os: Test*EOF flaky

[bcmills]

darwin-amd64-10_14 (https://build.golang.org/log/e527731127351d19a8868d360bd6b534590f69f0):

--- FAIL: TestFifoEOF (60.05s)
    fifo_test.go:100: line 0
    fifo_test.go:100: line 1
    fifo_test.go:100: line 2
    fifo_test.go:108: timed out waiting for read
    fifo_test.go:86: error closing reader: close /var/folders/9w/4l2_g3kx01x199n37fbmv3s80000gn/T/workdir-host-darwin-10_14/tmp/TestFifoEOF585114092/fifo: file already closed
FAIL
FAIL	os	60.911s

May relate to #25877 (CC @ianlancetaylor).

[bcmills]

A very similar failure in TestPipeEOF on aix-ppc64 (https://build.golang.org/log/836b814bee1107744a77bf2767d3f240586f6028):

--- FAIL: TestPipeEOF (1.01s)
    pipe_test.go:378: line 0
    pipe_test.go:378: line 1
    pipe_test.go:386: timed out waiting for read
    pipe_test.go:378: line 2
    pipe_test.go:375: read |0: file already closed
    pipe_test.go:364: error closing reader: close |0: file already closed
FAIL
FAIL	os	1.941s

[mknyszek]

Seen on trybots (windows-386-2008), and I'm 99% it's not related to those changes: https://storage.googleapis.com/go-build-log/5064a99f/windows-386-2008_ac9f4654.log

--- FAIL: TestPipeEOF (1.00s)
    pipe_test.go:378: line 0
    pipe_test.go:378: line 1
    pipe_test.go:378: line 2
    pipe_test.go:386: timed out waiting for read
    pipe_test.go:375: read |0: file already closed
    pipe_test.go:364: error closing reader: close |0: file already closed
FAIL
FAIL	os	3.570s

[ianlancetaylor]

So far, the TestFifoEOF error is happening only on Darwin. The TestPipeEOF error has not yet been seen on Darwin. Though I agree they look quite similar.

2019-10-30T21:43:57-6becb03/darwin-arm-mg912baios
2019-10-31T09:49:57-1085560/darwin-amd64-10_14
2019-10-31T09:49:57-1085560/darwin-arm64-corellium
2019-10-31T17:21:56-48c0cef/darwin-386-10_14

[mknyszek]

@ianlancetaylor I saw a TestFifoEOF error on a linux/amd64 trybot just now: https://storage.googleapis.com/go-build-log/22734f54/linux-amd64_a7c99ff2.log

--- FAIL: TestFifoEOF (1.01s)
    fifo_test.go:108: timed out waiting for read
    fifo_test.go:100: line 0
    fifo_test.go:97: read /workdir/tmp/TestFifoEOF684921827/fifo: file already closed
    fifo_test.go:86: error closing reader: close /workdir/tmp/TestFifoEOF684921827/fifo: file already closed
    fifo_test.go:66: error writing to fifo: write /workdir/tmp/TestFifoEOF684921827/fifo: broken pipe
FAIL
FAIL	os	1.601s

[ianlancetaylor]

Thanks. I haven't had any luck reproducing this.

[ianlancetaylor]

There is certainly a chance that this will be fixed by https://golang.org/cl/204800, but it's hard to know for sure.

[FiloSottile]

https://storage.googleapis.com/go-build-log/52250b89/windows-386-2008_e048933d.log

--- FAIL: TestPipeEOF (1.00s)
    pipe_test.go:378: line 0
    pipe_test.go:378: line 1
    pipe_test.go:378: line 2
    pipe_test.go:386: timed out waiting for read
    pipe_test.go:364: error closing reader: close |0: file already closed

From the https://golang.org/cl/204377 TryBot.

[ianlancetaylor]

CL 204800 is still awaiting review.

[ianlancetaylor]

This hasn't happened since https://golang.org/cl/204800 was committed. It is almost certainly fixed.