race condition in Eventually

[amir-arad]

I've used a tightly timed 'Eventually' in my test:
assert.Eventually(t, func() bool { ... }, time.Millisecond*100, time.Millisecond)
ran it with -race -count=1000 and i got:

==================
WARNING: DATA RACE
Write at 0x00c0000ba5b0 by goroutine 34:
  runtime.closechan()
      /.../go/go1.12.9/src/runtime/chan.go:334 +0x0
  github.com/stretchr/testify/assert.Eventually()
      /.../go/go1.12.9/pkg/mod/github.com/stretchr/[email protected]/assert/assertions.go:1490 +0x29e
  github.com/stretchr/testify/require.Eventually()
      /.../go/go1.12.9/pkg/mod/github.com/stretchr/[email protected]/require/require.go:278 +0xaf
  command-line-arguments_test.TestPeriodicalTriggerStopWorksWhenContextIsCancelled.func1()
    ...

Previous read at 0x00c0000ba5b0 by goroutine 62:
  runtime.chansend()
      /.../go/go1.12.9/src/runtime/chan.go:142 +0x0
  github.com/stretchr/testify/assert.Eventually.func1()
      /.../go/go1.12.9/pkg/mod/github.com/stretchr/[email protected]/assert/assertions.go:1494 +0x54

[perhallgren]

Same here! Not able to reproduce reliably. go version go1.13 darwin/amd64, using github.com/stretchr/testify v1.4.0.

==================
WARNING: DATA RACE
Read at 0x00c000468010 by goroutine 17:
  runtime.chansend()
      /usr/local/opt/go/libexec/src/runtime/chan.go:142 +0x0
  github.com/stretchr/testify/assert.Eventually.func1()

Previous write at 0x00c000468010 by goroutine 91:
  runtime.closechan()
      /usr/local/opt/go/libexec/src/runtime/chan.go:334 +0x0
  github.com/stretchr/testify/assert.Eventually()

Looks like this is the issue.