Re: Combined diff format: Show all filenames by default?

From: Kang-Che Sung <explorer09@gmail.com>
Date: May 3, 2024, 22:25 UTC
Message-ID: <CADDzAfN4gXVcqUVdoA12Z+o63JbsTk8zUpNdiVFSFmTFZtrVzg@mail.gmail.com>
In-Reply-To: <xmqqjzka65ry.fsf@gitster.g>

On Sat, May 4, 2024 at 3:42 AM Junio C Hamano <gitster@pobox.com> wrote:

Show 14 quoted lines

>
> >> As the format HAS ALREADY lasted for a long time since its
> >> introduction in d8f4790e (diff-tree --cc: denser combined diff
> >> output for a merge commit., 2006-01-24), it is too late to change
> >> the default.
> >
> > I wonder what things would break if we change the default behavior of this?
>
> Human users who rarely if ever rename files will start complaining
> for wasted vertical screen real estates taken by the extra lines.
>
> Nothing is broken, and you are proposing to break things.  Be more
> gentle to existing users; "what would break if we change?" is an
> absolutely wrong attitude to approach this.

I would disagree with this.

1. Most uses of diff command are on a scrollable terminal screen (with
"less", "vi", or another text editor). It's just one line of vertical
screen taken - very subtle unless you have 4-way or more diffs. And
it's not just about renames. It's a much easier indicator that the
diff is a multi-way comparison.
2. It's a usability problem - like an Ok/Cancel dialog that took years
to realize they are badly designed. I consider the two filename only
header lines a "paper cut" usability bug. Git is able to output more
than two filenames; it just doesn't have a way to make it the default
(even as a per-user default option).

Show 11 quoted lines

>
> > Well, I won't expect the default to be changed for uses in scripts or
> > GUI frontends. I wish to change the default for interactive, terminal
> > uses, so that usability comes in "out of the box".
>
> How would a script that is running by interactive users whose
> standard input and output streams are connected to a terminal adjust
> to sudden change of the default?  The "git" invocation in such an
> environment would not be able to tell if you typed it or if you
> typed the name of the script.
>

How is it _not_ possible to tell? If user runs "git diff" from the script, then it would just print to standard output without running a "less" pager. If I want to execute a set of commands with interactivity, I would write a script and then "source my-script-name" rather than "./my-script-name", so it's still possible to tell.