build(mocks): Generate mocks with the pinned mockgen and check them in CI

.github/workflows/ci.yml

@@ -47,7 +47,7 @@ jobs:
         run: make lint
 
   # ---------------------------------------------------------------------------
-  # TIDY (module files + BUILD files in sync)
+  # TIDY (module files + BUILD files + mocks in sync)
   # ---------------------------------------------------------------------------
   tidy:
     name: Tidy
@@ -67,6 +67,9 @@ jobs:
       - name: Check BUILD files are up to date
         run: make check-gazelle
 
+      - name: Check mocks are up to date
+        run: make check-mocks
+
   # ---------------------------------------------------------------------------
   # BUILD AND UNIT TESTS (parallel jobs, separate Bazel caches)
   # ---------------------------------------------------------------------------

Makefile

@@ -631,9 +631,12 @@ GO_GENERATE_PACKAGES := \
 	./submitqueue/gateway/extension/storage/... \
 	./submitqueue/orchestrator/extension/storage/...
 
-mocks: ## Generate mock files using mockgen
+mocks: ## Generate mock files using the pinned mockgen
 	@echo "Generating mocks..."
-	@$(BAZEL) run @rules_go//go -- generate $(GO_GENERATE_PACKAGES)
+	@$(BAZEL) build @org_uber_go_mock//mockgen
+	@mkdir -p bin/mockgen
+	@cp -f "$$($(BAZEL) cquery --output=files @org_uber_go_mock//mockgen 2>/dev/null)" bin/mockgen/mockgen
+	@PATH="$(CURDIR)/bin/mockgen:$$PATH" $(BAZEL) run @rules_go//go -- generate $(GO_GENERATE_PACKAGES)
 	@echo "Mocks generated successfully!"
 
 proto: ## Generate protobuf files from .proto definitions

doc/howto/DEVELOPMENT.md

@@ -92,7 +92,7 @@ brew install grpcurl
 
 `make help` lists every target. The table below is the day-to-day set.
 
-CI runs `make lint`, `make check-tidy`, and `make check-gazelle`. `make lint` includes the format check, license headers, the tracked-binary check, the message-ID check, and the queue-shard check. `make fmt`, `make tidy`, and `make gazelle` apply the corresponding fixes. `make mocks` regenerates the checked-in mockgen files; `make check-mocks` fails when that output differs from the tree. `make clean` removes the Bazel cache and `bin/`. Generated protobuf Go files stay in the source tree until `make clean-proto`; `make proto` writes them again.
+CI runs `make lint`, `make check-tidy`, `make check-gazelle`, and `make check-mocks`. `make lint` includes the format check, license headers, the tracked-binary check, the message-ID check, and the queue-shard check. `make fmt`, `make tidy`, and `make gazelle` apply the corresponding fixes. `make mocks` regenerates the checked-in mockgen files with the `mockgen` pinned in `go.mod`, which Bazel builds into `bin/mockgen/` and puts first on `PATH`, so no local install is needed and a different `mockgen` on your `PATH` is ignored; run `go generate` directly only with that binary on `PATH`. `make check-mocks` fails when that output differs from the tree. `make clean` removes the Bazel cache and `bin/`. Generated protobuf Go files stay in the source tree until `make clean-proto`; `make proto` writes them again.
 
 | Target | Description |
 |--------|-------------|