local changes

.circleci/OWNERS

@@ -0,0 +1,10 @@
+// For an explanation of the OWNERS rules and syntax, see:
+// https://github.com/ampproject/amp-github-apps/blob/main/owners/OWNERS.example
+
+{
+  rules: [
+    {
+      owners: [{name: 'ampproject/wg-infra'}],
+    },
+  ],
+}

.circleci/check_config.sh

@@ -0,0 +1,57 @@
+#!/bin/bash
+#
+# This script checks if a PR branch is using the most recent CircleCI config.
+# Reference: https://circleci.com/docs/2.0/env-vars/#built-in-environment-variables
+
+set -e
+err=0
+
+GREEN() { echo -e "\033[0;32m$1\033[0m"; }
+RED() { echo -e "\033[0;31m$1\033[0m"; }
+YELLOW() { echo -e "\033[0;33m$1\033[0m"; }
+CYAN() { echo -e "\033[0;36m$1\033[0m"; }
+
+# Push builds are only run against the main, nightly, and amp-release branches.
+if [[ "$CIRCLE_BRANCH" == "main" || "$CIRCLE_BRANCH" == "nightly" || "$CIRCLE_BRANCH" =~ ^amp-release-* ]]; then
+  echo $(GREEN "Nothing to do because $CIRCLE_BRANCH is not a PR branch.")
+  exit 0
+fi
+
+# Check if the PR branch contains the most recent revision the CircleCI config.
+CONFIG_REV=`git rev-list main -1 -- .circleci/config.yml`
+(set -x && git merge-base --is-ancestor $CONFIG_REV $CIRCLE_SHA1) || err=$?
+
+if [[ "$err" -ne "0" ]]; then
+  echo "$(RED "ERROR:") $(CYAN $CIRCLE_BRANCH) is missing the latest CircleCI config revision $(CYAN $CONFIG_REV)."
+  echo -e "\n"
+
+  echo $(YELLOW "This can be fixed in three ways:")
+  echo -e "\n"
+
+  echo "1. Click the $(CYAN "\"Update branch\"") button on GitHub and follow instructions."
+  echo "   ⤷ It can be found towards the bottom of the PR, after the list of checks."
+  echo -e "\n"
+
+  echo "2. Pull the latest commits from $(CYAN "main") and re-push the PR branch."
+  echo "   ⤷ Follow these steps:"
+  echo ""
+  echo "      $(CYAN "git checkout main")"
+  echo "      $(CYAN "git pull")"
+  echo "      $(CYAN "git checkout <PR branch>")"
+  echo "      $(CYAN "git merge main")"
+  echo "      $(CYAN "git push origin")"
+  echo -e "\n"
+
+  echo "3. Rebase on $(CYAN "main") and re-push the PR branch."
+  echo "   ⤷ Follow these steps:"
+  echo ""
+  echo "      $(CYAN "git checkout main")"
+  echo "      $(CYAN "git pull")"
+  echo "      $(CYAN "git checkout <PR branch>")"
+  echo "      $(CYAN "git rebase main")"
+  echo "      $(CYAN "git push origin --force")"
+  echo -e "\n"
+  exit 1
+fi
+
+echo $(GREEN "$CIRCLE_BRANCH is using the latest CircleCI config.")