bug#18128: Diff-mode doesn't refine hunks automatically

bug#18128: Diff-mode doesn't refine hunks automatically

[Paul Pogonyshev]

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Diff-mode should just refine hunks automatically when visiting a buffer. If
it is a performance concern, there should be some customization option for
it and/or this could be done lazily.

Chunk refining is just too useful to not have.

Paul

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bug#18128: Diff-mode doesn't refine hunks automatically

[Eli Zaretskii]

> Date: Mon, 28 Jul 2014 15:59:12 +0200
> From: Paul Pogonyshev <pogonyshev@gmail.com>
> 
> Diff-mode should just refine hunks automatically when visiting a buffer. If
> it is a performance concern, there should be some customization option for
> it and/or this could be done lazily.
> 
> Chunk refining is just too useful to not have.

Why isn't diff-auto-refine-mode enough?

bug#18128: Diff-mode doesn't refine hunks automatically

[Paul Pogonyshev]

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It is enough. Then please add a reference to it to documentation of
diff-refine-hunk, I wasn't even aware of that mode.

Paul


On 28 July 2014 16:28, Eli Zaretskii <eliz@gnu.org> wrote:

> > Date: Mon, 28 Jul 2014 15:59:12 +0200
> > From: Paul Pogonyshev <pogonyshev@gmail.com>
> >
> > Diff-mode should just refine hunks automatically when visiting a buffer.
> If
> > it is a performance concern, there should be some customization option
> for
> > it and/or this could be done lazily.
> >
> > Chunk refining is just too useful to not have.
>
> Why isn't diff-auto-refine-mode enough?
>

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bug#18128: Diff-mode doesn't refine hunks automatically

[Eli Zaretskii]

> Date: Mon, 28 Jul 2014 16:39:56 +0200
> From: Paul Pogonyshev <pogonyshev@gmail.com>
> Cc: 18128@debbugs.gnu.org
> 
> It is enough. Then please add a reference to it to documentation of
> diff-refine-hunk, I wasn't even aware of that mode.

It is currently mentioned there as follows:

   `M-n'
	Move to the next hunk-start (`diff-hunk-next').

	This command has a side effect: it "refines" the hunk you move to,
	highlighting its changes with better granularity.  To disable this
	feature, type `M-x diff-auto-refine-mode' to toggle off the minor
	mode Diff Auto-Refine mode.  To disable Diff Auto Refine mode by
	default, add this to your init file (*note Hooks::):

	     (add-hook 'diff-mode-hook
		       (lambda () (diff-auto-refine-mode -1)))

If you think this is not enough, please tell what else would you like
to see there about this minor mode.

bug#18128: Diff-mode doesn't refine hunks automatically

[Paul Pogonyshev]

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Actually, it seems it is not enough. My usecase: I open a fairly large diff
file with many changes like

-bla bla bla a long line were some word was changed or maybe two
+bla bla bla a long line where some word was changed or maybe two

I want to be able to immediately see the changes, without reading whole
lines and certainly without visiting the hunks. When Emacs highlights the
change (there is only one above), I see it right away. Otherwise I have to
scan the lines with my eyes, which is tedious and error-prone. Of course I
can also hit C-c C-b on each hunk, but it feels like some sort of work I'd
prefer Emacs do for me.

Paul


On 28 July 2014 16:39, Paul Pogonyshev <pogonyshev@gmail.com> wrote:

> It is enough. Then please add a reference to it to documentation of
> diff-refine-hunk, I wasn't even aware of that mode.
>
> Paul
>
>
> On 28 July 2014 16:28, Eli Zaretskii <eliz@gnu.org> wrote:
>
>> > Date: Mon, 28 Jul 2014 15:59:12 +0200
>> > From: Paul Pogonyshev <pogonyshev@gmail.com>
>> >
>> > Diff-mode should just refine hunks automatically when visiting a
>> buffer. If
>> > it is a performance concern, there should be some customization option
>> for
>> > it and/or this could be done lazily.
>> >
>> > Chunk refining is just too useful to not have.
>>
>> Why isn't diff-auto-refine-mode enough?
>>
>
>

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bug#18128: Diff-mode doesn't refine hunks automatically

[Paul Pogonyshev]

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I'd like hunks to be refined regardless of the way I move around the file.
E.g. if I chose to page-up through uninteresting parts of the diff,
auto-refinining shouldn't stop.

Paul


On 28 July 2014 16:44, Eli Zaretskii <eliz@gnu.org> wrote:

> > Date: Mon, 28 Jul 2014 16:39:56 +0200
> > From: Paul Pogonyshev <pogonyshev@gmail.com>
> > Cc: 18128@debbugs.gnu.org
> >
> > It is enough. Then please add a reference to it to documentation of
> > diff-refine-hunk, I wasn't even aware of that mode.
>
> It is currently mentioned there as follows:
>
>    `M-n'
>         Move to the next hunk-start (`diff-hunk-next').
>
>         This command has a side effect: it "refines" the hunk you move to,
>         highlighting its changes with better granularity.  To disable this
>         feature, type `M-x diff-auto-refine-mode' to toggle off the minor
>         mode Diff Auto-Refine mode.  To disable Diff Auto Refine mode by
>         default, add this to your init file (*note Hooks::):
>
>              (add-hook 'diff-mode-hook
>                        (lambda () (diff-auto-refine-mode -1)))
>
> If you think this is not enough, please tell what else would you like
> to see there about this minor mode.
>

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bug#18128: Diff-mode doesn't refine hunks automatically

[Stefan Monnier]

> Diff-mode should just refine hunks automatically when visiting a buffer. If
> it is a performance concern, there should be some customization option for
> it and/or this could be done lazily.

Agreed, it should be done "as part of font-locking".


        Stefan

bug#18128: Should be done as part of the font-lock

[Hong Xu]

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I agree that this should be done as part of the font-lock. This issue
not only causes inconvenience, but also causes bug #21990, which does
not allow htmlfontify to correctly display the highlighting.

Hong


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bug#18128: Should be done as part of the font-lock

[Hong Xu]

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I currently use the following to do auto refining: (modified from
http://emacs.stackexchange.com/a/28321/2755 )

    (defun my-diff-refine-all ()
    "Refine all diffs."
    (interactive)
    (save-excursion
        (goto-char (point-min))
        (ignore-errors
            (diff-beginning-of-hunk t))
        (ignore-errors
            (while (not (eobp))
            (diff-refine-hunk)
            (diff-hunk-next)))))
    (defun my-diff-hunks-highlight-all ()
    "Highlight all hunks in diff-mode."
    (add-hook 'font-lock-mode-hook #'my-diff-refine-all t t))
    (add-hook 'diff-mode-hook 'my-diff-hunks-highlight-all)

Not sure whether it is possible to merge into Emacs after some
adjustment.

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bug#18128: Diff-mode doesn't refine hunks automatically

[npostavs]

Paul Pogonyshev <pogonyshev@gmail.com> writes:

> Diff-mode should just refine hunks automatically when visiting a
> buffer. If it is a performance concern, there should be some
> customization option for it and/or this could be done lazily.
>

A patch was recently added to magit that let-binds
write-region-inhibit-fsync around the call to diff-refine-hunk, this was
reported to make a significant improvement in speed when refining all
hunks in a diff.  We should do the same for smerge-refine-subst (or is
it possible to do this automatically for all temp files?) before
extending diff refinement over the whole buffer.

https://patch-diff.githubusercontent.com/raw/magit/magit/pull/2834.patch