Spurious macOS 30-minute timeout when compiling stage0-rustc

[kennytm]

Symptom: The build failed within 1 hour. The macOS errored with an ❗️ on Travis. The log shows something like:

[00:51:06]    Compiling rustc_const_math v0.0.0 (file:///Users/travis/build/rust-lang/rust/src/librustc_const_math)
[00:51:06]    Compiling proc_macro v0.0.0 (file:///Users/travis/build/rust-lang/rust/src/libproc_macro)
[00:51:20]    Compiling syntax_ext v0.0.0 (file:///Users/travis/build/rust-lang/rust/src/libsyntax_ext)

No output has been received in the last 30m0s, this potentially indicates a stalled build or something wrong with the build itself.
Check the details on how to adjust your build configuration on: https://docs.travis-ci.com/user/common-build-problems/#Build-times-out-because-no-output-was-received

The build has been terminated

First appeared with high frequency since 2018 Jan 18th.

Historical record:

Time	PR	Log	Last compiled package
2018-01-16T14:34:10Z	#47035 (comment)	check 64 + check 32	stage0: syntax_ext
2018-01-18T08:46:24Z	#47528 (comment)	check 32	stage0: rustc_errors
2018-01-18T09:54:11Z	#47431 (comment)	check 64 + check 32	stage0: syntax_ext
2018-01-18T11:10:10Z	#47528 (comment)	check 64	stage0: rustc_typeck

[kennytm]

Maybe also relevant:

• Rollup of 12 pull requests #47350 (comment)

  Building stage1 compiler artifacts (x86_64-apple-darwin -> x86_64-apple-darwin)
  [00:45:49]    Compiling libc v0.2.35
  [00:45:49]    Compiling rustc-serialize v0.3.24
  [00:45:50]    Compiling lazy_static v0.2.11
  ...
  [00:51:06]    Compiling rustc_const_math v0.0.0 (file:///Users/travis/build/rust-lang/rust/src/librustc_const_math)
  [00:51:06]    Compiling proc_macro v0.0.0 (file:///Users/travis/build/rust-lang/rust/src/libproc_macro)
  [00:51:20]    Compiling syntax_ext v0.0.0 (file:///Users/travis/build/rust-lang/rust/src/libsyntax_ext)
  
  No output has been received in the last 30m0s, this potentially indicates a stalled build or something wrong with the build itself.
  Check the details on how to adjust your build configuration on: https://docs.travis-ci.com/user/common-build-problems/#Build-times-out-because-no-output-was-received
  
  The build has been terminated
  

• [beta] Automaticaly calculate beta prerelease numbers #47396 (comment)

  ...
  [01:38:07] test [run-pass] run-pass/zero-size-type-destructors.rs ... �[32mok�(B�[m
  [01:38:07] test [run-pass] run-pass/zero-sized-binary-heap-push.rs ... �[32mok�(B�[m
  [01:38:08] test [run-pass] run-pass/zero-sized-btreemap-insert.rs ... �[32mok�(B�[m
  [01:42:02] test [run-pass] run-pass/zero-sized-linkedlist-push.rs has been running for over 60 seconds
  [01:42:02] test [run-pass] run-pass/zero-sized-tuple-struct.rs has been running for over 60 seconds
  
  No output has been received in the last 30m0s, this potentially indicates a stalled build or something wrong with the build itself.
  Check the details on how to adjust your build configuration on: https://docs.travis-ci.com/user/common-build-problems/#Build-times-out-because-no-output-was-received
  
  The build has been terminated
  

[kennytm]

Travis status page now shows "Partially Degraded Service" for Mac Builds but no official incident update yet.

[alexcrichton]

Looks like we have an official incident now. The first linked log comes from the 16th, but Travis often takes multiple days to diagnose an incident sometimes.

[alexcrichton]

I believe this was since resolved, so closing.