Re: [Qemu-block] [PATCH] tests: Fix Python 3 detection on older GNU make versions

[Markus Armbruster]

Eduardo Habkost <address@hidden> writes:

> The $(SHELLSTATUS) variable requires GNU make >= 4.2, but Travis
> seems to provide an older version.  Change the existing rules to
> use command output instead of exit code, to make it compatible
> with older GNU make versions.
>
> Signed-off-by: Eduardo Habkost <address@hidden>
> ---
> I think that's the cause of the Travis failures.  I have
> submitted a test job right now, at:
>   https://travis-ci.org/ehabkost/qemu-hacks/jobs/451387962
> Let's see if it fixes the issue.
> ---
>  tests/Makefile.include | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/tests/Makefile.include b/tests/Makefile.include
> index d2e577eabb..074eece558 100644
> --- a/tests/Makefile.include
> +++ b/tests/Makefile.include
> @@ -913,8 +913,8 @@ TESTS_RESULTS_DIR=$(BUILD_DIR)/tests/results
>  # information please refer to "avocado --help".
>  AVOCADO_SHOW=none
>  
> -$(shell $(PYTHON) -c 'import sys; assert sys.version_info >= (3,0)' 
> >/dev/null 2>&1)
> -ifeq ($(.SHELLSTATUS),0)
> +PYTHON3 = $(shell $(PYTHON) -c 'import sys; print(1 if sys.version_info >= 
> (3, 0) else 0)')
> +ifeq ($(PYTHON3), 1)
>  $(TESTS_VENV_DIR): $(TESTS_VENV_REQ)
>       $(call quiet-command, \
>              $(PYTHON) -m venv --system-site-packages $@, \

PEP 394 recommends software distributions install Python 3 into the
default path as python3, and users use that instead of python, except
for programs that are source compatible with both 2 and 3.  So, is
finding out whether python is a Python 3 really appropriate?  Why can't
we just use python3 and be done with it?

If we can't: isn't this a configure problem?