Request: git add --interactive: split hunk: When can't split further, split on empty lines

> When adding interactively, 's' can be used to split the current hunk.
> Once it gets down to where 's' reports "Sorry, cannot split this
> hunk", it could be useful if it would then start splitting based on
> empty lines, probably leaving empty lines at the top of the split
> hunks.  It certainly wouldn't be perfect, and might create many hunks,
> but it would be a nice alternative to manually editing the hunk.
> Certainly someone could still manually edit the hunk if they didn't
> want to use it in a particular situation.

> Hi James,
>
> On Wed, 29 May 2019, James Harvey wrote:
>
>> When adding interactively, 's' can be used to split the current hunk.
>> Once it gets down to where 's' reports "Sorry, cannot split this
>> hunk", it could be useful if it would then start splitting based on
>> empty lines, probably leaving empty lines at the top of the split
>> hunks.  It certainly wouldn't be perfect, and might create many hunks,

>> but it would be a nice alternative to manually editing the hunk.
>> Certainly someone could still manually edit the hunk if they didn't
>> want to use it in a particular situation.
> While a neat idea from the users' perspective, I think that it is
> technically a bit challenging, as you then have a problem to coalesce the
> patches appropriately.
>
> The thing with the splitting at context lines is that you have a much
> easier time to merge individual split-hunks into a "coalesced" hunk
> because the context lines stay context lines.
>
> Having said that, there was a patch series recently to add the ability to
> stage individual lines,

> and I think that your feature request could be
> implemented on top of that.
>
> In the meantime, an Outreachy intern and I worked on turning `git add -i`
> into a built-in (it was written in Perl, and the built-in is written in
> portable C instead), and I *think* that the plan with the patch series to
> stage individual lines was to re-implement it on top of the built-in patch
> series.
>
> Would you be interested in participating in that project?
>
> Ciao,
> Johannes

> On 30/05/2019 15:53, Johannes Schindelin wrote:
> >
> > Having said that, there was a patch series recently to add the ability to
> > stage individual lines,
>
> I believe that the git-gui (in tk/tcl, but using git commands) was
> already able to stage individual/selected lines, so there may be some
> ideas from there.

> Hi Philip,
>
> On Thu, 30 May 2019, Philip Oakley wrote:
>
>> On 30/05/2019 15:53, Johannes Schindelin wrote:
>>> Having said that, there was a patch series recently to add the ability to
>>> stage individual lines,
>> I believe that the git-gui (in tk/tcl, but using git commands) was
>> already able to stage individual/selected lines, so there may be some
>> ideas from there.
> Sadly, no.
>
> There is one very big difference between Git GUI and `git add -p`: when
> you stage a line in Git GUI, it is staged *immediately*.
>
> When you stage a single line in the Git GUI, the diff you see in the
> window is reloaded. That is quite slow in the long run, and no fun.
>
> In contrast, `git add -p` does not stage *anything* until you're done
> selecting what you want to stage.
>
> Therefore, `git add -p` does have to do things quite a bit differently, as
> it will have to eventually build a single diff that is applied in one fell
> swoop, no matter how many lines you select individually.
>
> And naturally, there is also the difference between the user interfaces:
> while you can ask the user to select (part of) the line to stage in Git
> GUI via the mouse, that is not at all an option in `git add -p`.
>
> Likewise, the very convenient option to navigate via regular expressions
> in `git add -p` is not available in Git GUI at all.
>
> In short: I think that it makes more sense to come up with a design
> specific to `git add -p` and not get distracted by Tcl code that works
> quite differently.
>
> Ciao,
> Dscho