Re: [PATCH v7 5/8] Acceptance tests: keep a stable reference to the QEMU build dir

[Cleber Rosa]

On Thu, Nov 07, 2019 at 05:22:24PM -0200, Wainer dos Santos Moschetta wrote:
> 
> On 11/4/19 1:13 PM, Cleber Rosa wrote:
> > This is related to the the differences in in-tree and out-of-tree
> > builds in QEMU.  For simplification, <BLD> means my build directory.
> > 
> > Currently, by running a `make check-acceptance` one gets (in
> > tests/acceptance/avocado_qemu/__init__.py):
> > 
> >     SRC_ROOT_DIR: <BLD>/tests/acceptance/avocado_qemu/../../..
> > 
> > This in itself is problematic, because after the parent directories
> > are applied, one may be left not with a pointer to the build directory
> > as intended, but with the location of the source tree (assuming they
> > differ). Built binaries, such as qemu-img, are of course not there and
> > can't be found.
> > 
> > Given that a Python '__file__' will contain the absolute path to the
> > file backing the module, say:
> > 
> >     __file__: <BLD>/tests/acceptance/avocado_qemu/__init__.py
> > 
> >                    |  4  |     3    |      2     |     1     |
> > 
> > A solution is to not "evaluate" the third parent dir (marked as 4
> > here) because that ends up following the "tests" directory symlink to
> > the source tree.  In fact, there's no need to keep or evaluate any of
> > the parent directories, we can just drop the rightmost 4 components,
> > and we'll keep a stable reference to the build directory (with no
> > symlink being followed).  This works for either a dedicated build
> > directory or also a combined source and build tree.
> > 
> > Signed-off-by: Cleber Rosa <address@hidden>
> > ---
> >   tests/acceptance/avocado_qemu/__init__.py | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/tests/acceptance/avocado_qemu/__init__.py 
> > b/tests/acceptance/avocado_qemu/__init__.py
> > index 6618ea67c1..17ce583c87 100644
> > --- a/tests/acceptance/avocado_qemu/__init__.py
> > +++ b/tests/acceptance/avocado_qemu/__init__.py
> > @@ -16,7 +16,7 @@ import tempfile
> >   import avocado
> > -SRC_ROOT_DIR = os.path.join(os.path.dirname(__file__), '..', '..', '..')
> > +SRC_ROOT_DIR = 
> > os.path.dirname(os.path.dirname(os.path.dirname(os.path.dirname(__file__))))
> 
> In this case, wouldn't make sense to rename the constant from SRC_ROOT_DIR
> to BUILD_ROOT_DIR?
>

True.  I remember thinking about doing that as a separate change and
ended up forgetting.  Maybe it's better to just do it here.

> This patch looks good to me besides that.
> 
> - Wainer
>

Thanks!
- Cleber.