Re: range-diff should suppress context-only changes?

From: Johannes Altmanninger <aclopte@gmail.com>
Date: Nov 17, 2020, 21:35 UTC
Message-ID: <20201117213551.2539438-1-aclopte@gmail.com>
In-Reply-To: <xmqqmtzvikwi.fsf@gitster.c.googlers.com>

Show 7 quoted lines

> > I wonder if it would be reasonable to suppress range-diff hunks in which
> > all of the changed lines are context lines.
> 
> Sounds like a reasonable thing to do.  As we know the shape of what
> is compared in the outer diff we should be able to accurately notice
> where hunk boundaries are and a hunk whose change is only on context
> lines.

Here are patches to ignore context-only changes in range-diff's output. I'm not completely happy with the changes, they feel a bit too hacky. Maybe someone has better ideas.

This still gives output like this one, that could be improved in future

	1:  7a3dac8 ! 1:  119bc78 Change
	    @@ some-other-file
	      7
	      8
	      9
	    - Old context line
	    + New context line

	    -## file ##
	    +## file => renamed-file ##
	     @@
	      1
	     -2

I think it should be

	1:  7a3dac8 ! 1:  119bc78 Change
	    -## file ##
	    +## file => renamed-file ##
	     @@
	      1
	     -2

I'm not sure if this is a feasible improvement.

"## <filename> ##" normally is a diff section header (hence the "@@ some-other-file" hunk above) but here the section header itself is changed..