Improve ROS compatibility and clean compiler warnings

.bazelrc

@@ -50,6 +50,10 @@ build --enable_platform_specific_config
 # warning set used for our own code (see phaser/copts.bzl) does not flood the
 # build with diagnostics from abseil/protobuf/googletest/toolbelt.
 build --features=external_include_paths
+# Dependency sources are outside Phaser's control. Keep clean builds focused on
+# diagnostics actionable in this repository for both target and tool builds.
+build --per_file_copt=^external/.*@-w
+build --host_per_file_copt=^external/.*@-w
 
 # For all builds, use C++17
 build --cxxopt="-std=c++17"

phaser/BUILD.bazel

@@ -1,7 +1,11 @@
 load("@com_google_protobuf//bazel:cc_proto_library.bzl", "cc_proto_library")
 load("@com_google_protobuf//bazel:proto_library.bzl", "proto_library")
 load("@rules_cc//cc:defs.bzl", "cc_binary", "cc_library", "cc_test")
-load("//phaser:copts.bzl", "PHASER_COPTS")
+load(
+    "//phaser:copts.bzl",
+    "PHASER_COPTS",
+    "PHASER_PROTOBUF_GENERATED_COPTS",
+)
 
 package(default_visibility = ["//visibility:public"])
 
@@ -38,7 +42,7 @@ cc_test(
     srcs = [
         "phaser_test.cc",
     ],
-    copts = PHASER_COPTS,
+    copts = PHASER_COPTS + PHASER_PROTOBUF_GENERATED_COPTS,
     data = ["valgrind.supp"],
     deps = [
         ":test_helpers",
@@ -66,12 +70,13 @@ cc_test(
 cc_test(
     name = "ros_compile_test",
     srcs = ["ros_compile_test.cc"],
-    copts = PHASER_COPTS,
+    copts = PHASER_COPTS + PHASER_PROTOBUF_GENERATED_COPTS,
     data = ["valgrind.supp"],
     deps = [
         "//phaser/runtime:phaser_runtime",
         "//phaser/testdata:ros_compile_cc_proto",
         "//phaser/testdata:ros_compile_phaser",
+        "//phaser/testdata:service_only_phaser",
         "@com_google_absl//absl/types:span",
         "@com_google_googletest//:gtest_main",
     ],
@@ -192,7 +197,7 @@ cc_test(
 cc_test(
     name = "ros_wire_conversion_test",
     srcs = ["ros_wire_conversion_test.cc"],
-    copts = PHASER_COPTS,
+    copts = PHASER_COPTS + PHASER_PROTOBUF_GENERATED_COPTS,
     data = ["valgrind.supp"],
     deps = [
         "//phaser/runtime:phaser_runtime",
@@ -208,7 +213,7 @@ cc_test(
 cc_test(
     name = "all_types_test",
     srcs = ["all_types_test.cc"],
-    copts = PHASER_COPTS,
+    copts = PHASER_COPTS + PHASER_PROTOBUF_GENERATED_COPTS,
     data = ["valgrind.supp"],
     deps = [
         ":test_helpers",
@@ -246,7 +251,7 @@ cc_test(
     # Performance benchmark; excluded from wildcard test runs (e.g. //...).
     # Run explicitly with `bazel test //phaser:perf_test`.
     tags = ["manual"],
-    copts = PHASER_COPTS,
+    copts = PHASER_COPTS + PHASER_PROTOBUF_GENERATED_COPTS,
     deps = [
         "//phaser/runtime:phaser_runtime",
         "//phaser/testdata:test_message_phaser",

phaser/compiler/BUILD.bazel

@@ -1,5 +1,5 @@
 load("@rules_cc//cc:defs.bzl", "cc_binary", "cc_library")
-load("//phaser:copts.bzl", "PHASER_COPTS")
+load("//phaser:copts.bzl", "PHASER_PROTOC_COPTS")
 
 package(default_visibility = ["//visibility:public"])
 
@@ -10,7 +10,7 @@ cc_library(
         "gen.cc",
         "message_gen.cc",
     ],
-    copts = PHASER_COPTS,
+    copts = PHASER_PROTOC_COPTS,
     hdrs = [
         "enum_gen.h",
         "gen.h",
@@ -33,7 +33,7 @@ cc_binary(
     srcs = [
         "main.cc",
     ],
-    copts = PHASER_COPTS,
+    copts = PHASER_PROTOC_COPTS,
     deps = [
         ":phaser_lib",
         "@com_google_absl//absl/flags:flag",

phaser/compiler/gen.cc

@@ -152,14 +152,31 @@ bool CodeGenerator::Generate(
       generate_ros_metadata_ &&
       file->package().rfind("google.protobuf", 0) != 0;
 
-  // Custom option schemas and other message-free protos need no C++ output.
-  // descriptor.proto is imported for extensions but must not be emitted as a
-  // Phaser message graph (it is huge and not a runtime payload type here).
-  if (file->message_type_count() == 0 && file->enum_type_count() == 0) {
-    return true;
-  }
-  if (file->name() == std::string("google/protobuf/descriptor.proto") ||
+  // Custom option schemas, service-only files, and descriptor.proto need no
+  // generated declarations. Still create their declared outputs so build rules
+  // can safely include them in larger transitive proto graphs.
+  if ((file->message_type_count() == 0 && file->enum_type_count() == 0) ||
+      file->name() == std::string("google/protobuf/descriptor.proto") ||
       file->name() == std::string("phaser/options.proto")) {
+    std::string filename = GeneratedFilename(
+        package_name_, target_name_, std::string(file->name()));
+    std::filesystem::path hp(filename);
+    hp.replace_extension(".phaser.h");
+    std::filesystem::path cp(filename);
+    cp.replace_extension(".phaser.cc");
+    auto header_output = std::unique_ptr<google::protobuf::io::ZeroCopyOutputStream>(
+        generator_context->Open(hp.string()));
+    auto source_output = std::unique_ptr<google::protobuf::io::ZeroCopyOutputStream>(
+        generator_context->Open(cp.string()));
+    if (header_output == nullptr || source_output == nullptr) {
+      *error = absl::StrFormat("Failed to create empty outputs for %s",
+                               file->name());
+      return false;
+    }
+    WriteToZeroCopyStream("// No Phaser declarations in this schema.\n",
+                          header_output.get());
+    WriteToZeroCopyStream("// No Phaser definitions in this schema.\n",
+                          source_output.get());
     return true;
   }