Re: [PATCH] completion: correct zsh detection when run from git-completion.zsh (Re: [PATCH v2] completion: reduce overhead of clearing cached --options)

> From: SZEDER Gábor <szeder.dev@gmail.com>
> 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
>
> Reported-by: Rick van Hattem <wolph@wol.ph>
> Reported-by: Dave Borowitz <dborowitz@google.com>
> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
> ---
> SZEDER Gábor wrote:
>
>> Being in RC phase, I'm all for aiming for a minimal solution.
>> However, I don't think that the better fix would be erm.. any "less
>> minimal":
>
> Thanks again. May we have your sign-off?

>  contrib/completion/git-completion.bash | 5 ++++-
>  contrib/completion/git-completion.zsh  | 2 +-
>  2 files changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
> index 12814e9bbf..f4a2e6774b 100644
> --- a/contrib/completion/git-completion.bash
> +++ b/contrib/completion/git-completion.bash
> @@ -3223,7 +3223,10 @@ __gitk_main ()
>         __git_complete_revlist
>  }
>
> -if [[ -n ${ZSH_VERSION-} ]]; then
> +if [[ -n ${ZSH_VERSION-} ]] &&
> +   # Don't define these functions when sourced from 'git-completion.zsh',
> +   # it has its own implementations.
> +   [[ -z ${GIT_SOURCING_ZSH_COMPLETION-} ]]; then
>         echo "WARNING: this script is deprecated, please see git-completion.zsh" 1>&2
>
>         autoload -U +X compinit && compinit
> diff --git a/contrib/completion/git-completion.zsh b/contrib/completion/git-completion.zsh
> index 53cb0f934f..049d6b80f6 100644
> --- a/contrib/completion/git-completion.zsh
> +++ b/contrib/completion/git-completion.zsh
> @@ -39,7 +39,7 @@ if [ -z "$script" ]; then
>                 test -f $e && script="$e" && break
>         done
>  fi
> -ZSH_VERSION='' . "$script"
> +GIT_SOURCING_ZSH_COMPLETION=y . "$script"
>
>  __gitcomp ()
>  {
> --
> 2.18.0.rc1.242.g61856ae69a
>