Add logic to skip generation if protoc is missing or not the version we want

Helpful for local development

Author: matthewmcneely

pb/gen.sh

@@ -1,7 +1,24 @@
 #!/bin/bash
 
 # Run this script from its directory, so that badgerpb4.proto is where it's expected to
-# be.
+# be. Only run this script if you've made changes to the API in badgerpb4.proto.
+
+# Check if protoc version matches expected version first
+EXPECTED_PROTOC_VERSION="3.21.12"
+ACTUAL_PROTOC_VERSION=$(protoc --version 2>/dev/null | grep -o '[0-9]\+\.[0-9]\+\.[0-9]\+')
+
+if [[ ${ACTUAL_PROTOC_VERSION} != "${EXPECTED_PROTOC_VERSION}" ]]; then
+	echo "Warning: protoc version mismatch"
+	echo "Expected: ${EXPECTED_PROTOC_VERSION}"
+	echo "Actual: ${ACTUAL_PROTOC_VERSION:-'not found'}"
+	echo "Skipping generation"
+	exit 0
+fi
 
 go install google.golang.org/protobuf/cmd/protoc-gen-go@v1.31.0
+
+# Get the GOPATH and add the bin directory to PATH
+GOPATH=$(go env GOPATH)
+export PATH="${GOPATH}/bin:${PATH}"
+
 protoc --go_out=. --go_opt=paths=source_relative badgerpb4.proto