Handle repos that use 'main' as the main branch

[PGScully]

Is your feature request related to a problem? Please describe.

GitHub and git are now using 'main' instead of 'master' for the default branch name. lazygit only considers 'master', and colors 'main' as a branch instead of the default branch.

Describe the solution you'd like

git can now be configured to use any name as the default branch with the following config snippet:

[init]
        defaultBranch = main

lazygit should use the defaultBranch option for programatically determine the branch to color as master, and fall back to 'master' or 'main' if it's not present.

Describe alternatives you've considered

Additional context

https://github.com/github/renaming

git 2.28 introduced the defaultBranch config option: https://github.blog/2020-07-27-highlights-from-git-2-28/#introducing-init-defaultbranch

[jesseduffield]

Alas, the defaultBranch config option only applies to when we're creating a new repo, not when we're dealing with an existing one. We'll need to wait and see if git makes this easier for us

[PGScully]

I think the "99% solution" is:

• if master exists and main does not, use master
• if main exists, and master does not, use main

What to do if both or neither of them exist is the challenging UX corner case.

[jesseduffield]

@PGScully I agree. In the case where both exist I would use master. I feel like in repos where main has been opted for, it's less likely that we'll see a master branch compared to vice versa.

[PGScully]

Interestingly, Oh My Zsh's git plugin git_main_branch() function tests for main, then trunk, and if neither is found uses master.

https://github.com/ohmyzsh/ohmyzsh/blob/master/plugins/git/git.plugin.zsh#L32

[mark2185]

Resolved by #2020 .

[Ryooooooga]

@mark2185 This issue and #2020 are unrelated.

[jesseduffield]

Yep, this issue is about colouring commits based on whether they're included in the main branch, whether that's master or main. This is a harder problem to solve (efficiently) without adding a per-repo config option, given that git has no way to tell us what the main branch is.

[mark2185]

Ah, my bad, I only checked the coloring of the branch in the branches panel. Sorry for the noise!