From 6986a9964ae76b46d2007453df8677891d2b5f5b Mon Sep 17 00:00:00 2001
From: donpetry-bot <281750570+donpetry-bot@users.noreply.github.com>
Date: Fri, 26 Jun 2026 23:29:01 +0000
Subject: [PATCH] =?UTF-8?q?feat:=20implement=20issue=20#538=20=E2=80=94=20?=
 =?UTF-8?q?Title:=20pr-review-mention:=20kill=20the=20self-trigger=20?=
 =?UTF-8?q?=E2=80=94=20bot's=20own=20mention-ack=20re-fires=20the=20listen?=
 =?UTF-8?q?er?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../workflows/pr-review-mention-reusable.yml  | 16 ++++-
 .github/workflows/pr-review-mention-tests.yml | 55 +++++++++++++++
 .../pr-review-mention/helpers/setup.bash      | 29 ++++++++
 .../pr-review-mention/self-trigger.bats       | 68 +++++++++++++++++++
 4 files changed, 166 insertions(+), 2 deletions(-)
 create mode 100644 .github/workflows/pr-review-mention-tests.yml
 create mode 100644 test/workflows/pr-review-mention/helpers/setup.bash
 create mode 100644 test/workflows/pr-review-mention/self-trigger.bats

diff --git a/.github/workflows/pr-review-mention-reusable.yml b/.github/workflows/pr-review-mention-reusable.yml
index 2aa7bfa2..8fc46174 100644
--- a/.github/workflows/pr-review-mention-reusable.yml
+++ b/.github/workflows/pr-review-mention-reusable.yml
@@ -37,12 +37,20 @@ jobs:
     # team review requests; comment fields don't exist on pull_request events.
     # For comment events we also gate at the job level on author_association so
     # that the job (and its secrets) never start for external/untrusted actors.
+    #
+    # Self-trigger guard (#538): a comment authored by donpetry-bot, or one
+    # carrying a `<!-- pr-review-agent ... -->` marker, is the agent talking
+    # about its own work and must never re-fire the listener. Without this the
+    # mention-ack (@-mention authored by the bot, marker-tagged) re-triggers the
+    # cascade — the #860 runaway (1,481 identical acks at ~9s for ~4.5h).
     if: |
       (github.event_name == 'pull_request' &&
        github.event.requested_reviewer != null &&
        github.event.requested_reviewer.login == 'donpetry-bot' &&
        github.event.pull_request.head.repo.full_name == github.repository) ||
       (github.event_name != 'pull_request' &&
+       github.event.comment.user.login != 'donpetry-bot' &&
+       !contains(github.event.comment.body, '<!-- pr-review-agent') &&
        contains(github.event.comment.body, '@donpetry-bot') &&
        contains(fromJSON('["OWNER","MEMBER","COLLABORATOR"]'), github.event.comment.author_association) &&
        (github.event_name == 'pull_request_review_comment' ||
@@ -134,12 +142,16 @@ jobs:
           GH_TOKEN: ${{ secrets.DON_PETRY_BOT_GH_PAT }}
           PR_URL: ${{ steps.pr.outputs.pr_url }}
         run: |
+          # Reference the actor in PLAIN TEXT (no leading @): a literal @-mention
+          # fires a mention webhook, and an ack that ever named the bot would
+          # re-trigger this listener. Defense-in-depth alongside the job `if:`
+          # self-trigger guard above (#538 / #860).
           if [ "${{ github.event_name }}" = "pull_request" ]; then
             ACTOR="${{ github.event.sender.login }}"
-            MSG="@${ACTOR} assigned me as reviewer — starting a fresh review now. Results will appear in a few minutes."
+            MSG="${ACTOR} assigned me as reviewer — starting a fresh review now. Results will appear in a few minutes."
           else
             ACTOR="${{ github.event.comment.user.login }}"
-            MSG="@${ACTOR} I'm on it — starting a fresh review now. Results will appear in a few minutes."
+            MSG="${ACTOR} I'm on it — starting a fresh review now. Results will appear in a few minutes."
           fi
           gh pr comment "$PR_URL" --body "$(printf '<!-- pr-review-agent mention-ack -->\n%s' "${MSG}")"
 
diff --git a/.github/workflows/pr-review-mention-tests.yml b/.github/workflows/pr-review-mention-tests.yml
new file mode 100644
index 00000000..548e1de0
--- /dev/null
+++ b/.github/workflows/pr-review-mention-tests.yml
@@ -0,0 +1,55 @@
+# Quality gate for the reusable pr-review-mention workflow.
+#
+# Triggered on any PR that touches:
+#   - .github/workflows/pr-review-mention*.yml
+#   - test/workflows/pr-review-mention/**
+#   - standards/workflows/pr-review-mention.yml
+#
+# Gate (must pass before merge):
+#   1. bats — contract tests for the self-trigger guard and ack text (#538)
+#
+# Standard: this workflow pins the anti-self-trigger contract from issue #538
+# (the org-repo half of the #860 mention-ack runaway).
+
+name: PR Review Mention Tests
+
+on:
+  pull_request:
+    paths:
+      - '.github/workflows/pr-review-mention*.yml'
+      - 'test/workflows/pr-review-mention/**'
+      - 'standards/workflows/pr-review-mention.yml'
+  push:
+    branches:
+      - main
+    paths:
+      - '.github/workflows/pr-review-mention*.yml'
+      - 'test/workflows/pr-review-mention/**'
+      - 'standards/workflows/pr-review-mention.yml'
+
+permissions:
+  contents: read
+
+concurrency:
+  group: pr-review-mention-tests-${{ github.ref }}
+  cancel-in-progress: true
+
+jobs:
+  test:
+    name: bats
+    runs-on: ubuntu-latest
+    timeout-minutes: 10
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@9c091bb21b7c1c1d1991bb908d89e4e9dddfe3e0 # v7.0.0
+        with:
+          fetch-depth: 1
+
+      - name: Install bats
+        run: |
+          set -euo pipefail
+          sudo apt-get update -qq
+          sudo apt-get install -y --no-install-recommends bats
+
+      - name: Run bats suite
+        run: bats --print-output-on-failure test/workflows/pr-review-mention/
diff --git a/test/workflows/pr-review-mention/helpers/setup.bash b/test/workflows/pr-review-mention/helpers/setup.bash
new file mode 100644
index 00000000..9b8ed0ac
--- /dev/null
+++ b/test/workflows/pr-review-mention/helpers/setup.bash
@@ -0,0 +1,29 @@
+# Common test helpers for the pr-review-mention bats suite.
+
+# Repo root, regardless of where bats is invoked from.
+TT_REPO_ROOT="$(cd -- "$(dirname -- "${BASH_SOURCE[0]}")/../../../.." && pwd)"
+export TT_REPO_ROOT
+
+# The reusable workflow that owns all mention-dispatch logic (the file under test).
+TT_REUSABLE="${TT_REPO_ROOT}/.github/workflows/pr-review-mention-reusable.yml"
+export TT_REUSABLE
+
+# Print the job-level `if:` guard block: everything from the `if: |` line up to
+# (but not including) the `steps:` key of the handle-mention job.
+prm_if_guard() {
+  awk '
+    /^[[:space:]]*if:[[:space:]]*\|/ { grab=1; next }
+    grab && /^[[:space:]]*steps:[[:space:]]*$/ { exit }
+    grab { print }
+  ' "$TT_REUSABLE"
+}
+
+# Print the body of the "Post acknowledgement comment" step: everything from that
+# step's `- name:` line up to (but not including) the next `- name:` line.
+prm_ack_step() {
+  awk '
+    /^[[:space:]]*-[[:space:]]*name:[[:space:]]*Post acknowledgement comment/ { grab=1; print; next }
+    grab && /^[[:space:]]*-[[:space:]]*name:/ { exit }
+    grab { print }
+  ' "$TT_REUSABLE"
+}
diff --git a/test/workflows/pr-review-mention/self-trigger.bats b/test/workflows/pr-review-mention/self-trigger.bats
new file mode 100644
index 00000000..ac707b43
--- /dev/null
+++ b/test/workflows/pr-review-mention/self-trigger.bats
@@ -0,0 +1,68 @@
+#!/usr/bin/env bats
+# Contract tests for .github/workflows/pr-review-mention-reusable.yml
+#
+# Pins issue #538: the mention listener must never trigger on its own work.
+# The pr-review ack comment is authored by donpetry-bot and carries a
+# `<!-- pr-review-agent ... -->` marker; either property must keep the job's
+# `if:` gate (and its secrets) from ever starting. The ack must also fire no
+# mention webhook (#860 runaway: 1,481 byte-identical acks at ~9s cadence).
+
+load 'helpers/setup'
+
+@test "reusable workflow file exists" {
+  [ -f "$TT_REUSABLE" ]
+}
+
+# ── Acceptance 1: bot-authored / marker comments never re-trigger ─────────────
+
+@test "if-guard excludes comments authored by the bot itself" {
+  run prm_if_guard
+  [ "$status" -eq 0 ]
+  [[ "$output" == *"github.event.comment.user.login != 'donpetry-bot'"* ]]
+}
+
+@test "if-guard excludes comments carrying a pr-review-agent marker" {
+  run prm_if_guard
+  [ "$status" -eq 0 ]
+  [[ "$output" == *"!contains(github.event.comment.body, '<!-- pr-review-agent')"* ]]
+}
+
+@test "if-guard still requires an @donpetry-bot mention to fire (trigger preserved)" {
+  run prm_if_guard
+  [ "$status" -eq 0 ]
+  [[ "$output" == *"contains(github.event.comment.body, '@donpetry-bot')"* ]]
+}
+
+@test "if-guard still gates on trusted author_association (trust gate preserved)" {
+  run prm_if_guard
+  [ "$status" -eq 0 ]
+  [[ "$output" == *'["OWNER","MEMBER","COLLABORATOR"]'* ]]
+}
+
+# ── Acceptance 2: the ack comment fires no mention webhook ────────────────────
+
+@test "ack step never @-mentions any user (no mention webhook)" {
+  run prm_ack_step
+  [ "$status" -eq 0 ]
+  # A mention webhook fires only on a literal `@handle`. The ack must reference
+  # the actor as plain text, so no `@$` / `@${` interpolation may remain.
+  [[ "$output" != *'@$'* ]]
+}
+
+@test "ack step never literally @-mentions donpetry-bot" {
+  run prm_ack_step
+  [ "$status" -eq 0 ]
+  [[ "$output" != *"@donpetry-bot"* ]]
+}
+
+@test "ack step still tags its comment with the pr-review-agent marker" {
+  run prm_ack_step
+  [ "$status" -eq 0 ]
+  [[ "$output" == *"<!-- pr-review-agent mention-ack -->"* ]]
+}
+
+@test "ack step still names the actor in the acknowledgement (plain text)" {
+  run prm_ack_step
+  [ "$status" -eq 0 ]
+  [[ "$output" == *'${ACTOR}'* ]]
+}