Pallinder/go-randomdata

privateRand is not safe for concurrent use

andy opened this issue · 3 comments

andy commented

It should be either wrapped in a lock or global rand package object must be used. Quoting rand#NewSource documentation: https://golang.org/pkg/math/rand/#NewSource

NewSource returns a new pseudo-random Source seeded with the given value. Unlike the default Source used by top-level functions, this source is not safe for concurrent use by multiple goroutines.
andy commented

Here is a sample of what go builtin race detector reports:

Read at 0x00c0001c2000 by goroutine 251:
  math/rand.(*rngSource).Int63()
      /usr/local/Cellar/go/1.12/libexec/src/math/rand/rng.go:239 +0x3f
  math/rand.(*Rand).Int31n()
      /usr/local/Cellar/go/1.12/libexec/src/math/rand/rand.go:85 +0x84
  math/rand.(*Rand).Intn()
      /usr/local/Cellar/go/1.12/libexec/src/math/rand/rand.go:172 +0x52
  .../vendor/github.com/Pallinder/go-randomdata.FirstName()
      .../vendor/github.com/Pallinder/go-randomdata/random_data.go:88 +0x19e
  .../vendor/github.com/Pallinder/go-randomdata.FirstName()
      .../vendor/github.com/Pallinder/go-randomdata/random_data.go:119 +0x13f

Previous write at 0x00c0001c2000 by goroutine 250:
  math/rand.(*rngSource).Int63()
      /usr/local/Cellar/go/1.12/libexec/src/math/rand/rng.go:239 +0x55
  math/rand.(*Rand).Int31n()
      /usr/local/Cellar/go/1.12/libexec/src/math/rand/rand.go:85 +0x84
  math/rand.(*Rand).Intn()
      /usr/local/Cellar/go/1.12/libexec/src/math/rand/rand.go:172 +0x52
  .../vendor/github.com/Pallinder/go-randomdata.FirstName()
      .../vendor/github.com/Pallinder/go-randomdata/random_data.go:88 +0x19e
  .../vendor/github.com/Pallinder/go-randomdata.FirstName()
      .../vendor/github.com/Pallinder/go-randomdata/random_data.go:119 +0x13f
Pallinder commented

Thanks for this, would love a PR if you have one so we can get this fixed in a release.

Pallinder commented

Released in v1.2.0

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