Thanks!
Had missed the spawning of a new process part.
From: Ben Gamari
Sent: Saturday, October 15, 2016 00:12
To: lonetiger@gmail.com; ghc-devs@haskell.org
Subject: Re: Testsuite threadsafety
lonetiger@gmail.com writes:
> Hi *,
>
> I’m trying to understand a few pieces of code in the testsuite,
>
> As it so happens quite a few tests randomly fail on newer msys2 and python installs:
>
> r:/temp/ghctest-0u4c8o/test spaces/./th/T12407.run T12407 [ext-interp] ([Error 183] Cannot create a file when that file already exists: 'r:/temp/ghctest-0u4c8o/test spaces/./th/T12407.run')
> r:/temp/ghctest-0u4c8o/test spaces/./th/T11463.run T11463 [ext-interp] ([Error 183] Cannot create a file when that file already exists: 'r:/temp/ghctest-0u4c8o/test spaces/./th/T11463.run')
> r:/temp/ghctest-0u4c8o/test spaces/./th/T12478_4.run T12478_4 [ext-interp] ([Error 183] Cannot create a file when that file already exists: 'r:/temp/ghctest-0u4c8o/test spaces/./th/T12478_4.run')
> r:/temp/ghctest-0u4c8o/test spaces/./th/T12478_3.run T12478_3 [ext-interp] ([Error 183] Cannot create a file when that file already exists: 'r:/temp/ghctest-0u4c8o/test spaces/./th/T12478_3.run')
>
> (I say random, but the set of tests seem to be the same ones, just within that group a few randomly pass every so often. It’s mostly TH tests.)
>
> Anyone have any ideas? I’m not very familiar with the internals of the testsuite.
>
> Secondly, I’ve noticed all paths in the testsuite are relative paths. And this hand me wondering, relative to what.
>
> I see that in do_test we actually change directories
>
> 837 if opts.pre_cmd:
> 838 exit_code = runCmd('cd "{0}" && {1}'.format(opts.testdir, opts.pre_cmd))
>
If I understand this correctly, this is merely spawning off a child
shell process which then moves its own cwd to opts.testdir. This should
not affect the cwd of the testsuite driver, which means that it should
be perfectly safe.
Cheers,
- Ben