🚀 A CLI option to disable side-by-side mode

[gotgenes]

I have side-by-side enabled in my ~/.git/config, like so

[delta]
	side-by-side = true

I noticed there is a --side-by-side option that users can pass when invoking delta from the command line, but this option does not take a value; it works by presence/absence.

I'd like to sometimes override my config setting and disable side-by-side mode, but I do not see a command line option to do this. I was expecting something like --disable-side-by-side or --no-side-by-side, or some other "layout" option, but I didn't spot one in delta --help.

Am I missing the correct option to override and disable side-by-side mode from the CLI? If not, I'd appreciate considering adding such an option.

[dandavison]

Hi @gotgenes, thanks, this request makes sense. The things that's stopped me doing it is that it would bother me to have the special "disable" flag for side-by-side but not for all the other things that can be toggled. Instead, I suggest using the DELTA_FEATURES environment variable for this (this is what I do). I just added documentation of this technique to the side-by-side section of the manual: https://dandavison.github.io/delta/side-by-side-view.html

(but take a look at the "Features" section of the manual to understand the + syntax: https://dandavison.github.io/delta/features-named-groups-of-settings.html

[dandavison]

I believe the real solution here may be this open issue in the clap repo (the Rust CLI arg parsing library): clap-rs/clap#815

[gotgenes]

@dandavison This was really helpful. I did not fully understand delta features before, and I was also unaware of the DELTA_FEATURES environment variable. This helps me. Thank you for your reply!

[gotgenes]

I just ran into this situation again today with debugloop/telescope-undo.nvim, where I wanted to disable the side-by-side, which is still set to true in my Git config.

I discovered that

1. Add support for automatic negation flags clap-rs/clap#815 is still open to this day, and
2. the Git config setting takes precedence over the DELTA_FEATURES environment variable.

My expected precedence for most CLI tools in terms of options, where a lower number means more overriding precedence, would be:

1. Values passed in as command-line options (--side-by-side)
2. Values of environment variables (DELTA_FEATURES)
3. Values from config files ($XDG_CONFIG_HOME/git/config)
4. Default values in the code of the program.

delta currently seems to have flipped the precedence of the environment variables and the config values, at the moment. Would you consider changing the order of precedence? I hope that part is under delta's control, not clap's.