cmd/go: ld: building for macOS, but linking in object file built for iOS

[bradfitz]

Go 1.19.4

When building our application, a few of us occasionally get the error:

/Users/bradfitz/.cache/tailscale-go/pkg/tool/darwin_arm64/link: running gcc failed: exit status 1
ld: building for macOS, but linking in object file built for iOS, file '/var/folders/0f/7sz95dc94nj46b6yz8p_fqd40000gn/T/go-link-3835913802/000004.o' for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

And the only way to recover is to do a go clean -cache and build again.

We haven't figured out more than that, yet. And we don't have an on-demand repro.

Just filing this now in case anybody has any ideas.

Like, maybe piece of the environment is missing from the cache signature? Maybe an empty file is being created that's being interpreted as iOS instead of macOS?

But that error message is not a Go thing at all. I see tons of Google results for other languages. But maybe cmd/go can detect whatever broken state its input is in and ignore that input file and rebuild it instead? Totally guessing.

/cc @ianlancetaylor who likes linkers :)

[spatialbits]

Ran into this on Friday after upgrading from 1.19.1 to 1.19.4.

[ianlancetaylor]

It sounds like once this problem occurs, it is repeatable. If so, then when it happens again, run with -ldflags=-tmpdir=/my/private/tmpdir and take a look at the failing file.