Check that generated files are up to date (#1233)

.circleci/config.yml

@@ -30,8 +30,8 @@ jobs:
       - restore_cache:
           keys:
             - go-mod-v1-{{ checksum "go.sum" }}
-            # prebuild runs lint after code generation
-      - run: make prebuild
+      - run: make lint
+      - run: ./hack/verify-generate.sh
       - save_cache:
           key: go-mod-v1-{{ checksum "go.sum" }}
           paths:

hack/verify-generate.sh

@@ -0,0 +1,25 @@
+#!/usr/bin/env bash
+
+set -o nounset
+set -o pipefail
+# intentionally not setting 'set -o errexit' because we want to print custom error messages
+
+# make sure make generate can be invoked
+make generate
+RETVAL=$?
+if [[ ${RETVAL} != 0 ]]; then
+    echo "Invoking 'make generate' ends with non-zero exit code."
+    exit 1
+fi
+
+git diff --exit-code --quiet
+RETVAL=$?
+
+if [[ ${RETVAL} != 0 ]]; then
+    echo "Running 'make generate' produces changes to the current git status. Maybe you forgot to check-in your updated generated files?"
+    echo "The current diff: `git diff`"
+    exit 1
+fi
+
+echo "Verifying 'make generate' was successful! ヽ(•‿•)ノ"
+exit 0