1.53.0 test join_orders_after_tls_destructors fails on armhf (armv7-unknown-linux-gnueabihf) Debian

[infinity0]

From the build log (warning several MB):

failures:

---- thread::local::tests::join_orders_after_tls_destructors stdout ----
thread 'thread::local::tests::join_orders_after_tls_destructors' panicked at 'internal error: entered unreachable code: sync state: Err(2)', library/std/src/thread/local/tests.rs:312:22
stack backtrace:
   0: rust_begin_unwind
             at /usr/src/rustc-1.53.0/library/std/src/panicking.rs:493:5
   1: core::panicking::panic_fmt
             at /usr/src/rustc-1.53.0/library/core/src/panicking.rs:92:14
   2: std::thread::local::tests::join_orders_after_tls_destructors
   3: core::ops::function::FnOnce::call_once
             at /usr/src/rustc-1.53.0/library/core/src/ops/function.rs:227:5
note: Some details are omitted, run with `RUST_BACKTRACE=full` for a verbose backtrace.

CC @mzohreva who added the test in #84409

[jethrogb]

This was fixed in #86383 which landed in 1.55.0

[infinity0]

Thanks, I will backport it into 1.53.0 on Debian.

[infinity0]

The patch breaks self-bootstrapping on 1.53 (using 1.53 as the bootstrap compiler to build 1.53) as it relies on the later lang item slice_len_fn; I will revert it and ignore this test failure temporarily on armhf until 1.54.

[jethrogb]

You should only patch the test, not any of the other files touched by that PR.

[infinity0]

So just this?

--- a/library/std/src/thread/local/tests.rs
+++ b/library/std/src/thread/local/tests.rs
@@ -297,7 +297,7 @@
             .unwrap();
 
         loop {
-            match SYNC_STATE.compare_exchange_weak(
+            match SYNC_STATE.compare_exchange(
                 THREAD1_WAITING,
                 MAIN_THREAD_RENDEZVOUS,
                 Ordering::SeqCst,

I am actually confused about our bootstrapping failures; it looks like slice_len_fn is defined wholely within that PR, so backporting it onto 1.53 should be fine? But we get:

error[E0522]: definition of an unknown language item: `slice_len_fn`
  --> library/core/src/slice/mod.rs:99:32
   |
99 |     #[cfg_attr(not(bootstrap), lang = "slice_len_fn")]
   |                                ^^^^^^^^^^^^^^^^^^^^^ definition of unknown language item `slice_len_fn`

     Running `/<<PKGBUILDDIR>>/build/x86_64-unknown-linux-gnu/stage0-std/release/build/unwind-216b748a34c54be2/build-script-build`

That is, not(bootstrap) seems to be true even though we are building stage0-std.

[infinity0]

Ah, ok nvmd I think it's because src/bootstrap/builder.rs detects we're running the "same" version, so explicitly does not set --cfg=bootstrap, but the "same" version actually does not have that lang item.

[infinity0]

Closing as it's already fixed.