Add validation of new protoc against Jaeger repos

.github/workflows/build-and-publish.yml

@@ -1,15 +1,17 @@
 name: Docker Image
 on:
   push:
-    tags:
-      - '**'
-    branches:
-      - main
+    branches: [main]
   pull_request:
+    branches: [main]
     paths:
-      - .github/workflows/jaeger-dockerimage.yml
-      - Dockerfile
-      - protoc-wrapper
+    - .github/workflows/jaeger-dockerimage.yml
+    - Dockerfile
+    - protoc-wrapper
+  release:
+    types: [published]
+  # allow running release workflow manually
+  workflow_dispatch:
 
 jobs:
   build:
@@ -56,3 +58,34 @@ jobs:
         cache-from: type=gha
         cache-to: type=gha,mode=max
         platforms: linux/amd64,linux/arm64
+
+    # The following steps run only on pull requests and validate
+    # that the new image can run successfully in Jaeger repos.
+    # We do not check if the generated files would be different there,
+    # only that the build does not fail.
+
+    - name: Checkout Jaeger for validation
+      if: github.event_name == 'pull_request'
+      uses: actions/checkout@v4
+      with:
+        repository: jaegertracing/jaeger
+        submodules: recursive
+        path: jaeger
+
+    - name: Build Proto in Jaeger
+      if: github.event_name == 'pull_request'
+      working-directory: jaeger
+      run: make proto JAEGER_DOCKER_PROTOBUF=protobuf
+
+    - name: Checkout jaeger-idl for validation
+      if: github.event_name == 'pull_request'
+      uses: actions/checkout@v4
+      with:
+        repository: jaegertracing/jaeger-idl
+        submodules: recursive
+        path: jaeger-idl
+
+    - name: Build Proto in jaeger-idl
+      if: github.event_name == 'pull_request'
+      working-directory: jaeger-idl
+      run: make proto PROTOC_IMAGE=protobuf