Intermittent with backtrace-debuginfo.rs

[Manishearth]

http://buildbot.rust-lang.org/builders/auto-linux-32-opt/builds/6036/steps/test/logs/stdio from #27617

failures:

---- [run-pass] run-pass/backtrace-debuginfo.rs stdout ----

error: test run failed!
status: exit code: 101
command: i686-unknown-linux-gnu/test/run-pass/backtrace-debuginfo.stage2-i686-unknown-linux-gnu 
stdout:
------------------------------------------

------------------------------------------
stderr:
------------------------------------------
thread '<main>' panicked at 'trace does not match position list: test case 3
thread '<main>' panicked at 'explicit panic', /home/ubuntu/src/rust-buildbot/slave/auto-linux-32-opt/build/src/test/run-pass/backtrace-debuginfo.rs:79
stack backtrace:
   1: 0x55640dc0 - sys::backtrace::write::h24f1716ef3fafcd37As
   2: 0x5564a225 - panicking::on_panic::h5c416bec33d18845IFx
   3: 0x556065b1 - rt::unwind::begin_unwind_inner::he563e4ed74b0a915T6w
   4: 0x55556e6c - rt::unwind::begin_unwind::h11536406982305423188
                at ../src/libstd/rt/unwind/mod.rs:236
   5: 0x55556dfe - inner::hebc4c6975bd94e72uca
                at /home/ubuntu/src/rust-buildbot/slave/auto-linux-32-opt/build/obj/<std macros>:3
   6: 0x555570bd - outer::h56df4a17ad3d0ec6kla
                at /home/ubuntu/src/rust-buildbot/slave/auto-linux-32-opt/build/src/test/run-pass/backtrace-debuginfo.rs:104
   7: 0x55559a56 - main::hfba55d59fb2cc519Pqa
                at /home/ubuntu/src/rust-buildbot/slave/auto-linux-32-opt/build/src/test/run-pass/backtrace-debuginfo.rs:152
   8: 0x5564c2ea - rt::unwind::try::try_fn::h13372541063495895142
   9: 0x55649a6d - __rust_try
  10: 0x5564bfee - rt::lang_start::h1d090ba3935217b6DAx
  11: 0x5555a512 - main
  12: 0x559b5a82 - __libc_start_main
  13: 0x55556850 - <unknown>

---
backtrace-debuginfo-aux.rs:20
backtrace-debuginfo.rs:78
backtrace-debuginfo.rs:104
backtrace-debuginfo.rs:152
', /home/ubuntu/src/rust-buildbot/slave/auto-linux-32-opt/build/src/test/run-pass/backtrace-debuginfo.rs:118

------------------------------------------

thread '[run-pass] run-pass/backtrace-debuginfo.rs' panicked at 'explicit panic', /home/ubuntu/src/rust-buildbot/slave/auto-linux-32-opt/build/src/compiletest/runtest.rs:1490



failures:
    [run-pass] run-pass/backtrace-debuginfo.rs

[TimNN]

I think this needs to be reopened:

cc #27617, #27612, #27611

[TimNN]

I just tried building the master branch locally and it fails with the same error (compiling i686-unknown-linux-gnu on 64bit ubuntu).

[TimNN]

Looks like this was introduced in febdc3b (a5d33d8 tests successfully for me) when @arielb1 accidentally pushed to master (see https://botbot.me/mozilla/rust-internals/2015-08-09/?msg=46787325&page=2; because of the minor change the consensus was to leave the commit as is).

[bluss]

I'm sorry that I didn't suggest more caution there, truly surprising breakage. Lesson learned.. everything must pass bors.

[barosl]

That's quite intriguing! The one-line change seemed truly innocent to me. Any idea on how the breakage happened?

[alexcrichton]

Fixed in #27634