I have been using includeIf in my .gitconfig for years, usually to
separate out my personal git config on my work machine. Typically the only
directory I have checked out that I am regularly committing to is my
dotfiles repo, but it can happen.
So anyway, usually it looks something like this:
# wrong!
[include]
path = ~/.gitconfig-default
[includeIf "gitdir:~/code/winks"]
path = ~/.gitconfig-personal
[includeIf "gitdir:~/code/dotfiles"]
path = ~/.gitconfig-personal
so it would use company@example.org by default, but use
personal@example.org in those 2 folders.
Apparently at some point I checked in a wrong version to my dotfiles and because I'm not usually running that on my own machines I missed the error.
This is how it actually works:
# correct
[include]
path = ~/.gitconfig-default
[includeIf "gitdir:~/code/winks/"]
path = ~/.gitconfig-personal
[includeIf "gitdir:~/code/dotfiles/.git"]
path = ~/.gitconfig-personal
Yes, the trailing slash is important. Doh.
You can also leave off the .git, but maybe that makes it clearer that this
is a single repo, while the first example matches every subdir as well.
Source: man page
Addendum: Apparently you can also solve the "different keys for the same host, e.g. github.com" problem with includes:
https://stevenharman.net/configure-ssh-keys-for-multiple-github-accounts