Allow deactivate features by command line arguments

[przepompownia]

Example: I have activated side-by-side in ~/.gitconfig and would like to deactivate it in some usage (e.g. when run from FZF).

I did not found how to deactivate single option and to keep the rest from the config.

Some CLI-s allows deactivating their features by adding no- prefix.

[dandavison]

Hi @przepompownia, you're right that this isn't obvious currently! Try this:

[delta]
    features = normal-delta-usage

[delta "normal-delta-usage"]
    side-by-side = true

[delta "fzf"]
    side-by-side = false

Now delta --features=fzf will not have side-by-side. You can also use the env var:, e.g. DELTA_FEATURES=fzf git show.
Does that solve it for you?

To read more about delta "custom features", see https://github.com/dandavison/delta#custom-features and dandavison/magit-delta#13 (comment). You could also look at the work-in-progress user-contributed themes file, which is implemented using custom features.

Sorry, that it's a bit convoluted currently. Part of the issue is that the main rust CLI library doesn't yet support automatic negating of boolean flags via --no-* versions, see clap-rs/clap#815.

[przepompownia]

Hi @dandavison It is good to know about using custom feature. Thanks for explaining how to use it.

It works after upgrading from 0.4.4. to 0.5.1. Setting DELTA_FEATURES inside vim is enough to resolve my source problem.

[dandavison]

Great, glad that solves it for you.