[WTF] Fix -Wc++23-lambda-attributes warnings by ddkilzer · Pull Request #52369 · WebKit/WebKit

ddkilzer · 2025-10-15T05:13:11Z

`1e73347`

[WTF] Fix -Wc++23-lambda-attributes warnings
<https://bugs.webkit.org/show_bug.cgi?id=300747>
<rdar://162639803>

Reviewed by Chris Dumez.

* Source/JavaScriptCore/Configurations/JavaScriptCore.xcconfig:
(MODULE_VERIFIER_SUPPORTED_LANGUAGE_STANDARDS): Add.
- Set variable based on the value of WK_HAS_VALID_JSC_PRIVATE_MODULE.
  This is similar to one of the changes in 301180@main for
  Source/WebKit/Configurations/WebKit.xcconfig.

Canonical link: https://commits.webkit.org/301598@main

a8aea76

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows	Apple Internal
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 win	✅ 🛠 ios-apple
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	~~🧪 wpe-wk2~~	~~🧪 win-tests~~	✅ 🛠 mac-apple
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 api-wpe		✅ 🛠 vision-apple
	~~🧪 ios-wk2-wpt~~	✅ 🧪 mac-wk1	✅ 🛠 wpe-cairo
✅ 🛠 🧪 jsc	~~🧪 api-ios~~	✅ 🧪 mac-wk2	✅ 🛠 gtk
✅ 🛠 🧪 jsc-arm64	✅ 🛠 vision	✅ 🧪 mac-AS-debug-wk2	~~🧪 gtk-wk2~~
	✅ 🛠 vision-sim	✅ 🧪 mac-wk2-stress	✅ 🧪 api-gtk
	✅ 🧪 vision-wk2	✅ 🧪 mac-intel-wk2	✅ 🛠 playstation
✅ 🛠 🧪 unsafe-merge	✅ 🛠 tv	✅ 🛠 mac-safer-cpp	✅ 🛠 jsc-armv7
	✅ 🛠 tv-sim		✅ 🧪 jsc-armv7-tests
	✅ 🛠 watch
	✅ 🛠 watch-sim

webkit-early-warning-system · 2025-10-15T05:13:19Z

EWS run on previous version of this PR (hash d969252)

Details

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows	Apple Internal
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 win	⏳ 🛠 ios-apple
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	✅ 🧪 wpe-wk2	✅ 🧪 win-tests	⏳ 🛠 mac-apple
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 api-wpe		⏳ 🛠 vision-apple
	✅ 🧪 ios-wk2-wpt	✅ 🧪 mac-wk1	✅ 🛠 wpe-cairo
✅ 🛠 🧪 jsc	✅ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🛠 gtk
✅ 🛠 🧪 jsc-arm64	✅ 🛠 vision	✅ 🧪 mac-AS-debug-wk2	❌ 🧪 gtk-wk2
	✅ 🛠 vision-sim	✅ 🧪 mac-wk2-stress	❌ 🧪 api-gtk
	✅ 🧪 vision-wk2	✅ 🧪 mac-intel-wk2	✅ 🛠 playstation
	✅ 🛠 tv	✅ 🛠 mac-safer-cpp	✅ 🛠 jsc-armv7
	✅ 🛠 tv-sim		✅ 🧪 jsc-armv7-tests
	✅ 🛠 watch
	✅ 🛠 watch-sim

ddkilzer · 2025-10-15T05:14:48Z

Source/WTF/wtf/Compiler.h

+#define IGNORE_CXX23_LAMBDA_ATTRIBUTES_BEGIN IGNORE_CLANG_WARNINGS_BEGIN("c++23-lambda-attributes")
+#define IGNORE_CXX23_LAMBDA_ATTRIBUTES_END IGNORE_CLANG_WARNINGS_END


Another way to fix this is to add -Wno-c++23-lambda-attributes to Configurations/CommonBase.xcconfig so we just ignore these warnings everywhere.

What I don't understand is that we're supposed to be building with -std=c++23 so why are we getting this warning in the first place? Did we fail to enable C++23 in some places?

oh I wonder if it’s because the WTF module map specifies a version < 23

/Applications/Xcode.app/Contents/Developer/Toolchains/OSX26.2.xctoolchain/usr/bin/clang -x c++ -fmessage-length\=0 -fdiagnostics-show-note-include-stack -fmacro-backtrace-limit\=0 -fno-color-diagnostics -fbuild-session-file\=/Users/cdumez/Library/Developer/Xcode/DerivedData/ModuleCache.noindex/Session.modulevalidation -fmodules-validate-once-per-build-session @/Volumes/Work/WebKit/OpenSource/WebKitBuild/JavaScriptCore.build/Debug/JavaScriptCore.build/VerifyModule/JavaScriptCore/c++-gnu++20-arm64e-apple-macos26.2-none/fe7502429db486ee15814c0d75f1b9fd-common-args.resp -MMD -MT dependencies -MF /Volumes/Work/WebKit/OpenSource/WebKitBuild/JavaScriptCore.build/Debug/JavaScriptCore.build/VerifyModule/JavaScriptCore/c++-gnu++20-arm64e-apple-macos26.2-none/Test.d --serialize-diagnostics /Volumes/Work/WebKit/OpenSource/WebKitBuild/JavaScriptCore.build/Debug/JavaScriptCore.build/VerifyModule/JavaScriptCore/c++-gnu++20-arm64e-apple-macos26.2-none/Test.dia -c /Volumes/Work/WebKit/OpenSource/WebKitBuild/JavaScriptCore.build/Debug/JavaScriptCore.build/VerifyModule/JavaScriptCore/c++/Test.cpp -o /Volumes/Work/WebKit/OpenSource/WebKitBuild/JavaScriptCore.build/Debug/JavaScriptCore.build/VerifyModule/JavaScriptCore/c++-gnu++20-arm64e-apple-macos26.2-none/Test.o

Given the c++-gnu++20 in the line, I suspect we forgot to turn on C++23 for some test project in JSC? Maybe we can fix that instead?

rr-codes · 2025-10-15T06:10:50Z

are we not able to just change WTF to use c++2b / c++23 instead?

cdumez · 2025-10-15T06:24:35Z

are we not able to just change WTF to use c++2b / c++23 instead?

My understanding was that c++2b and c++23 turn on the same features. My suspicion is that there is a project still building with c++20 in our codebase (In JSC land) that generates these warnings.

cdumez · 2025-10-15T06:36:36Z

JavaScriptCore VerifyModuleC /Volumes/Work/WebKit/OpenSource/WebKitBuild/Debug/JavaScriptCore.framework "" "" arm64e c++ gnu++20 "" com.apple.compilers.llvm.clang.1_0.verify_module

rr-codes · 2025-10-15T06:37:36Z

JavaScriptCore VerifyModuleC /Volumes/Work/WebKit/OpenSource/WebKitBuild/Debug/JavaScriptCore.framework "" "" arm64e c++ gnu++20 "" com.apple.compilers.llvm.clang.1_0.verify_module

oh, my suspicion was very close #52369 (comment)

ddkilzer · 2025-10-15T20:22:33Z

Okay, looking at fixing the module verification now.

webkit-early-warning-system · 2025-10-15T20:50:27Z

EWS run on previous version of this PR (hash 1c144ce)

Details

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows	Apple Internal
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	⏳ 🛠 wpe	⏳ 🛠 win	✅ 🛠 ios-apple
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	⏳ 🧪 wpe-wk2	⏳ 🧪 win-tests	✅ 🛠 mac-apple
✅ 🧪 webkitperl	~~🧪 ios-wk2~~	✅ 🧪 api-mac	⏳ 🧪 api-wpe		🛠 vision-apple
	~~🧪 ios-wk2-wpt~~	✅ 🧪 mac-wk1	✅ 🛠 wpe-cairo
✅ 🛠 🧪 jsc	⏳ 🧪 api-ios	✅ 🧪 mac-wk2	✅ 🛠 gtk
✅ 🛠 🧪 jsc-arm64	✅ 🛠 vision	✅ 🧪 mac-AS-debug-wk2	⏳ 🧪 gtk-wk2
	✅ 🛠 vision-sim	✅ 🧪 mac-wk2-stress	✅ 🧪 api-gtk
	✅ 🧪 vision-wk2	✅ 🧪 mac-intel-wk2	✅ 🛠 playstation
	✅ 🛠 tv	✅ 🛠 mac-safer-cpp	✅ 🛠 jsc-armv7
	✅ 🛠 tv-sim		✅ 🧪 jsc-armv7-tests
	⏳ 🛠 watch
	✅ 🛠 watch-sim

rr-codes · 2025-10-15T20:53:39Z

Source/JavaScriptCore/Configurations/JavaScriptCore.xcconfig

 MODULE_VERIFIER_SUPPORTED_LANGUAGES_YES = objective-c++ c++;

+MODULE_VERIFIER_SUPPORTED_LANGUAGE_STANDARDS = $(MODULE_VERIFIER_SUPPORTED_LANGUAGE_STANDARDS_$(WK_HAS_VALID_JSC_PRIVATE_MODULE));
+MODULE_VERIFIER_SUPPORTED_LANGUAGE_STANDARDS_ = gnu17;


the gnu17 isnt doing much on these 3 lines since ObjC verification is disabled in JSC for the time being

Okay, so what do you recommend setting? No value? I was cribbing values from 301180@main.

I'm trying to help here, but I'm outside my area of expertise. (Assume I know next to nothing about modules.)

ya I think no value for the _ and NO cases, and just gnu++whatever for the YES value

just gnu++whatever for the YES value

Any ideas how can I find out the default? Oh, maybe the aforementioned gnu++20?

the value should be whatever the project uses, which in our case is gnu++23 (I think? or c++23, I forget the difference)

It's this from Source/JavaScriptCore/Configurations/Base.xcconfig:

CLANG_CXX_LANGUAGE_STANDARD = c++2b;

Welp, not that:

Source/JavaScriptCore/JavaScriptCore.xcodeproj: warning: Unsupported module verifier language standard "c++2b" (in target 'JavaScriptCore' from project 'JavaScriptCore')

Seems like I need to use just c++23.

webkit-early-warning-system · 2025-10-15T23:30:32Z

EWS run on current version of this PR (hash a8aea76)

Details

Misc	iOS, visionOS, tvOS & watchOS	macOS	Linux	Windows	Apple Internal
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 win	✅ 🛠 ios-apple
	✅ 🛠 ios-sim	✅ 🛠 mac-AS-debug	~~🧪 wpe-wk2~~	~~🧪 win-tests~~	✅ 🛠 mac-apple
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🧪 api-mac	✅ 🧪 api-wpe		✅ 🛠 vision-apple
	~~🧪 ios-wk2-wpt~~	✅ 🧪 mac-wk1	✅ 🛠 wpe-cairo
✅ 🛠 🧪 jsc	~~🧪 api-ios~~	✅ 🧪 mac-wk2	✅ 🛠 gtk
✅ 🛠 🧪 jsc-arm64	✅ 🛠 vision	✅ 🧪 mac-AS-debug-wk2	~~🧪 gtk-wk2~~
	✅ 🛠 vision-sim	✅ 🧪 mac-wk2-stress	✅ 🧪 api-gtk
	✅ 🧪 vision-wk2	✅ 🧪 mac-intel-wk2	✅ 🛠 playstation
✅ 🛠 🧪 unsafe-merge	✅ 🛠 tv	✅ 🛠 mac-safer-cpp	✅ 🛠 jsc-armv7
	✅ 🛠 tv-sim		✅ 🧪 jsc-armv7-tests
	✅ 🛠 watch
	✅ 🛠 watch-sim

<https://bugs.webkit.org/show_bug.cgi?id=300747> <rdar://162639803> Reviewed by Chris Dumez. * Source/JavaScriptCore/Configurations/JavaScriptCore.xcconfig: (MODULE_VERIFIER_SUPPORTED_LANGUAGE_STANDARDS): Add. - Set variable based on the value of WK_HAS_VALID_JSC_PRIVATE_MODULE. This is similar to one of the changes in 301180@main for Source/WebKit/Configurations/WebKit.xcconfig. Canonical link: https://commits.webkit.org/301598@main

webkit-commit-queue · 2025-10-16T02:56:01Z

Committed 301598@main (1e73347): https://commits.webkit.org/301598@main

Reviewed commits have been landed. Closing PR #52369 and removing active labels.

ddkilzer self-assigned this Oct 15, 2025

ddkilzer requested a review from cdumez October 15, 2025 05:13

ddkilzer commented Oct 15, 2025

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ddkilzer force-pushed the eng/WTF-Fix-Wc-23-lambda-attributes-warnings branch from d969252 to 1c144ce Compare October 15, 2025 20:50

ddkilzer requested a review from emw-apple as a code owner October 15, 2025 20:50

rr-codes reviewed Oct 15, 2025

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ddkilzer requested a review from rr-codes October 15, 2025 21:04

ddkilzer force-pushed the eng/WTF-Fix-Wc-23-lambda-attributes-warnings branch from 1c144ce to a8aea76 Compare October 15, 2025 23:30

cdumez approved these changes Oct 15, 2025

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ddkilzer added the unsafe-merge-queue Applied to send a pull request to merge-queue, but skip building and testing label Oct 16, 2025

webkit-commit-queue force-pushed the eng/WTF-Fix-Wc-23-lambda-attributes-warnings branch from a8aea76 to 1e73347 Compare October 16, 2025 02:55

webkit-commit-queue merged commit 1e73347 into WebKit:main Oct 16, 2025

webkit-commit-queue removed the unsafe-merge-queue Applied to send a pull request to merge-queue, but skip building and testing label Oct 16, 2025

ddkilzer deleted the eng/WTF-Fix-Wc-23-lambda-attributes-warnings branch October 16, 2025 02:56

ddkilzer added the JavaScriptCore For bugs in JavaScriptCore, the JS engine used by WebKit, other than kxmlcore issues. label Oct 16, 2025

		#define IGNORE_CXX23_LAMBDA_ATTRIBUTES_BEGIN IGNORE_CLANG_WARNINGS_BEGIN("c++23-lambda-attributes")
		#define IGNORE_CXX23_LAMBDA_ATTRIBUTES_END IGNORE_CLANG_WARNINGS_END

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