Centralize Shardok C++ standard settings (#8197)

.bazelrc

@@ -14,6 +14,7 @@ common --worker_sandboxing
 common --local_test_jobs=64
 common --jobs=64
 
+# Keep these C++ standard flags in sync with tools/copts.bzl and scripts/shardok_cpp_config.sh.
 common --cxxopt="--std=c++23"
 common --cxxopt="-Wno-deprecated-non-prototype"
 common --per_file_copt=src/test/cpp/.*@-Wno-character-conversion

scripts/check_shardok_clang_tidy.sh

@@ -7,6 +7,7 @@
 set -euo pipefail
 
 repo_root="$(git rev-parse --show-toplevel)"
+source "$repo_root/scripts/shardok_cpp_config.sh"
 
 files=(
     "src/main/cpp/net/eagle0/shardok/library/ActionCost.hpp"
@@ -15,7 +16,7 @@ files=(
 
 compiler_args=(
     "-I$repo_root"
-    "-std=c++23"
+    "$SHARDOK_CXX_STANDARD_ARG"
 )
 
 if command -v xcrun >/dev/null 2>&1; then

scripts/run-clang-tidy.sh

@@ -10,13 +10,14 @@ set -e
 export PATH="/opt/homebrew/bin:/usr/local/bin:$PATH"
 
 repo_root="$(git rev-parse --show-toplevel)"
+source "$repo_root/scripts/shardok_cpp_config.sh"
 
 if [ "$#" -eq 0 ]; then
     echo "Usage: scripts/run-clang-tidy.sh [clang-tidy args] <files> [-- <compiler args>]"
     echo ""
     echo "Examples:"
     echo "  scripts/run-clang-tidy.sh --verify-config"
-    echo "  scripts/run-clang-tidy.sh src/main/cpp/net/eagle0/shardok/library/CombatDamage.hpp -- -I$repo_root -std=c++23"
+    echo "  scripts/run-clang-tidy.sh src/main/cpp/net/eagle0/shardok/library/CombatDamage.hpp -- -I$repo_root $SHARDOK_CXX_STANDARD_ARG"
     exit 2
 fi
 

scripts/shardok_cpp_config.sh

@@ -0,0 +1,5 @@
+#!/bin/bash
+# Shared C++ settings for shell scripts that invoke Shardok tooling outside Bazel.
+
+SHARDOK_CXX_STANDARD="c++23"
+SHARDOK_CXX_STANDARD_ARG="-std=${SHARDOK_CXX_STANDARD}"

tools/copts.bzl

@@ -1,4 +1,14 @@
 # Suppress -Wdeprecated-copy-with-dtor after -Wdeprecated due to protobuf 32.x warning
-COPTS = ["--std=c++23", "-Werror", "-Wall", "-Wextra", "-Wdeprecated", "-Wno-deprecated-copy-with-dtor"]
+CXX_STANDARD = "c++23"
+CXX_STANDARD_COPT = "--std=" + CXX_STANDARD
+
+COPTS = [
+    CXX_STANDARD_COPT,
+    "-Werror",
+    "-Wall",
+    "-Wextra",
+    "-Wdeprecated",
+    "-Wno-deprecated-copy-with-dtor",
+]
 
 TEST_COPTS = COPTS + ["-Iexternal/gtest/include"]