[Patch] lit.cfg: better check for MSYS

[Hans Wennborg]

On Mon, Jul 29, 2013 at 3:28 PM, Reid Kleckner <rnk at google.com> wrote:
> bash -help is pretty fast to start, but it also seems pretty heavyweight for
> lit.cfg.  It's probably better to check not execute_external like this:
>
> $ git diff test/lit.cfg
> diff --git a/test/lit.cfg b/test/lit.cfg
> index a5bb350..f2f16fb 100644
> --- a/test/lit.cfg
> +++ b/test/lit.cfg
> @@ -245,7 +245,7 @@ if execute_external:
>      config.available_features.add('shell')
>
>  # Exclude MSYS due to transforming '/' to 'X:/mingwroot/'.
> -if not platform.system() in ['Windows'] or lit.getBashPath() == '':
> +if not platform.system() in ['Windows'] or not execute_external:
>      config.available_features.add('shell-preserves-root')

That sounds good to me. Takumi, what do you think about this change? I
see we do (almost) the same check earlier in the file, in
getClangBuiltinIncludeDir().

 - Hans

> On Mon, Jul 29, 2013 at 1:57 PM, Hans Wennborg <hans at chromium.org> wrote:
>>
>> On Mon, Jul 29, 2013 at 11:44 AM, Reid Kleckner <rnk at google.com> wrote:
>> > On Mon, Jul 29, 2013 at 11:33 AM, Hans Wennborg <hans at chromium.org>
>> > wrote:
>> >>
>> >> On Mon, Jul 29, 2013 at 11:01 AM, NAKAMURA Takumi
>> >> <geek4civic at gmail.com>
>> >> wrote:
>> >> > I suppose that system's python should be /usr/bin/python in Cygwin's
>> >> > world.
>> >> > I didn't know Python/win32 could run Lit for cygwin tests.
>> >> >
>> >> > What is a motivation for you to take *external* python on cygwin?
>> >>
>> >> I build Clang outside Cygwin, in cmd.exe, because I want to build in a
>> >> "pure win32" environment. But I fail at running the tests in cmd.exe,
>> >> so I use Cygwin to run the tests.
>> >>
>> >> If I try to use Cygwin's /usr/bin/python to run the tests, it fails
>> >> because of some Windows path. Probably because I didn't build in
>> >> Cygwin.
>> >>
>> >> I guess my configuration is confusing to lit.cfg, because I have
>> >> platform.system() = "Windows" and lit.getBashPath() =
>> >> "C:\src\cygwin\bin\bash.EXE". But it's still not MSYS :)
>> >
>> >
>> > This configuration is pretty handy because it's way faster to spawn
>> > processes from native win32 python than from cygwin bash or cygwin
>> > python.
>> >
>> > I think the odd duck that we should be checking for here is MSys, so
>> > using
>> > the MSYSTEM env var sounds good to me.
>>
>> I got paranoid and started worrying about the possibility of MSYS bash
>> ending up on the path, even if the test suite is started outside an
>> MSYS shell. In that case, looking for $MSYSTEM wouldn't work.
>>
>> Maybe we should just ask the bash binary which version it has? I'm
>> attaching a patch that does that, please take a look.
>>
>> I realize this isn't super important, as the tests are still being run
>> by the cygwin buildbots, but it would be nice if this configuration
>> were supported too.
>>
>> Thanks,
>> Hans
>
>