Race detected when send command to the running proxy

[euiko]

To reproduce this just call the proxy run, and perform RawCommands and test it with -race option, it should give detected race conditions in many cases.
Or just build the provided example with -race option.

Look like there is a race condition on reading std out/err while waiting spawned program to be exited through calls cmd.Wait() such as mentioned in issue golang/go#19685
Consider fix like mentioned in the comments golang/go#19685 (comment)
But the observed behavior look like doesn't directly impact the functionality of the library and still need to be checked more in depth

[galihrivanto]

while I will try to add unit test for racescenario, can you test whether latest release have similar issue v0.1.1?
https://github.com/galihrivanto/go-inkscape/releases/tag/v0.1.1

[euiko]

the issue is also reproduced on v0.1.1 tag
here is the git log that I've checked out :

commit c34a6a45609ed40f2e5be9b16de462d3287d3c1c (HEAD, tag: v0.1.1, origin/master, origin/HEAD, master)
Author: galih rivanto <[email protected]>
Date:   Fri Feb 5 16:04:21 2021 +0700

    fix race during proxy running

the issue still existed as with below race information :

> ./svg2pdf -input test.svg -output out.pdf
==================
WARNING: DATA RACE
Write at 0x00c000300000 by goroutine 10:
  internal/race.WriteRange()
      /usr/lib/go/src/internal/race/race.go:49 +0x9a
  syscall.Read()
      /usr/lib/go/src/syscall/syscall_unix.go:190 +0x7e
  internal/poll.(*FD).Read.func1()
      /usr/lib/go/src/internal/poll/fd_unix.go:155 +0xa4
  internal/poll.ignoringEINTR()
      /usr/lib/go/src/internal/poll/fd_unix.go:567 +0x38
  internal/poll.(*FD).Read()
      /usr/lib/go/src/internal/poll/fd_unix.go:155 +0x1cd
  os.(*File).read()
      /usr/lib/go/src/os/file_posix.go:31 +0xb1
  os.(*File).Read()
      /usr/lib/go/src/os/file.go:116 +0x6b
  io.copyBuffer()
      /usr/lib/go/src/io/io.go:409 +0x14b
  io.Copy()
      /usr/lib/go/src/io/io.go:368 +0x7a
  os/exec.(*Cmd).writerDescriptor.func1()
      /usr/lib/go/src/os/exec/exec.go:311 +0x4a
  os/exec.(*Cmd).Start.func1()
      /usr/lib/go/src/os/exec/exec.go:441 +0x38

Previous read at 0x00c000300000 by main goroutine:
  bytes.Index()
      /usr/lib/go/src/bytes/bytes.go:1116 +0x18d
  bytes.Contains()
      /usr/lib/go/src/bytes/bytes.go:76 +0x469
  github.com/galihrivanto/go-inkscape.(*Proxy).sendCommand()
      /home/euiko/Sources/galihrivanto/go-inkscape/proxy.go:213 +0x3f0
  github.com/galihrivanto/go-inkscape.(*Proxy).RawCommands()
      /home/euiko/Sources/galihrivanto/go-inkscape/proxy.go:233 +0x1de
  github.com/galihrivanto/go-inkscape.(*Proxy).Svg2Pdf()
      /home/euiko/Sources/galihrivanto/go-inkscape/proxy.go:238 +0x199
  main.main()
      /home/euiko/Sources/galihrivanto/go-inkscape/cmd/svg2pdf/main.go:38 +0x36f

Goroutine 10 (running) created at:
  os/exec.(*Cmd).Start()
      /usr/lib/go/src/os/exec/exec.go:440 +0xaaa
  github.com/galihrivanto/go-inkscape.(*Proxy).runBackground()
      /home/euiko/Sources/galihrivanto/go-inkscape/proxy.go:104 +0x404
  github.com/galihrivanto/go-inkscape.(*Proxy).Run.func1.1()
      /home/euiko/Sources/galihrivanto/go-inkscape/proxy.go:128 +0x86
  github.com/galihrivanto/runner.doOperation()
      /home/euiko/Sources/go/pkg/mod/github.com/galihrivanto/[email protected]/runner.go:98 +0x89
  github.com/galihrivanto/runner.RunWithRetry.func1()
      /home/euiko/Sources/go/pkg/mod/github.com/galihrivanto/[email protected]/runner.go:111 +0x9a
==================
==================
WARNING: DATA RACE
Write at 0x00c000300001 by goroutine 10:
  internal/race.WriteRange()
      /usr/lib/go/src/internal/race/race.go:49 +0x9a
  syscall.Read()
      /usr/lib/go/src/syscall/syscall_unix.go:190 +0x7e
  internal/poll.(*FD).Read.func1()
      /usr/lib/go/src/internal/poll/fd_unix.go:155 +0xa4
  internal/poll.ignoringEINTR()
      /usr/lib/go/src/internal/poll/fd_unix.go:567 +0x38
  internal/poll.(*FD).Read()
      /usr/lib/go/src/internal/poll/fd_unix.go:155 +0x1cd
  os.(*File).read()
      /usr/lib/go/src/os/file_posix.go:31 +0xb1
  os.(*File).Read()
      /usr/lib/go/src/os/file.go:116 +0x6b
  io.copyBuffer()
      /usr/lib/go/src/io/io.go:409 +0x14b
  io.Copy()
      /usr/lib/go/src/io/io.go:368 +0x7a
  os/exec.(*Cmd).writerDescriptor.func1()
      /usr/lib/go/src/os/exec/exec.go:311 +0x4a
  os/exec.(*Cmd).Start.func1()
      /usr/lib/go/src/os/exec/exec.go:441 +0x38

Previous read at 0x00c000300001 by main goroutine:
  bytes.Index()
      /usr/lib/go/src/bytes/bytes.go:1125 +0x1e6
  bytes.Contains()
      /usr/lib/go/src/bytes/bytes.go:76 +0x469
  github.com/galihrivanto/go-inkscape.(*Proxy).sendCommand()
      /home/euiko/Sources/galihrivanto/go-inkscape/proxy.go:213 +0x3f0
  github.com/galihrivanto/go-inkscape.(*Proxy).RawCommands()
      /home/euiko/Sources/galihrivanto/go-inkscape/proxy.go:233 +0x1de
  github.com/galihrivanto/go-inkscape.(*Proxy).Svg2Pdf()
      /home/euiko/Sources/galihrivanto/go-inkscape/proxy.go:238 +0x199
  main.main()
      /home/euiko/Sources/galihrivanto/go-inkscape/cmd/svg2pdf/main.go:38 +0x36f

Goroutine 10 (running) created at:
  os/exec.(*Cmd).Start()
      /usr/lib/go/src/os/exec/exec.go:440 +0xaaa
  github.com/galihrivanto/go-inkscape.(*Proxy).runBackground()
      /home/euiko/Sources/galihrivanto/go-inkscape/proxy.go:104 +0x404
  github.com/galihrivanto/go-inkscape.(*Proxy).Run.func1.1()
      /home/euiko/Sources/galihrivanto/go-inkscape/proxy.go:128 +0x86
  github.com/galihrivanto/runner.doOperation()
      /home/euiko/Sources/go/pkg/mod/github.com/galihrivanto/[email protected]/runner.go:98 +0x89
  github.com/galihrivanto/runner.RunWithRetry.func1()
      /home/euiko/Sources/go/pkg/mod/github.com/galihrivanto/[email protected]/runner.go:111 +0x9a
==================
done!!
Found 2 data race(s)
[1]    84900 exit 66    ./svg2pdf -input test.svg -output out.pdf

[euiko]

Please review the PR #2

[galihrivanto]

should be closed by #2