sys::thread_local::key::tests::destructors fails under x86 Windows 7

[PaulDance]

Code

Running the sys::thread_local::key::tests::destructors test under x86 Windows 7 (i686-win7-windows-msvc) currently fails with the following error:

thread 'sys::thread_local::key::tests::destructors' panicked at library/std/src/sys/thread_local/key/tests.rs:57:5:
assertion `left == right` failed: destructor should have dropped the other reference on thread exit
  left: 2
 right: 1

Version it worked on

The test does not fail when using dev @ 3c5aef3, or a7c39b6 if only considering first-parent master merge commits.

Version with regression

It starts to fail with the following 67a97ba commit of the same 077cedc rollup. It still fails more recently with 2b96ddc.

This is therefore definitely caused by #140007. That makes sense considering there hasn't been much other changes to the target recently. However, it is concerning because the target should still have emulated TLS, as intended by the PR "at fault". There could thus be a problem with the TLS emulation itself.

@rustbot label A-atomic A-thread-locals A-destructors A-testsuite O-x86_32 O-windows-7 O-windows-msvc

@rustbot modify labels: +regression-from-stable-to-beta -regression-untriaged

[jieyouxu]

FYI @roblabla

[PaulDance]

@jieyouxu good accuracy on that blind shot 😄

[jieyouxu]

@jieyouxu good accuracy on that blind shot 😄

(It's not a blindshot, they're the target maintainer of i686-win7-windows-msvc, and it was a heads-up for their information.)

[PaulDance]

It's not a blindshot

Yes yes, I know, sorry. I just found it a little funny that it landed on the most precise ping possible in the end considering the changes at fault, but right from the very start 😉

[PaulDance]

By the way, we're working at the same company and in the same team, so I can already confirm the issue has been noted. We'll continue on investigating it in order to try finding a more specific cause and a potential proper fix.

[jieyouxu]

Assigning P-low as per discussion.

@rustbot label: -I-prioritize +P-low