Spurious JSON parsing failure on bots #33390
Description
http://buildbot.rust-lang.org/builders/auto-win-gnu-32-nopt-t/builds/4079/steps/test/logs/stdio
https://gist.github.com/alexcrichton/997dd9cae99b934f945a01082d99313b
#33376 (comment)
failures:
---- [compile-fail] compile-fail\dep-graph-struct-signature.rs stdout ----
thread '[compile-fail] compile-fail\dep-graph-struct-signature.rs' panicked at 'failed to decode compiler output as json: `ParseError(SyntaxError(ExpectedColon, 1, 11))`', C:/bot/slave/auto-win-gnu-32-nopt-t/build/src/tools/compiletest/src\json.rs:75
note: Run with `RUST_BACKTRACE=1` for a backtrace.
failures:
[compile-fail] compile-fail\dep-graph-struct-signature.rs
test result: FAILED. 2205 passed; 1 failed; 11 ignored; 0 measured
I've seen this a few times at this point, not really sure what's going on.
cc @nikomatsakis, @jonathandturner -- the failure message here is unfortunately hiding lots of information like what happened to the underlying process, can we try and surface that?