Add workflow to verify code is up-to-date

Author: creydr

.github/workflows/verify-codegen.yml

@@ -0,0 +1,45 @@
+name: Verify
+
+on:
+  pull_request:
+  workflow_dispatch:
+
+jobs:
+  verify:
+    name: Verify Codegen
+
+    runs-on: ubuntu-latest
+    steps:
+      - name: Clone the code
+        uses: actions/checkout@v4
+
+      - name: Setup Go
+        uses: actions/setup-go@v5
+        with:
+          go-version-file: go.mod
+
+      - name: Run Codegen
+        shell: bash
+        env:
+          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
+        run: make update-codegen
+
+      - name: Verify
+        shell: bash
+        run: |
+          # URL encode function for GitHub Actions annotations
+          # From: https://backreference.org/2009/12/23/how-to-match-newlines-in-sed/
+          function urlencode() {
+            sed ':begin;$!N;s/\n/%0A/;tbegin'
+          }
+
+          if [[ -z "$(git status --porcelain)" ]]; then
+            echo "${{ github.repository }} up to date."
+          else
+            echo "Found diffs in: $(git diff-index --name-only HEAD --)"
+            for x in $(git diff-index --name-only HEAD --); do
+              echo "::error file=$x::Please run 'make update-codegen'.%0A$(git diff $x | urlencode)"
+            done
+            echo "Generated code is out of date. Please run 'make update-codegen' and commit the changes."
+            exit 1
+          fi