ci: serialize deployments and restore previous release on smoke failure

src/test/ci-deploy-harness.sh

@@ -0,0 +1,44 @@
+# Sourced only by the deployment simulation tests; no external services are used.
+git() {
+  if [ "$1" = rev-parse ]; then printf '%s\n' "$TEST_SHA"; return; fi
+  local n=0
+  if [ -f "$TEST_DIR/remote-count" ]; then read -r n < "$TEST_DIR/remote-count"; fi
+  n=$((n+1)); printf '%s\n' "$n" > "$TEST_DIR/remote-count"
+  if [ "$SCENARIO" = remote-failure ]; then return 1; fi
+  if [ "$SCENARIO" = stale ] || { [ "$SCENARIO" = superseded ] && [ "$n" -gt 1 ]; }; then
+    printf '%s\trefs/heads/main\n' bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb
+  else printf '%s\trefs/heads/main\n' "$TEST_SHA"; fi
+}
+flock() { echo "lock" >> "$TEST_DIR/calls"; [ "$SCENARIO" != lock-failure ]; }
+pnpm() {
+  echo "pnpm $*" >> "$TEST_DIR/calls"
+  if [ "$1" = db:migrate ] && [ "$SCENARIO" = migration-failure ]; then return 1; fi
+  if [ "$1" = test:e2e ] && [ "$SCENARIO" = smoke-failure ]; then return 1; fi
+  return 0
+}
+curl() {
+  if [ "$SCENARIO" = health-failure ] && [ "$(cat "$TEST_DIR/epicnext-cms-app" 2>/dev/null)" = new ]; then return 1; fi
+  echo '{"database":true}'
+}
+sleep() { :; }
+docker() {
+  echo "docker $*" >> "$TEST_DIR/calls"
+  local name="${@: -1}"
+  case "$1" in
+    inspect)
+      [ -f "$TEST_DIR/$name" ] || return 1
+      if [ "${3:-}" = '{{.State.Running}}' ]; then echo true
+      elif [ "${3:-}" = '{{.Image}}' ]; then echo sha256:old
+      fi ;;
+    build) [ "$SCENARIO" != build-failure ] ;;
+    stop) return 0 ;;
+    rename) mv "$TEST_DIR/$2" "$TEST_DIR/$3" ;;
+    run)
+      echo new > "$TEST_DIR/epicnext-cms-app"
+      [ "$SCENARIO" != run-failure ] ;;
+    start) [ -f "$TEST_DIR/$2" ] ;;
+    rm) rm -f "$TEST_DIR/$name" ;;
+    *) return 0 ;;
+  esac
+}
+export -f git flock pnpm curl sleep docker