -1,6 +1,6 @@
 #!/bin/bash
 
-set -e
+set -eo pipefail
 
 # Get script directory (needed for static mock files)
 SCRIPT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
@@ -71,6 +71,8 @@ echo "Simulated Squash commit (via cherry-pick): $SQUASH_COMMIT"
 
 echo "Running update-pr-stack.sh..."
 # The update script sources command_utils.sh itself
+# Capture stdout+stderr interleaved so command ordering can be asserted.
+RUN_LOG="$TEST_REPO/update_run.log"
 run_update_pr_stack() {
   log_cmd \
     env \
@@ -79,10 +81,24 @@ run_update_pr_stack() {
     TARGET_BRANCH=main \
     GH="$SCRIPT_DIR/mock_gh.sh" \
     GIT="$SCRIPT_DIR/mock_git.sh" \
-    $SCRIPT_DIR/../update-pr-stack.sh
+    $SCRIPT_DIR/../update-pr-stack.sh 2>&1 | tee "$RUN_LOG"
 }
 run_update_pr_stack
 
+# The head must be pushed before the PR is retargeted (a failed push must leave
+# the PR untouched on its old base), and the merged branch deleted only after
+# the retarget (deleting a PR's base branch closes the PR).
+push_line=$(grep -n "git push origin feature2" "$RUN_LOG" | head -1 | cut -d: -f1 || true)
+edit_line=$(grep -n "pr edit 2 --base main" "$RUN_LOG" | head -1 | cut -d: -f1 || true)
+delete_line=$(grep -n "git push origin :feature1" "$RUN_LOG" | head -1 | cut -d: -f1 || true)
+if [[ -n "$push_line" && -n "$edit_line" && -n "$delete_line" \
+      && "$push_line" -lt "$edit_line" && "$edit_line" -lt "$delete_line" ]]; then
+    echo "✅ Ordering: push head, then retarget base, then delete merged branch"
+else
+    echo "❌ Wrong ordering (push=$push_line edit=$edit_line delete=$delete_line)"
+    exit 1
+fi
+
 # Verify the results
 cd "$TEST_REPO"