handle vendor validation

Signed-off-by: CrazyMax <1951866+crazy-max@users.noreply.github.com>

Author: crazy-max

Makefile

@@ -0,0 +1,10 @@
+.PHONY: all
+all:
+
+.PHONY: vendor
+vendor:
+	$(eval $@_TMP_OUT := $(shell mktemp -d -t policy-helpers-output.XXXXXXXXXX))
+	docker buildx bake --set "*.output=type=local,dest=$($@_TMP_OUT)" vendor
+	rm -rf ./vendor
+	cp -R "$($@_TMP_OUT)"/* ./
+	rm -rf "$($@_TMP_OUT)"/*

hack/dockerfiles/vendor.Dockerfile

@@ -5,6 +5,7 @@ ARG ALPINE_VERSION=3.23
 ARG MODOUTDATED_VERSION=v0.9.0
 
 FROM golang:${GO_VERSION}-alpine${ALPINE_VERSION} AS base
+ENV GOFLAGS="-mod=vendor"
 RUN apk add --no-cache git rsync
 WORKDIR /src
 
@@ -15,8 +16,9 @@ RUN --mount=target=/context \
   set -e
   rsync -a /context/. .
   go mod tidy
+  go mod vendor
   mkdir /out
-  cp -r go.mod go.sum /out
+  cp -r go.mod go.sum vendor /out
 EOT
 
 FROM scratch AS update
@@ -28,10 +30,11 @@ RUN --mount=target=/context \
   set -e
   rsync -a /context/. .
   git add -A
+  rm -rf vendor
   cp -rf /out/* .
-  if [ -n "$(git status --porcelain -- go.mod go.sum)" ]; then
-    echo >&2 'ERROR: Vendor result differs. Please vendor your package with "docker buildx bake vendor"'
-    git status --porcelain -- go.mod go.sum
+  if [ -n "$(git status --porcelain -- go.mod go.sum vendor)" ]; then
+    echo >&2 'ERROR: Vendor result differs. Please vendor your package with "make vendor"'
+    git status --porcelain -- go.mod go.sum vendor
     exit 1
   fi
 EOT