tests/common/util.rs panics with Broken pipe error on some targets when pipe_in() is used in tests

[zhitkoff]

coreutils/tests/common/util.rs

Lines 2014 to 2015 in aa0437c

	.expect("Error joining with the piping stdin thread")
	.unwrap();

This seems to be the culprit. Maybe add handling the errors with match/if let instead of expect().unwrap() ?

[tertsdiepraam]

Hmm, what would we then do in the error branch? I guess we could ignore the error, but that shouldn't be necessary. Which targets are impacted by this?

[zhitkoff]

yes, specifically for broken pipe - ignore it. Panic on the other errors. Targets where it failed consistently are ubuntu-latest intel (i686, x84_64). All other targets did not fail on the same tests. The workaround is to use .ignore_stdin_write_error() of UCommand instances in tests that use .pipe_in() stdin feed, but it should not be required - it works without it on all other targets.

Example: https:/uutils/coreutils/actions/runs/6342269393/job/17227755302