Re: [PATCH] Update git-p4 to be compatible with git-lfs 1.2

From: SZEDER Gábor <szeder@ira.uka.de>
Date: Apr 25, 2016, 23:10 UTC
Message-ID: <20160426011056.Horde.yl47nWMpVGsuGDgrKiKb_nR@webmail.informatik.kit.edu>
In-Reply-To: <xmqq8u01mwji.fsf@gitster.mtv.corp.google.com>

Quoting Junio C Hamano <gitster@pobox.com>:

Show 24 quoted lines

> SZEDER Gábor <szeder@ira.uka.de> writes:
>
>> You can have a look at these patches at
>>
>>   https://github.com/szeder/git completion-test-multiple-bash-versions
>>
>> and perhaps you could even adapt it to LFS and/or p4 somehow.
>>
>>> Plus if we want to be consistent we would
>>> need to do the same for LFS 1.0, 1.2, and for pretty much every other
>>> dependency...
>>
>> I'm not sure we should be consistent in this case, at least not solely
>> for consistency's sake and not in git.git. Taking what I did for Bash
>> and doing it for different versions of LFS, p4, etc. could perhaps
>> keep the runtime under control, but t/Makefile would surely get out
>> of control rather quickly.  Putting these into a travis-ci matrix is
>> so much simpler, but the runtime makes it infeasible, of course.
>
> I took a brief look of your branch, and I like its approach.  If I
> understood your approach correctly, you:
>
>  * Group selected tests in t/ as "these are bash related tests I
>    care about" in t/Makefile;

Yes.

>  * Add Travis test target to build Git with specific versions of
>    bash, and run the above target instead of the full test to
>    exercise the version of bash you are testing.

Not quite.

   * Add t/Makefile targets to run a Bash-related test script with a
     specific Bash version, one target for each script-version pair,
     and a target to run all Bash-related tests with all listed
     Bash-versions.

   * Extend the travis-ci config so that, after building Git as usual
     and running the full test suite as usual, it additionaly runs all
     Bash-related tests will all listed Bash versions on Linux builds.

> And I agree that the same can be done for LFS versions and P4
> versions.  Only a handful tests in t/ are about these niches.

Luckily for me, running a test script with a specific Bash version is as trivial as '/path/to/bash-vX.Y t9902-completion.sh'. No modifications to the test scripts or to lib-bash.sh were necessary.

OTOH, Git LFS and p4 tests, AFAICS, rely on git-lfs and p4 binaries being available in $PATH, and the p4 tests need two binaries. So there is more work that has to be done, as we would need a way to override those binaries found in $PATH, either through an environment variable or a command line option. Bonus points for a solution that would work equally well with LFS, p4 and Bash: then perhaps we could have a single unified block of Makefile metaprogramming, which could generate all those test targets from a list of dependency-specific tests and a list of paths to different versions of that dependency. Then it might even be suitable for inclusion in git.git.

>> I think the best we can do is to keep this out of git.git and let
>> (hope?) developers interested in a particular subsystem do this
>> "multiple version compatibility" tests as they see fit.