Race with .intentionally-empty-file

[simonzkl]

There's a race condition when running multiple instances of cargo-zigbuild (when for example compiling to multiple targets at the same time)

Error: Failed to collect `zig cc` options
Caused by:
    Failed to run `zig cc -v` with status exit status: 1: clang version 19.1.7
    Target: x86_64-unknown-linux4.19.0-gnu2.31.0
    Thread model: posix
    InstalledDir: /nix/store/jb7n26fqzkbvqqwz0wm69gx0rm4cw9lg-zig-0.14.1/bin
    zig: error: no such file or directory: '/root/.cache/cargo-zigbuild/0.20.0/.intentionally-empty-file.c'

It can happen here:

cargo-zigbuild/src/zig.rs

Lines 686 to 688 in f903aaa

	if !empty_file_path.exists() {
	fs::write(&empty_file_path, "")?;
	}

Or potentially here?

cargo-zigbuild/src/zig.rs

Line 695 in f903aaa

fs::remove_file(&empty_file_path).ok();

I don't really understand why this is necessary, but I guess one easy way to fix this would be to randomly generate the file name.

[polarathene]

Possibly related to #318 ?

There is a PR since Feb waiting for review/feedback regarding that. Perhaps you could try it?

[simonzkl]

This is a different issue, but the same kind of bug (violating build isolation).