Interesting question! I looked into it and here is what I found:
There are two separate zsh completion systems for git:
The one that ships with git (https://github.com/git/git/blob/master/contrib/completion/git-completion.zsh), which, as shown in the docs you linked, offers the completion system you have, based on any available git binaries.
The one that ships with zsh (https://github.com/zsh-users/zsh/blob/master/Completion/Unix/Command/_git), which is much more complex, as well as apparently more context-aware.
Starting a new zsh session with an empty zshrc (zsh -d -f -i) we see this:
josh% autoload -Uz compinit && compinit josh% git che<TAB> check-attr -- display gitattributes information check-ignore -- debug gitignore/exclude files check-mailmap -- show canonical names and email addresses of contacts check-ref-format -- ensure that a reference name is well formed checkout -- checkout branch or paths to working tree checkout-index -- copy files from index to working directory cherry -- find commits not merged upstream cherry-pick -- apply changes introduced by some existing commits
Then after loading the other completion system (I'll discuss how exactly to do this next):
josh% git che<TAB>
becomes
josh% git checkout
So how do we switch? The way I do it is via the OMZ plugin gitfast. I don't actually (heaven forbid) use OMZ, but just clone the plugin and source it to my fpath in zshrc with fpath=( $XDG_CONFIG_HOME/ohmyzsh/plugins/gitfast $fpath )
But it looks like a more direct way would be to follow the instructions in _git in that repo:
# The recommended way to install this script is to make a copy of it as a # file named '_git' inside any directory in your fpath. # # For example, create a directory '~/.zsh/', copy this file to '~/.zsh/_git', # and then add the following to your ~/.zshrc file: # # fpath=(~/.zsh $fpath) # # You need git's bash completion script installed. By default bash-completion's # location will be used (e.g. pkg-config --variable=completionsdir bash-completion). # # If your bash completion script is somewhere else, you can specify the # location in your ~/.zshrc: # # zstyle ':completion:*:*:git:*' script ~/.git-completion.bash
