Re: [Qemu-devel] [PATCH] iotests: Use configured python

[Fam Zheng <famz@redhat.com>]

On Thu, 05/15 01:41, Max Reitz wrote:
> On 14.05.2014 14:33, Markus Armbruster wrote:
> >Max Reitz <mreitz@redhat.com> writes:
> >
> >>Currently, QEMU's iotests rely on /usr/bin/env to start the correct
> >>Python (that is, at least Python 2.4, but not 3). On systems where
> >>Python 3 is the default, the user has no clean way of making the iotests
> >>use the correct binary.
> >>
> >>This commit makes the iotests use the Python selected by configure.
> >>
> >>Signed-off-by: Max Reitz <mreitz@redhat.com>
> >I'm afraid this broke qemu-iotests in a separate build tree:
> >
> >     ./check: line 38: ./common.env: No such file or directory
> 
> As I already replied to Peter, I see two (or maybe three) ways to fix this:
> 
> The first is, we use the correct path to common.env. This would however
> result in modification of the source tree although this is probably not what
> the user intends with an out-of-tree build. On the other hand, this would
> just work.
> 
> The second is, we do not create common.env for out-of-tree builds and add a
> default common.env to the repository ("PYTHON = python" should probably
> suffice). This would not introduce any regressions, however, the iotests
> would remain problematic on systems with Python 3 being the default when
> using out-of-tree builds. As I guess that out-of-tree builds are actually
> recommended, this would mean that the better solution might be to revert my
> patch and instead change every "python" occurrence in the iotests' Shebangs
> to "python2", as kind of a third way to go. However, for this I'm not sure
> whether all systems which are supposed to be supported by qemu actually have
> a "python2" executable/symlink. I guess so, but then again...
> 
> So, either we fix it but try to write to the source tree without the user
> intending to modify it; or we fix it for in-tree builds only; or we drop the
> magic and just use "python2" in the iotests' Shebangs.

Why can't we just tell ./check the path to common.env with an env var, like how
we tell ./check the path to qemu-img with QEMU_IMG_PROG?

Fam