From 743f47eee6425c936b7e249aca9c2c9797b70d39 Mon Sep 17 00:00:00 2001
From: Todd Short <todd.short@me.com>
Date: Mon, 16 Sep 2024 10:57:40 -0400
Subject: [PATCH] Add CI to check if golang version updated

Signed-off-by: Todd Short <todd.short@me.com>
---
 .github/workflows/go-verdiff.yaml | 16 +++++++
 Makefile                          |  5 ++-
 hack/scripts/check-go-version.sh  | 72 +++++++++++++++++++++++++++++++
 3 files changed, 92 insertions(+), 1 deletion(-)
 create mode 100644 .github/workflows/go-verdiff.yaml
 create mode 100755 hack/scripts/check-go-version.sh

diff --git a/.github/workflows/go-verdiff.yaml b/.github/workflows/go-verdiff.yaml
new file mode 100644
index 00000000..4008a7ce
--- /dev/null
+++ b/.github/workflows/go-verdiff.yaml
@@ -0,0 +1,16 @@
+name: go-verdiff
+on:
+  pull_request:
+    paths:
+    - '**.mod'
+    branches:
+    - main
+jobs:
+  go-verdiff:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v4
+      with:
+        fetch-depth: 0
+    - name: Check golang version
+      run: hack/tools/check-go-version.sh "${{ github.event.pull_request.base.sha }}"
diff --git a/Makefile b/Makefile
index c828add2..d0bac37b 100644
--- a/Makefile
+++ b/Makefile
@@ -3,6 +3,8 @@
 SHELL := /usr/bin/env bash -o pipefail
 .SHELLFLAGS := -ec
 
+GOLANG_VERSION := $(shell sed -En 's/^go (.*)$$/\1/p' "go.mod")
+
 ifeq ($(origin IMAGE_REPO), undefined)
 IMAGE_REPO := quay.io/operator-framework/catalogd
 endif
@@ -114,7 +116,8 @@ image-registry: ## Setup in-cluster image registry
 
 .PHONY: tidy
 tidy: ## Update dependencies
-	go mod tidy
+	# Force tidy to use the version already in go.mod
+	go mod tidy -go=$(GOLANG_VERSION)
 
 .PHONY: verify
 verify: tidy fmt vet generate ## Verify the current code generation and lint
diff --git a/hack/scripts/check-go-version.sh b/hack/scripts/check-go-version.sh
new file mode 100755
index 00000000..4482983b
--- /dev/null
+++ b/hack/scripts/check-go-version.sh
@@ -0,0 +1,72 @@
+#!/bin/bash
+
+BASE_REF=${1:-main}
+GO_VER=$(sed -En 's/^go (.*)$/\1/p' "go.mod")
+OLDIFS="${IFS}"
+IFS='.' MAX_VER=(${GO_VER})
+IFS="${OLDIFS}"
+
+if [ ${#MAX_VER[*]} -ne 3 -a ${#MAX_VER[*]} -ne 2 ]; then
+    echo "Invalid go version: ${GO_VER}"
+    exit 1
+fi
+
+GO_MAJOR=${MAX_VER[0]}
+GO_MINOR=${MAX_VER[1]}
+GO_PATCH=${MAX_VER[2]}
+
+RETCODE=0
+
+check_version () {
+    local whole=$1
+    local file=$2
+    OLDIFS="${IFS}"
+    IFS='.' ver=(${whole})
+    IFS="${OLDIFS}"
+
+    if [ ${ver[0]} -gt ${GO_MAJOR} ]; then
+        echo "${file}: ${whole}: Bad golang version (expected ${GO_VER} or less)"
+        return 1
+    fi
+    if [ ${ver[1]} -gt ${GO_MINOR} ]; then
+        echo "${file}: ${whole}: Bad golang version (expected ${GO_VER} or less)"
+        return 1
+    fi
+
+    if [ ${#ver[*]} -eq 2 ] ; then
+        return 0
+    fi
+    if [ ${#ver[*]} -ne 3 ] ; then
+        echo "${file}: ${whole}: Badly formatted golang version"
+        return 1
+    fi
+
+    if [ ${ver[1]} -eq ${GO_MINOR} -a ${ver[2]} -gt ${GO_PATCH} ]; then
+        echo "${file}: ${whole}: Bad golang version (expected ${GO_VER} or less)"
+        return 1
+    fi
+    return 0
+}
+
+echo "Found golang version: ${GO_VER}"
+
+for f in $(find . -name "*.mod"); do
+    v=$(sed -En 's/^go (.*)$/\1/p' ${f})
+    if [ -z ${v} ]; then
+        echo "${f}: Skipping, no version found"
+        continue
+    fi
+    if ! check_version ${v} ${f}; then
+        RETCODE=1
+    fi
+    old=$(git grep -ohP '^go .*$' "${BASE_REF}" -- "${f}")
+    old=${old#go }
+    new=$(git grep -ohP '^go .*$' "${f}")
+    new=${new#go }
+    if [ "${new}" != "${old}" ]; then
+        echo "${f}: ${v}: Updated golang version from ${old}"
+        RETCODE=1
+    fi
+done
+
+exit ${RETCODE}