From: SZEDER Gábor <szeder.dev@gmail.com>
Date: Mon, 11 Jun 2018 18:20:53 +0000 (-0700)
Subject: completion: correct zsh detection when run from git-completion.zsh
X-Git-Tag: v2.18.0-rc2~2^2
X-Git-Url: https://git.lorimer.id.au/gitweb.git/diff_plain/61d48c66ea7ef8acc0dd1114e0f79f4250aead38?hp=61d48c66ea7ef8acc0dd1114e0f79f4250aead38

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: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
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