Re: git diff: print hunk numbers?

From: Aleksey Midenkov <midenok@gmail.com>
Date: Sep 9, 2021, 21:31 UTC
Message-ID: <CAF8BazDyALuPtazZ-H5HnsR2HweVsc6yZPbObSDG+y-m+cUF3Q@mail.gmail.com>
In-Reply-To: <CAF8BazB+RLrzD7eO_fmsUbLY0DbqFeum+eMeY1hdZSAnWTxn4A@mail.gmail.com>

On Thu, Sep 9, 2021 at 6:45 PM Aleksey Midenkov <midenok@gmail.com> wrote:

Show 49 quoted lines

>
> On Thu, Sep 9, 2021 at 12:39 AM Jeff King <peff@peff.net> wrote:
> >
> > On Wed, Sep 08, 2021 at 11:40:20PM +0300, Aleksey Midenkov wrote:
> >
> > > Is that possible/how to print hunk numbers with git diff?
> > >
> > > F.ex. instead of:
> > >
> > > @@ -106,7 +110,6 @@ while ($r < $statement_count)
> > > ...
> > >
> > > To print something like:
> > >
> > > @@ -106,7 +110,6 @@ 4 @@ while ($r < $statement_count)
> > > ...
> > >
> > > filterdiff uses hunk numbers intensively. Work with line-number ranges
> > > is not so effective.
> >
> > No, Git doesn't know how to do any annotations on hunk lines (aside from
> > finding and reporting the funcname lines from the source). So you'd have
> > to post-process it, like:
> >
> >   git diff ... |
> >   perl -pe 's/^@@.*?@@/join(" ", $&, ++$i, "@@")/e'
> >
> > but I'm not sure if that's quite what you're after. If you're using
> > filterdiff to pick out hunks, then piping through "filterdiff
> > --annotate" does something similar.
> >
> > If you want to post-process your diffs all the time, you can do
> > something like:
> >
> >   git config pager.color false
> >   git config pager.diff 'filterdiff --annotate | less'
> >
>
> Thanks!
>
>  git config pager.color false
>  git config pager.diff 'filterdiff --annotate | colordiff | less -FRX'
>  git config pager.show 'filterdiff --annotate | colordiff | less -FRX'
>
> did the job for me.
>
> > to show the annotations anytime the output is going to a terminal.
> > Though sadly filterdiff does not handle the colors; other
> > post-processors like diff-highlight parse around them.

What's more sadly filterdiff --annotate does not handle non-diff output, so --stat option does not work! I should now detect whether it is diff by reading the first line then return it to the pipe and run filterdiff conditionally. That is all mess and the testing construct just doesn't work (not sure if the command is bash-friendly at all):

git config pager.show 'IFS= read -r l; echo $l $l $l; cat'

So I can only overcome this by introducing different command through alias `s` and assign custom pager to `s`:

git config pager.color true git config --unset pager.show git config pager.s "sed 's/\x1b\[[0-9;]*m//g'|filterdiff --annotate|colordiff|less -FRX"

sed will bite out ANSI escape sequences.

Show 19 quoted lines

> >
> > And finally, if your ultimate goal is to use filterdiff to pick out
> > hunks, you might find using Git's picking tools like "checkout -p"
> > easier. Even if you are starting with an actual patch, you can apply it
> > and then pick out bits, like:
> >
> >   git checkout --detach ;# temporary head for applying patch
> >   git apply </path/to/patch
> >   git commit -m "temporary commit for patch"
> >   git checkout - ;# back to the original branch
> >   git checkout -p HEAD@{1} ;# now selectively grab parts
> >
> > Of course that only helps if the patch actually applies. If your goal is
> > to filter out hunks that don't apply, it won't help. :)
> >
> > -Peff
>
> --
> @midenok

-- 
@midenok