cmd/compile: fatal error on Mac when caller changes stdout buffering

[kevinburke]

Please answer these questions before submitting your issue. Thanks!

What did you do?

1. Install coreutils package on Mac: brew install coreutils

2. Attempt to run a Go program with line buffering output:

gstdbuf --output=L go test ./...

What did you expect to see?

I expected the tests to run.

What did you see instead?

$ gstdbuf --output=0 go test ./...
go tool compile: exit status 2
fatal error: runtime: bsdthread_register error (unset DYLD_INSERT_LIBRARIES)

runtime stack:
runtime.throw(0x183236f, 0x3f)
	/Users/kevin/go/src/runtime/panic.go:589 +0x72 fp=0x7ffeefbff298 sp=0x7ffeefbff268 pc=0x102a272
runtime.goenvs()
	/Users/kevin/go/src/runtime/os_darwin.go:127 +0x9c fp=0x7ffeefbff2c8 sp=0x7ffeefbff298 pc=0x10280bc
runtime.schedinit()
	/Users/kevin/go/src/runtime/proc.go:505 +0xd3 fp=0x7ffeefbff330 sp=0x7ffeefbff2c8 pc=0x102cbc3
runtime.rt0_go(0x7ffeefbff360, 0x2, 0x7ffeefbff360, 0x0, 0x2, 0x7ffeefbff5f8, 0x7ffeefbff626, 0x0, 0x7ffeefbff62e, 0x7ffeefbff684, ...)
	/Users/kevin/go/src/runtime/asm_amd64.s:223 +0x187 fp=0x7ffeefbff338 sp=0x7ffeefbff330 pc=0x1053887
go tool compile: exit status 2
fatal error: runtime: bsdthread_register error (unset DYLD_INSERT_LIBRARIES)

runtime stack:
runtime.throw(0x183236f, 0x3f)
	/Users/kevin/go/src/runtime/panic.go:589 +0x72 fp=0x7ffeefbff298 sp=0x7ffeefbff268 pc=0x102a272
runtime.goenvs()
	/Users/kevin/go/src/runtime/os_darwin.go:127 +0x9c fp=0x7ffeefbff2c8 sp=0x7ffeefbff298 pc=0x10280bc
runtime.schedinit()
	/Users/kevin/go/src/runtime/proc.go:505 +0xd3 fp=0x7ffeefbff330 sp=0x7ffeefbff2c8 pc=0x102cbc3
runtime.rt0_go(0x7ffeefbff360, 0x2, 0x7ffeefbff360, 0x0, 0x2, 0x7ffeefbff5f8, 0x7ffeefbff626, 0x0, 0x7ffeefbff62e, 0x7ffeefbff684, ...)
	/Users/kevin/go/src/runtime/asm_amd64.s:223 +0x187 fp=0x7ffeefbff338 sp=0x7ffeefbff330 pc=0x1053887

Does this issue reproduce with the latest release (go1.10.1)?

Yes

System details

go version devel +adb52cff58 Fri Apr 27 20:57:51 2018 +0000 darwin/amd64
GOARCH="amd64"
GOBIN=""
GOCACHE="/Users/kevin/Library/Caches/go-build"
GOEXE=""
GOHOSTARCH="amd64"
GOHOSTOS="darwin"
GOOS="darwin"
GOPATH="/Users/kevin"
GORACE=""
GOROOT="/Users/kevin/go"
GOTMPDIR=""
GOTOOLDIR="/Users/kevin/go/pkg/tool/darwin_amd64"
GCCGO="gccgo"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -fmessage-length=0 -fdebug-prefix-map=/var/folders/sf/fsn3_vgd0n98r0jb86bgp83r0000gn/T/go-build352001371=/tmp/go-build -gno-record-gcc-switches -fno-common"
GOROOT/bin/go version: go version devel +adb52cff58 Fri Apr 27 20:57:51 2018 +0000 darwin/amd64
GOROOT/bin/go tool compile -V: compile version devel +adb52cff58 Fri Apr 27 20:57:51 2018 +0000
uname -v: Darwin Kernel Version 17.5.0: Mon Mar  5 22:24:32 PST 2018; root:xnu-4570.51.1~1/RELEASE_X86_64
ProductName:	Mac OS X
ProductVersion:	10.13.4
BuildVersion:	17E199
lldb --version: lldb-900.0.57
  Swift-4.0

[kevinburke]

To be clear line buffering doesn't matter / isn't important for this particular program. It was just the first thing I thought of when I wanted to test out stdbuf/gstdbuf, and it turns out it panics and I figured at the very least we could prevent a panic there or present a better error message.

If the answer is "don't run your program after messing with the line buffer" that's fine too.

[randall77]

This may be fixed as part of #17490. If you have a chance, try to rebuild the Go distribution using the pending CL on that issue and report back whether it fixes this issue.

[kevinburke]

I rebuilt with the pending CL. The first time I ran gstdbuf --output=0 go test ./... I got go tool: no such tool "vet". I then ran the same prefix with go install ./... and go test ./... and the second time I ran the tests, they passed with no problems.

[ianlancetaylor]

@kevinburke Is there anything else to do here?

[kevinburke]

I don't think so...