`delta` pager option `--detect-dark-light` not working.

[andradei]

Describe the bug
Using delta as a pager, it will default to dark theme unless using delta --light,
and event --detect-dark-light always is ignored. Also, delta auto-detects dark/light terminal colors by default and omitting --light/--dark from lazygit config.yml still defaults to dark theme pager.

To Reproduce

lazygit/config.yml

gui:
  nerdFontsVersion: "3"
git:
  paging:
    colorArg: always
    pager: delta --detect-dark-light always --paging never

gitconfig

; ...
[delta]
    navigate = true
    line-numbers = true
    side-by-side = true
    whitespace-error-style = 22 reverse
    ; could also have `detect-dark-light = always` and lazygit is not picking it

Expected behavior
lazygit uses the delta behavior of auto-detecting dark/light theme.

Screenshots

Notice dark theme on the pager area of lazygit

Version info:

❯ lazygit --version
commit=v0.50.0, build date=2025-05-04T07:59:01Z, build source=binaryRelease, version=0.50.0, os=linux, arch=amd64, git version=2.49.0
_Run `git --version` and paste the result here_

❯ git version
git version 2.49.0

[pricci1]

+1 It would be great to support delta --detect-dark-light=always

Header
Delta's dark on Kitty's light:
Delta's light on Kitty's dark:
Delta's light on Kitty's light:

For now I just settle with delta --light, that is usable, tough a bit bright when in dark theme

[dwt]

For what it's worth, it is possible to detect light or dark mode by asking the system, e.g. defaults read -g AppleInterfaceStyle which returns either nothing (light mode) or Dark for dark mode. Alternatively this AppleScript Snippet works too:

❯ osascript -e 'tell application "System Events" to tell appearance preferences to get dark mode' | grep -q true && echo Dark || echo Light
Dark

~  
❯ osascript -e 'tell application "System Events" to tell appearance preferences to get dark mode' | grep -q true && echo Dark || echo Light
Light

[dwt]

I see the same behavior on MacOS Tahoe with both the builtin Terminal, as well as the Terminal used in Zed

❯ sw_vers 
ProductName:		macOS
ProductVersion:		26.1
BuildVersion:		25B78
❯ delta --version
delta 0.18.2
❯ lazygit --version
commit=, build date=, build source=nix, version=0.56.0, os=darwin, arch=arm64, git version=2.51.0

[stefanhaller]

There's a workaround for supporting automatic light/dark switching with delta on macOS: #4366 (comment)

Building support for this into lazygit is likely a lot of work, and I'm not really sure it's worth it. But maybe that's because I don't understand why anybody would want to switch dark/light automatically; I prefer my terminal (and IDE) to be always dark. Personal preference, I know.

[patrik-csak]

@stefanhaller To answer that question for my use case, I use DarkModeBuddy to automatically switch between dark and light mode based on ambient light. This means that I switch between dark and light mode from a few times a day to a few times an hour.

[lmdevv]

+1

When I try git diff where git is configured to use delta pager, it works on both light and dark mode, but when checking diff in lazygit it defaults to dark mode.

[Lcchy]

FYI the underlying issue is that the pagers get executed in a PTY that does not let OSC messages through.

Ref:
#3419
https://github.com/jesseduffield/lazygit/blob/master/pkg/gui/pty.go