iOS status-go builds failing with C compiler not found

[jakubgs]

We've been seeing seemingly random failures of iOS status-go builds with error like this:

# runtime/cgo
cgo: C compiler "2022-09-07" not found: exec: "2022-09-07": executable file not found in $PATH

Except the date that cgo thinks is a C compiler is the current date. This issue is known:

• x/mobile: Unable to build xcframework with gomobile and Xcode 14 golang/go#53316

Which is caused by xcrun printing weird and unexpected warnings to stdout on first use after reboot:

Last login: Wed Sep  7 09:14:57 2022 from 12.34.56.67
 % xcrun --find clang
2022-09-07 14:50:13.907 xcodebuild[69942:386823822] Requested but did not find extension point with identifier Xcode.IDEKit.ExtensionSentinelHostApplications for extension Xcode.DebuggerFoundation.AppExtensionHosts.watchOS of plug-in com.apple.dt.IDEWatchSupportCore
2022-09-07 14:50:13.908 xcodebuild[69942:386823822] Requested but did not find extension point with identifier Xcode.IDEKit.ExtensionPointIdentifierToBundleIdentifier for extension Xcode.DebuggerFoundation.AppExtensionToBundleIdentifierMap.watchOS of plug-in com.apple.dt.IDEWatchSupportCore
2022-09-07 14:50:14.041 xcodebuild[69942:386823822] XType: com.apple.fonts is not accessible.
2022-09-07 14:50:14.041 xcodebuild[69942:386823822] XType: XTFontStaticRegistry is enabled.
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang

 % xcrun --find clang
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang

 % xcrun --find clang
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang

This issue has been present with Command Line Tools 13.3.1 and 13.4.

[jakubgs]

I tried the MacOS upgrade, Command Line Tools upgrade and Xcode upgrade:

• https://github.com/status-im/infra-role-bootstrap-macos/commit/c0d02197 - cmdtools/xcode: upgrade from 13.3.1 to 13.4

But the warnings persist. Did it only on maci7-03 for now.

[jakubgs]

Some links about these errors:

• https://developer.apple.com/forums/thread/703233
• https://developer.apple.com/forums/thread/703823
• https://apple.stackexchange.com/questions/438785/xcode-error-when-launching-terminal
• https://fluttercorner.com/requested-but-did-not-find-extension-point-with-identifier/
• Requested but did not find extension point with identifier facebook/react-native#34063

It's possible the coming 14.0 Xcode release might fix this. And the RC1 came out today:
https://developer.apple.com/documentation/xcode-release-notes/xcode-14-release-notes

[jakubgs]

One possible option is to implement some validation in envClang():

func envClang(sdkName string) (clang, cflags string, err error) {
	if buildN {
		return sdkName + "-clang", "-isysroot " + sdkName, nil
	}
	cmd := exec.Command("xcrun", "--sdk", sdkName, "--find", "clang")
	out, err := cmd.CombinedOutput()
	if err != nil {
		return "", "", fmt.Errorf("xcrun --find: %v\n%s", err, out)
	}
	clang = strings.TrimSpace(string(out))

https://github.com/golang/mobile/blob/8578da9835fd365e78a6e63048c103b27a53a82c/cmd/gomobile/env.go#L434-L443

[jakubgs]

I created a PR which sanitizes xcrun output:

• cmd/gomobile: filter out xcrun warnings to get path golang/mobile#84

But they expect me to sign Google Contributor License Agreement(CLA), so I asked Agata to look into before I accept it.

[jakubgs]

Decided to apply the patch using Nix since it's quite simple, and will fix those failure while we wait for the PR to get merged.