Re: [PATCH 0/3] built-in add -p: support diff-so-fancy better

From: Philippe Blain <levraiphilippeblain@gmail.com>
Date: Aug 24, 2022, 13:21 UTC
Message-ID: <41781ceb-bfad-2534-2970-c74618c93f2a@gmail.com>
In-Reply-To: <1r3pq48q-s728-8r2r-r4q3-72413r5483o1@tzk.qr>

Hi Dscho,

Le 2022-08-24 à 02:27, Johannes Schindelin a écrit :

Show 17 quoted lines

> Hi Philippe,
> 
> On Tue, 23 Aug 2022, Philippe Blain wrote:
> 
>> However, I've tried it on a more "real-life" example, and then I get:
>>
>>     error: mismatched output from interactive.diffFilter
>>     hint: Your filter must maintain a one-to-one correspondence
>>     hint: between its input and output lines.
>>
>> This is despite using "diff-so-fancy --patch" as interactive.diffFilter, which should
>> keep the number of lines the same.
> 
> Would you mind sharing the example with me?
> 
> Thanks,
> Dscho

In trying to write a reproducer, I realize that this is in fact a separate "bug". I happened to have a submodule in the repository I was testing, and it had modified content. This is what was causing the "mismatched output" error, although I'm not sure why. If I use a pathspec that does not include the submodule when invoking 'git add -p', it works correctly.

I'm a bit out of time now but I'll try to write a separate reproducer for this later today.

As for my real-life example, I noticed a little change in the output. Here is what it looks like with the Perl version:

$ git -c interactive.diffFilter="diff-so-fancy --patch" -c add.interactive.useBuiltin=false -add p ice_dyn_vp.F90

───────────────────────────────────────────────────────────────────────
modified: ice_dyn_vp.F90
───────────────────────────────────────────────────────────────────────
@ ice_dyn_vp.F90:274 @ subroutine implicit_solver (dt)
         do i = 1, nx_block
            rdg_conv (i,j,iblk) = c0
            rdg_shear(i,j,iblk) = c0
            divu (i,j,iblk) = c0
            divv (i,j,iblk) = c0
            shear(i,j,iblk) = c0
         enddo
         enddo
(1/1) Stage this hunk [y,n,q,a,d,e,?]?

The first part of the hunk header "ice_dyn_vp.F90:274" is in pink and the subroutine name is in light mauve (default diff-so-fancy colors). Here is what it looks like with your patches with the builtin version:

$ git -c interactive.diffFilter="diff-so-fancy --patch" add -p ice_dyn_vp.F90

─────────────────────────────────────────────────────────────────────── modified: ice_dyn_vp.F90 ───────────────────────────────────────────────────────────────────────

@@ -271,7 +271,7 @@ @ ice_dyn_vp.F90:274 @ subroutine implicit_solver (dt)
         do i = 1, nx_block
            rdg_conv (i,j,iblk) = c0
            rdg_shear(i,j,iblk) = c0
            divu (i,j,iblk) = c0
            divv (i,j,iblk) = c0
            shear(i,j,iblk) = c0
         enddo
         enddo
(1/1) Stage this hunk [y,n,q,a,d,e,?]? 

Notice we have the line numbers (-271,7 +271,7) in cyan, then the first part
of the hunk header modified by diff-so-fancy (ice_dyn_vp.F90:274) in pink, and
then the subroutine name (in light mauve). 

We can see the same thing with my earlier reproducer, only there is no function
matched. I really don't mind having this first part with the line numbers, I
just wanted to share my observation.

Thanks,

Philippe.