313560 2026-04-28 11:37:45 -0700 [CMake] Set --std=c++17 for the libatomic probe 2026-04-29 01:41:21 -0700 1 1 1 Unclassified WebKit CMake WebKit Nightly Build Unspecified Unspecified RESOLVED FIXED InRadar P2 Normal --- 1 zakr aperez aperez webkit-bug-importer oldest_to_newest 2205430 0 zakr 2026-04-28 11:37:45 -0700 The atomic source test uses std::atomic<std::optional<double>>, which requires C++17. check_cxx_source_compiles inherits the compiler's default C++ standard, and on compilers that default to C++14 or earlier the probe fails with "no member named 'optional' in namespace 'std'". Pre-312202@main this was silent and the build proceeded (builtins suffice on arm64 without libatomic). 312202@main promoted the failure to FATAL_ERROR, which broke the CMake build on those compilers. Set CMAKE_REQUIRED_FLAGS to --std=c++2b around the probe, mirroring the existing pattern at the std::filesystem detection a few lines below. unset() restores the previous state. 2205431 1 webkit-bug-importer 2026-04-28 11:37:52 -0700 <rdar://problem/175777090> 2205434 2 zakr 2026-04-28 11:47:10 -0700 Pull request: https://github.com/WebKit/WebKit/pull/63816 2205450 3 ews-feeder 2026-04-28 13:11:58 -0700 Committed 312222@main (cfb69a99823a): <https://commits.webkit.org/312222@main> Reviewed commits have been landed. Closing PR #63816 and removing active labels. 2205479 4 aperez 2026-04-28 14:22:48 -0700 Reopening for a follow-up. 2205487 5 aperez 2026-04-28 14:32:01 -0700 Pull request: https://github.com/WebKit/WebKit/pull/63832 2205667 6 ews-feeder 2026-04-29 00:09:47 -0700 Committed 312266@main (07ed81f30130): <https://commits.webkit.org/312266@main> Reviewed commits have been landed. Closing PR #63832 and removing active labels. 2205688 7 ews-feeder 2026-04-29 01:41:21 -0700 Committed 305877.462@webkitglib/2.52 (b7eabfc1efa4): <https://commits.webkit.org/305877.462@webkitglib/2.52> Reviewed commits have been landed. Closing PR #63872 and removing active labels.