On Mon, Jun 11, 2018 at 8:20 PM, Jonathan Nieder <jrnieder@xxxxxxxxx> wrote:
> From: SZEDER Gábor <szeder.dev@xxxxxxxxx>
> Subject: completion: correct zsh detection when run from git-completion.zsh
>
> v2.18.0-rc0~90^2 (completion: reduce overhead of clearing cached
> --options, 2018-04-18) worked around a bug in bash's "set" builtin on
> MacOS by using compgen instead. It was careful to avoid breaking zsh
> by guarding this workaround with
>
> if [[ -n ${ZSH_VERSION-}} ]]
>
> Alas, this interacts poorly with git-completion.zsh's bash emulation:
>
> ZSH_VERSION='' . "$script"
>
> Correct it by instead using a new GIT_SOURCING_ZSH_COMPLETION shell
> variable to detect whether git-completion.bash is being sourced from
> git-completion.zsh. This way, the zsh variant is used both when run
> from zsh directly and when run via git-completion.zsh.
>
> Reproduction recipe:
>
> 1. cd git/contrib/completion && cp git-completion.zsh _git
> 2. Put the following in a new ~/.zshrc file:
>
> autoload -U compinit; compinit
> autoload -U bashcompinit; bashcompinit
> fpath=(~/src/git/contrib/completion $fpath)
>
> 3. Open zsh and "git <TAB>".
>
> With this patch:
> Triggers nice git-completion.bash based tab completion
>
> Without:
> contrib/completion/git-completion.bash:354: read-only variable: QISUFFIX
> zsh:12: command not found: ___main
> zsh:15: _default: function definition file not found
> _dispatch:70: bad math expression: operand expected at `/usr/bin/g...'
> Segmentation fault
Btw, even if ZSH were not to segfault, the resulting shell would be
next to useless. The thing is that 'compgen -v foo' is supposed to
list only variable names starting with 'foo', at least that's what it
does under Bash. In ZSH's Bash emulation, however, it lists _all_
variable names, including such fundamental env vars like PATH, HOME,
and IFS. So when ZSH took the wrong if branch and run that
unset $(compgen -v __gitcomp_builtin_)
then it would unset PATH and everything else as well.
