Re: [PATCH] progress.c tests: fix breakage with COLUMNS != 80

[Philip Oakley <philipoakley@iee.email>]

On 24/06/2021 00:48, Jeff King wrote:
> On Mon, Jun 21, 2021 at 09:01:23AM +0200, Ævar Arnfjörð Bjarmason wrote:
>
>> The tests added in 2bb74b53a49 (Test the progress display, 2019-09-16)
>> broke under anything except COLUMNS=80, i.e. when running them under
>> the "-v" mode under a differently sized terminal.
>>
>> Let's set the expected number of COLUMNS at the start of the test to
>> fix that bug. It's handy not do do this in test-progress.c itself, in
>> case we'd like to test for a different number of COLUMNS, either
>> manually or in a future test.
> Hmm. So I can easily reproduce the problem here, and your patch fixes
> it. But my first thought was: shouldn't test-lib.sh be handling this to
> give all of the scripts a uniform environment?
>
> And indeed, we _do_ unset COLUMNS there. So I think the problem isn't
> a bad setting of $COLUMNS, but rather that in "-v" mode, the
> sub-command's stderr is hooked to our tty, and term_columns() is smart
> enough to use TIOCGWINSZ to get the value (at least on some platforms).
>
> Setting $COLUMNS again in the environment fixes it, because we prefer
> that value to trying the ioctl.
>
> So I don't think what you have here is wrong (though the commit message
> is a little misleading). But it seems like the original intent of our
> "unset COLUMNS" in test-lib.sh would best be fulfilled by setting it to
> a known value there (like 80), rather than unsetting it.
>
> I admit this a _bit_ of a nitpick (since as far as we know none of the
> other scripts care about the terminal width), so I'm OK with this as-is
> if you feel strongly the other way.
>
> -Peff
There has been a similar recent issue [1] on Git for Windows regarding
these settings where different terminals had different views  about the
size of the display window which resulted in incorrect out puts.

Philip

[1] https://github.com/git-for-windows/git/issues/3235