Enable -Weverything warnings and add optional active_message field

.bazelrc

@@ -30,6 +30,11 @@ test:valgrind --run_under='valgrind --leak-check=full --show-leak-kinds=definite
 
 build --enable_platform_specific_config
 
+# Treat third-party (external repo) headers as system headers so the aggressive
+# 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
+
 # For all builds, use C++17
 build --cxxopt="-std=c++17"
 build --cxxopt='-Wno-sign-compare'

.clang-format

@@ -0,0 +1 @@
+BasedOnStyle: Google

MODULE.bazel

@@ -1,6 +1,6 @@
 module(
     name = "phaser",
-    version = "1.1.0"
+    version = "1.1.1"
 )
 
 bazel_dep(name = "bazel_skylib", version = "1.9.0")

phaser/BUILD.bazel

@@ -5,6 +5,13 @@ package(default_visibility = ["//visibility:public"])
 
 exports_files(["valgrind.supp"])
 
+# True when building with clang, which gates the clang-only -Weverything set in
+# PHASER_COPTS (GCC does not understand -Weverything).
+config_setting(
+    name = "is_clang",
+    flag_values = {"@bazel_tools//tools/cpp:compiler": "clang"},
+)
+
 cc_library(
     name = "test_helpers",
     hdrs = ["test_helpers.h"],
@@ -31,6 +38,18 @@ cc_test(
     ],
 )
 
+cc_test(
+    name = "active_message_test",
+    srcs = ["active_message_test.cc"],
+    copts = PHASER_COPTS,
+    data = ["valgrind.supp"],
+    deps = [
+        "//phaser/runtime:phaser_runtime",
+        "//phaser/testdata:foo_active_message_phaser",
+        "@com_google_googletest//:gtest",
+    ],
+)
+
 cc_test(
     name = "all_types_test",
     srcs = ["all_types_test.cc"],

phaser/active_message_test.cc

@@ -0,0 +1,45 @@
+// Copyright 2024-2026 David Allison
+// All Rights Reserved
+// See LICENSE file for licensing information.
+
+#include <gtest/gtest.h>
+
+#include <any>
+#include <string>
+
+#include "phaser/runtime/runtime.h"
+#include "phaser/testdata/Foo.phaser.h"
+
+// Verifies the optional `std::any active_message` field that is emitted when a
+// phaser_library is built with enable_active_message = True (which passes the
+// active_message=true plugin command-line option).
+TEST(ActiveMessage, DefaultsToEmpty) {
+  char* buffer = static_cast<char*>(calloc(4096, 1));
+  foo::bar::phaser::Foo msg =
+      foo::bar::phaser::Foo::CreateMutable(buffer, 4096);
+  EXPECT_FALSE(msg.active_message.has_value());
+  free(buffer);
+}
+
+TEST(ActiveMessage, HoldsArbitraryPayload) {
+  char* buffer = static_cast<char*>(calloc(4096, 1));
+  foo::bar::phaser::Foo msg =
+      foo::bar::phaser::Foo::CreateMutable(buffer, 4096);
+
+  // The field is a public std::any, independent of the wire-format fields.
+  msg.set_a(42);
+  msg.active_message = std::string("attached-payload");
+
+  ASSERT_TRUE(msg.active_message.has_value());
+  EXPECT_EQ("attached-payload", std::any_cast<std::string>(msg.active_message));
+  EXPECT_EQ(42, msg.a());
+
+  msg.active_message.reset();
+  EXPECT_FALSE(msg.active_message.has_value());
+  free(buffer);
+}
+
+int main(int argc, char** argv) {
+  testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}