.gitea/scripts/audit-force-merge.sh

@@ -0,0 +1,118 @@
+#!/usr/bin/env bash
+# audit-force-merge — detect a §SOP-6 force-merge after PR close, emit
+# `incident.force_merge` to stdout as structured JSON.
+#
+# Vector's docker_logs source picks up runner stdout; the JSON gets
+# shipped to Loki on molecule-canonical-obs, indexable by event_type.
+# Query example:
+#
+#   {host="operator"} |= "event_type" |= "incident.force_merge" | json
+#
+# A force-merge is detected when a PR closed-with-merged=true had at
+# least one of the repo's required-status-check contexts in a state
+# other than "success" at the merge commit's SHA. That's exactly what
+# the Gitea force_merge:true API call lets through, so it's a faithful
+# detector of the override path.
+#
+# Triggers on `pull_request_target: closed` (loaded from base branch
+# per §SOP-6 security model). No-op when merged=false.
+#
+# Required env (set by the workflow):
+#   GITEA_TOKEN, GITEA_HOST, REPO, PR_NUMBER, REQUIRED_CHECKS
+#
+# REQUIRED_CHECKS is a newline-separated list of status-check context
+# names that branch protection requires. Declared in the workflow YAML
+# rather than fetched from /branch_protections (which needs admin
+# scope — sop-tier-bot has read-only). Trade dynamism for simplicity:
+# when the required-check set changes, update both branch protection
+# AND this env. Keeping them in sync is less complexity than granting
+# the audit bot admin perms on every repo.
+
+set -euo pipefail
+
+: "${GITEA_TOKEN:?required}"
+: "${GITEA_HOST:?required}"
+: "${REPO:?required}"
+: "${PR_NUMBER:?required}"
+: "${REQUIRED_CHECKS:?required (newline-separated context names)}"
+
+OWNER="${REPO%%/*}"
+NAME="${REPO##*/}"
+API="https://${GITEA_HOST}/api/v1"
+AUTH="Authorization: token ${GITEA_TOKEN}"
+
+# 1. Fetch the PR. If not merged, no-op.
+PR=$(curl -sS -H "$AUTH" "${API}/repos/${OWNER}/${NAME}/pulls/${PR_NUMBER}")
+MERGED=$(echo "$PR" | jq -r '.merged // false')
+if [ "$MERGED" != "true" ]; then
+  echo "::notice::PR #${PR_NUMBER} closed without merge — no audit emission."
+  exit 0
+fi
+
+MERGE_SHA=$(echo "$PR" | jq -r '.merge_commit_sha // empty')
+MERGED_BY=$(echo "$PR" | jq -r '.merged_by.login // "unknown"')
+TITLE=$(echo "$PR" | jq -r '.title // ""')
+BASE_BRANCH=$(echo "$PR" | jq -r '.base.ref // "main"')
+HEAD_SHA=$(echo "$PR" | jq -r '.head.sha // empty')
+
+if [ -z "$MERGE_SHA" ]; then
+  echo "::warning::PR #${PR_NUMBER} merged=true but no merge_commit_sha — cannot evaluate force-merge."
+  exit 0
+fi
+
+# 2. Required status checks declared in the workflow env.
+REQUIRED="$REQUIRED_CHECKS"
+if [ -z "${REQUIRED//[[:space:]]/}" ]; then
+  echo "::notice::REQUIRED_CHECKS empty — force-merge not applicable."
+  exit 0
+fi
+
+# 3. Status-check state at the PR HEAD (where checks ran). The merge
+#    commit doesn't get its own checks; we evaluate the PR's last
+#    commit, which is what branch protection compared against.
+STATUS=$(curl -sS -H "$AUTH" \
+  "${API}/repos/${OWNER}/${NAME}/commits/${HEAD_SHA}/status")
+declare -A CHECK_STATE
+while IFS=$'\t' read -r ctx state; do
+  [ -n "$ctx" ] && CHECK_STATE[$ctx]="$state"
+done < <(echo "$STATUS" | jq -r '.statuses // [] | .[] | "\(.context)\t\(.status)"')
+
+# 4. For each required check, was it green at merge? YAML block scalars
+#    (`|`) leave a trailing newline; skip blank/whitespace-only lines.
+FAILED_CHECKS=()
+while IFS= read -r req; do
+  trimmed="${req#"${req%%[![:space:]]*}"}"   # ltrim
+  trimmed="${trimmed%"${trimmed##*[![:space:]]}"}"  # rtrim
+  [ -z "$trimmed" ] && continue
+  state="${CHECK_STATE[$trimmed]:-missing}"
+  if [ "$state" != "success" ]; then
+    FAILED_CHECKS+=("${trimmed}=${state}")
+  fi
+done <<< "$REQUIRED"
+
+if [ "${#FAILED_CHECKS[@]}" -eq 0 ]; then
+  echo "::notice::PR #${PR_NUMBER} merged with all required checks green — not a force-merge."
+  exit 0
+fi
+
+# 5. Emit structured audit event.
+NOW=$(date -u +%Y-%m-%dT%H:%M:%SZ)
+FAILED_JSON=$(printf '%s\n' "${FAILED_CHECKS[@]}" | jq -R . | jq -s .)
+
+# Print as a single-line JSON so Vector's parse_json transform can pick
+# it up cleanly from docker_logs.
+jq -nc \
+  --arg event_type "incident.force_merge" \
+  --arg ts "$NOW" \
+  --arg repo "$REPO" \
+  --argjson pr "$PR_NUMBER" \
+  --arg title "$TITLE" \
+  --arg base "$BASE_BRANCH" \
+  --arg merged_by "$MERGED_BY" \
+  --arg merge_sha "$MERGE_SHA" \
+  --argjson failed_checks "$FAILED_JSON" \
+  '{event_type: $event_type, ts: $ts, repo: $repo, pr: $pr, title: $title,
+    base_branch: $base, merged_by: $merged_by, merge_sha: $merge_sha,
+    failed_checks: $failed_checks}'
+
+echo "::warning::FORCE-MERGE detected on PR #${PR_NUMBER} by ${MERGED_BY}: ${#FAILED_CHECKS[@]} required check(s) not green at merge time."

.gitea/workflows/audit-force-merge.yml

@@ -0,0 +1,58 @@
+# audit-force-merge — emit `incident.force_merge` to runner stdout when
+# a PR is merged with required-status-checks not green. Vector picks
+# the JSON line off docker_logs and ships to Loki on
+# molecule-canonical-obs (per `reference_obs_stack_phase1`); query as:
+#
+#   {host="operator"} |= "event_type" |= "incident.force_merge" | json
+#
+# Closes the §SOP-6 audit gap (the doc says force-merges write to
+# `structure_events`, but that table lives in the platform DB, not
+# Gitea-side; Loki is the practical equivalent for Gitea Actions
+# events). When the credential / observability stack converges later,
+# this can sync into structure_events from Loki via a backfill job —
+# the structured JSON shape is forward-compatible.
+#
+# Logic in `.gitea/scripts/audit-force-merge.sh` per the same script-
+# extract pattern as sop-tier-check.
+
+name: audit-force-merge
+
+# pull_request_target loads from the base branch — same security model
+# as sop-tier-check. Without this, an attacker could rewrite the
+# workflow on a PR and skip the audit emission for their own
+# force-merge. See `.gitea/workflows/sop-tier-check.yml` for the full
+# rationale.
+on:
+  pull_request_target:
+    types: [closed]
+
+jobs:
+  audit:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      pull-requests: read
+    # Skip when PR is closed without merge — saves a runner.
+    if: github.event.pull_request.merged == true
+    steps:
+      - name: Check out base branch (for the script)
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd  # v6.0.2
+        with:
+          ref: ${{ github.event.pull_request.base.sha }}
+      - name: Detect force-merge + emit audit event
+        env:
+          # Same org-level secret the sop-tier-check workflow uses.
+          GITEA_TOKEN: ${{ secrets.SOP_TIER_CHECK_TOKEN || secrets.GITHUB_TOKEN }}
+          GITEA_HOST: git.moleculesai.app
+          REPO: ${{ github.repository }}
+          PR_NUMBER: ${{ github.event.pull_request.number }}
+          # Required-status-check contexts to evaluate at merge time.
+          # Newline-separated. Mirror this against branch protection
+          # (settings → branches → protected branch → required checks).
+          # Declared here rather than fetched from /branch_protections
+          # because that endpoint requires admin write — sop-tier-bot is
+          # read-only by design (least-privilege).
+          REQUIRED_CHECKS: |
+            sop-tier-check / tier-check (pull_request)
+            Secret scan / Scan diff for credential-shaped strings (pull_request)
+        run: bash .gitea/scripts/audit-force-merge.sh