Support configuration for git diff?

[rayluo]

Is your feature request related to a problem? Please describe.
There is some fancy usage for git diff. Can we have a configuration option for git diff?

Describe the solution you'd like
I apologize if there is already one of such settings available, I'm just not seeing one when examining #797. The current default config file is largely empty, by the way. Could/shall we add all available options there, while commenting out, so that users can easily find and toggle them? - Umm, this alone could be a separated feature requirement.

UPDATE 2025
Starting from upcoming lazygit 0.55, you will be able to opt in for git's existing external diff setup by configuring:

git:
  paging:
    # If true, Lazygit will use git's `diff.external` config for paging. The advantage over `externalDiffCommand` is that this can be configured per file type in .gitattributes; see https://git-scm.com/docs/gitattributes#_defining_an_external_diff_driver.
    useExternalDiffGitConfig: true

[ahmadie]

I also would like to use
git diff --ignore-space-change
which make things more readable regarding logic specially after applying some formatting

[ahmadie]

will i found workaround add following to config yaml

git:
paging:
colorArg: always -w

then replace [-w] with whatever command u like to be passed to diff command, becareful bcz colorArg is also used for that, [-w] will be passed to stash show -w and git show -w, I hope it does not cause unintended bugs

[rayluo]

Oh, since posting this enhancement request, I also asked around, got help from a StackOverflow Q&A, and finalized a self-contained solution OUTSIDE of lazygit. That means, the customized diff effect will work, regardless of whether you are using lazygit or just the good old git itself. All the pieces you will need are in my this commit (which is part of my own dotfile repo).

[jesseduffield]

Is this something we could achieve by reading the user's gitconfig? Or is the setting typically stored in some other way? If the latter I'm thinking we make it a config flag inside lazygit's own config

[rayluo]

Is this something we could achieve by reading the user's gitconfig?

My understanding is, the underlying git will already pick up the user's gitconfig, as it should. So, lazygit does NOT need to do anything in this case.

Or is the setting typically stored in some other way? If the latter I'm thinking we make it a config flag inside lazygit's own config

The proposal of this feature request was to see if lazygit would decide to pre-configure the configuration out-of-the-box.

[jesseduffield]

@ahmadie, not directly related to this issue, but we now allow the --ignore-all-space flag to git diff from inside the app with the <c-w> key

[fredcallaway]

Bumping this old issue. My use case is --word-diff which is very useful for diffing markdown and latex files (which often have full paragraphs in one line).

It would be amazing to generalize <c-w> for --ignore-all-space to allow custom toggled options on git diff!!

[rayluo]

At May 21st, 2020, I wrote,

Oh, since posting this enhancement request, I also asked around, got help from a StackOverflow Q&A, and finalized a self-contained solution OUTSIDE of lazygit. That means, the customized diff effect will work, regardless of whether you are using lazygit or just the good old git itself. All the pieces you will need are in my this commit (which is part of my own dotfile repo).

Recently, @tienlonghungson brought my attention back to this old issue. Now I realized that, the lazygit 0.20.4 released at the time when I posted the message above, was ABLE to AUTOMATICALLY utilize - or at least let the native git utilize - my settings in ~/.config/git/attributes and ~/.gitconfig. Somehow that behavior has long gone in recent versions of lazygit, even after I explicitly config lazygit 0.54.2 to use git config.

@stefanhaller , you mentioned something like "adding new keybindings for all of the new behaviors doesn't scale well" in your another comment in #3984. However, in the lazygit 0.20 era, we did not even need any keybinding for this behavior. Lazygit was capable to automatically let git just follow git's config.

Is this a regression introduced between then and now?

[stefanhaller]

@rayluo I can have a look if I find some time, but it might take a while (not the most important thing for me to spend time on right now). Feel free to ping me again if I forget.

Just to answer @fredcallaway's comment above: I understand the need, but I feel that using a custom pager that can do intra-line highlighting of changes is a better solution than word-diff. For example, look at this recent commit (the github UI does a terrible job at rendering it). With --word-diff it looks like this:

This is not great, it's still next to impossible to see what the change is.

With delta it looks like this, which I find much, much better:

[rayluo]

At May 21st, 2020, I wrote,

Oh, since posting this enhancement request, I also asked around, got help from a StackOverflow Q&A, and finalized a self-contained solution OUTSIDE of lazygit. That means, the customized diff effect will work, regardless of whether you are using lazygit or just the good old git itself. All the pieces you will need are in my this commit (which is part of my own dotfile repo).

... Now I realized that, the lazygit 0.20.4 released at the time when I posted the message above, was ABLE to AUTOMATICALLY utilize ... my settings in ~/.config/git/attributes and ~/.gitconfig. Somehow that behavior has long gone in recent versions of lazygit, even after I explicitly config lazygit 0.54.2 to use git config.

......

Is this a regression introduced between then and now?

@stefanhaller , I investigated and identified this change between lazygit 0.22.9 and 0.23.1 caused the regression. The change was used to bypass the external diff tool (because in that case it was a GUI tool bcompare). However, in my case I am using a console-based diff script, so, it is still desirable to call "git diff" without the "--no-ext-diff" flag. How shall we modify lazygit to support both legit scenarios? Shall we introduce a new param like this:

git:
  paging:
    diffArgs: --no-ext-diff

so that people can opt in? The default value shall be empty so that the default behavior follows whatever existing behavior that is already defined in git. Doesn't that make sense?

[stefanhaller]

I'm a little confused here; I'm not sure I understand why your approach worked before 0.22.9. When I just tested custom diff drivers (defined in .gitattributes), I found that they are only used when you also pass --ext-diff to the git diff (or git show) call. We didn't do this in lazygit 0.22.9, so why did this work?

(This is not very well documented in git, I feel. It isn't mentioned in the .gitattributes manpage at all, but it is mentioned in the docs for the --ext-diff option, albeit only for git log.)