Reviewing git patches with the source file without applying the patch

Reviewing git patches with the source file without applying the patch

[husain]

Hello,

I often receive patches (files generated by 'git format-path'
command). I review these files in diff-mode. This is in most cases is
enough. But sometimes, I want to see the source code before and after
the change so that I can see the full context. I am not sure how to do
this in emacs.

diff-mode provides C-c C-c (which is diff-goto-source). This is great
improvement, but it shows the source file only, not the changes before
and after. I have to compute in my head the patch against the source
file to undrestand the change. Additionally, diff-goto-source requires
the path to the source file. I wish it would take the dir instead and it
can compute the source file on its own.

diff-mode also provides C-c C-e (which is diff-ediff-patch). This view
is what I am looking for: it provides a view when I can see the source
file before and after the change. However, diff-ediff-patch applies the
change automatically, which is not what I want to do. Additionally,
diff-ediff-patch generates .orig files which are also unwant.

Any help is appreciated.

Re: Reviewing git patches with the source file without applying the patch

[mbork]

On 2023-12-04, at 22:59, husain@alshehhi.io wrote:

> Hello,
>
> I often receive patches (files generated by 'git format-path'
> command). I review these files in diff-mode. This is in most cases is
> enough. But sometimes, I want to see the source code before and after
> the change so that I can see the full context. I am not sure how to do
> this in emacs.
>
> diff-mode provides C-c C-c (which is diff-goto-source). This is great
> improvement, but it shows the source file only, not the changes before
> and after. I have to compute in my head the patch against the source
> file to undrestand the change. Additionally, diff-goto-source requires
> the path to the source file. I wish it would take the dir instead and it
> can compute the source file on its own.
>
> diff-mode also provides C-c C-e (which is diff-ediff-patch). This view
> is what I am looking for: it provides a view when I can see the source
> file before and after the change. However, diff-ediff-patch applies the
> change automatically, which is not what I want to do. Additionally,
> diff-ediff-patch generates .orig files which are also unwant.
>
> Any help is appreciated.

That is a great question, and I don't have a 100% solution, but I would
probably use Magit, which makes it easy to discard the changes after
(temporarily) applying the patch.

Hth,

-- 
Marcin Borkowski
https://mbork.pl

Re: Reviewing git patches with the source file without applying the patch

[James Thomas]

husain@alshehhi.io wrote:

> Hello,
>
> I often receive patches (files generated by 'git format-path'
> command). I review these files in diff-mode. This is in most cases is
> enough. But sometimes, I want to see the source code before and after
> the change so that I can see the full context. I am not sure how to do
> this in emacs.
>
> diff-mode provides C-c C-c (which is diff-goto-source). This is great
> improvement, but it shows the source file only, not the changes before
> and after. I have to compute in my head the patch against the source
> file to undrestand the change. Additionally, diff-goto-source requires
> the path to the source file. I wish it would take the dir instead and it
> can compute the source file on its own.
>
> diff-mode also provides C-c C-e (which is diff-ediff-patch). This view
> is what I am looking for: it provides a view when I can see the source
> file before and after the change. However, diff-ediff-patch applies the
> change automatically, which is not what I want to do. Additionally,
> diff-ediff-patch generates .orig files which are also unwant.
>
> Any help is appreciated.

There's ediff-patch-buffer. You can also try diffing the buffer with the
file after applying the patch in diff mode, for eg, with
ediff-current-file. More: (info "(ediff) Major Entry Points")

--