autocomplete for git in bash

#
# bash completion support for core Git.
#
# Copyright (C) 2006,2007 Shawn O. Pearce <[email protected]>
# Conceptually based on gitcompletion (http://gitweb.hawaga.org.uk/).
# Distributed under the GNU General Public License, version 2.0.
#
# The contained completion routines provide support for completing:
#
#    *) local and remote branch names
#    *) local and remote tag names
#    *) .git/remotes file names
#    *) git 'subcommands'
#    *) tree paths within 'ref:path/to/file' expressions
#    *) common --long-options
#
# To use these routines:
#
#    1) Copy this file to somewhere (e.g. ~/.git-completion.sh).
#    2) Added the following line to your .bashrc:
#        source ~/.git-completion.sh
#
#    3) You may want to make sure the git executable is available
#       in your PATH before this script is sourced, as some caching
#       is performed while the script loads.  If git isn't found
#       at source time then all lookups will be done on demand,
#       which may be slightly slower.
#
#    4) Consider changing your PS1 to also show the current branch:
#        PS1='[\u@\h \W$(__git_ps1 " (%s)")]\$ '
#
#       The argument to __git_ps1 will be displayed only if you
#       are currently in a git repository.  The %s token will be
#       the name of the current branch.
#
# To submit patches:
#
#    *) Read Documentation/SubmittingPatches
#    *) Send all patches to the current maintainer:
#
#       "Shawn O. Pearce" <[email protected]>
#
#    *) Always CC the Git mailing list:
#
#       [email protected]
#

case "$COMP_WORDBREAKS" in
*:*) : great ;;
*)   COMP_WORDBREAKS="$COMP_WORDBREAKS:"
esac

__gitdir ()
{
	if [ -z "$1" ]; then
		if [ -n "$__git_dir" ]; then
			echo "$__git_dir"
		elif [ -d .git ]; then
			echo .git
		else
			git rev-parse --git-dir 2>/dev/null
		fi
	elif [ -d "$1/.git" ]; then
		echo "$1/.git"
	else
		echo "$1"
	fi
}

__git_ps1 ()
{
	local g="$(git rev-parse --git-dir 2>/dev/null)"
	if [ -n "$g" ]; then
		local r
		local b
		if [ -d "$g/rebase-apply" ]
		then
			if test -f "$g/rebase-apply/rebasing"
			then
				r="|REBASE"
			elif test -f "$g/rebase-apply/applying"
			then
				r="|AM"
			else
				r="|AM/REBASE"
			fi
			b="$(git symbolic-ref HEAD 2>/dev/null)"
		elif [ -f "$g/rebase-merge/interactive" ]
		then
			r="|REBASE-i"
			b="$(cat "$g/rebase-merge/head-name")"
		elif [ -d "$g/rebase-merge" ]
		then
			r="|REBASE-m"
			b="$(cat "$g/rebase-merge/head-name")"
		elif [ -f "$g/MERGE_HEAD" ]
		then
			r="|MERGING"
			b="$(git symbolic-ref HEAD 2>/dev/null)"
		else
			if [ -f "$g/BISECT_LOG" ]
			then
				r="|BISECTING"
			fi
			if ! b="$(git symbolic-ref HEAD 2>/dev/null)"
			then
				if ! b="$(git describe --exact-match HEAD 2>/dev/null)"
				then
					b="$(cut -c1-7 "$g/HEAD")..."
				fi
			fi
		fi

		if [ -n "$1" ]; then
			printf "$1" "${b##refs/heads/}$r"
		else
			printf " (%s)" "${b##refs/heads/}$r"
		fi
	fi
}

__gitcomp_1 ()
{
	local c IFS=' '$'\t'$'\n'
	for c in $1; do
		case "$c$2" in
		--*=*) printf %s$'\n' "$c$2" ;;
		*.)    printf %s$'\n' "$c$2" ;;
		*)     printf %s$'\n' "$c$2 " ;;
		esac
	done
}

__gitcomp ()
{
	local cur="${COMP_WORDS[COMP_CWORD]}"
	if [ $# -gt 2 ]; then
		cur="$3"
	fi
	case "$cur" in
	--*=)
		COMPREPLY=()
		;;
	*)
		local IFS=$'\n'
		COMPREPLY=($(compgen -P "$2" \
			-W "$(__gitcomp_1 "$1" "$4")" \
			-- "$cur"))
		;;
	esac
}

__git_heads ()
{
	local cmd i is_hash=y dir="$(__gitdir "$1")"
	if [ -d "$dir" ]; then
		git --git-dir="$dir" for-each-ref --format='%(refname:short)' \
			refs/heads
		return
	fi
	for i in $(git ls-remote "$1" 2>/dev/null); do
		case "$is_hash,$i" in
		y,*) is_hash=n ;;
		n,*^{}) is_hash=y ;;
		n,refs/heads/*) is_hash=y; echo "${i#refs/heads/}" ;;
		n,*) is_hash=y; echo "$i" ;;
		esac
	done
}

__git_tags ()
{
	local cmd i is_hash=y dir="$(__gitdir "$1")"
	if [ -d "$dir" ]; then
		git --git-dir="$dir" for-each-ref --format='%(refname:short)' \
			refs/tags
		return
	fi
	for i in $(git ls-remote "$1" 2>/dev/null); do
		case "$is_hash,$i" in
		y,*) is_hash=n ;;
		n,*^{}) is_hash=y ;;
		n,refs/tags/*) is_hash=y; echo "${i#refs/tags/}" ;;
		n,*) is_hash=y; echo "$i" ;;
		esac
	done
}

__git_refs ()
{
	local i is_hash=y dir="$(__gitdir "$1")"
	local cur="${COMP_WORDS[COMP_CWORD]}" format refs
	if [ -d "$dir" ]; then
		case "$cur" in
		refs|refs/*)
			format="refname"
			refs="${cur%/*}"
			;;
		*)
			if [ -e "$dir/HEAD" ]; then echo HEAD; fi
			format="refname:short"
			refs="refs/tags refs/heads refs/remotes"
			;;
		esac
		git --git-dir="$dir" for-each-ref --format="%($format)" \
			$refs
		return
	fi
	for i in $(git ls-remote "$dir" 2>/dev/null); do
		case "$is_hash,$i" in
		y,*) is_hash=n ;;
		n,*^{}) is_hash=y ;;
		n,refs/tags/*) is_hash=y; echo "${i#refs/tags/}" ;;
		n,refs/heads/*) is_hash=y; echo "${i#refs/heads/}" ;;
		n,refs/remotes/*) is_hash=y; echo "${i#refs/remotes/}" ;;
		n,*) is_hash=y; echo "$i" ;;
		esac
	done
}

__git_refs2 ()
{
	local i
	for i in $(__git_refs "$1"); do
		echo "$i:$i"
	done
}

__git_refs_remotes ()
{
	local cmd i is_hash=y
	for i in $(git ls-remote "$1" 2>/dev/null); do
		case "$is_hash,$i" in
		n,refs/heads/*)
			is_hash=y
			echo "$i:refs/remotes/$1/${i#refs/heads/}"
			;;
		y,*) is_hash=n ;;
		n,*^{}) is_hash=y ;;
		n,refs/tags/*) is_hash=y;;
		n,*) is_hash=y; ;;
		esac
	done
}

__git_remotes ()
{
	local i ngoff IFS=$'\n' d="$(__gitdir)"
	shopt -q nullglob || ngoff=1
	shopt -s nullglob
	for i in "$d/remotes"/*; do
		echo ${i#$d/remotes/}
	done
	[ "$ngoff" ] && shopt -u nullglob
	for i in $(git --git-dir="$d" config --list); do
		case "$i" in
		remote.*.url=*)
			i="${i#remote.}"
			echo "${i/.url=*/}"
			;;
		esac
	done
}

__git_merge_strategies ()
{
	if [ -n "$__git_merge_strategylist" ]; then
		echo "$__git_merge_strategylist"
		return
	fi
	git merge -s help 2>&1 |
	sed -n -e '/[Aa]vailable strategies are: /,/^$/{
		s/\.$//
		s/.*://
		s/^[ 	]*//
		s/[ 	]*$//
		p
	}'
}
__git_merge_strategylist=
__git_merge_strategylist=$(__git_merge_strategies 2>/dev/null)

__git_complete_file ()
{
	local pfx ls ref cur="${COMP_WORDS[COMP_CWORD]}"
	case "$cur" in
	?*:*)
		ref="${cur%%:*}"
		cur="${cur#*:}"
		case "$cur" in
		?*/*)
			pfx="${cur%/*}"
			cur="${cur##*/}"
			ls="$ref:$pfx"
			pfx="$pfx/"
			;;
		*)
			ls="$ref"
			;;
	    esac

		case "$COMP_WORDBREAKS" in
		*:*) : great ;;
		*)   pfx="$ref:$pfx" ;;
		esac

		local IFS=$'\n'
		COMPREPLY=($(compgen -P "$pfx" \
			-W "$(git --git-dir="$(__gitdir)" ls-tree "$ls" \
				| sed '/^100... blob /{
				           s,^.*	,,
				           s,$, ,
				       }
				       /^120000 blob /{
				           s,^.*	,,
				           s,$, ,
				       }
				       /^040000 tree /{
				           s,^.*	,,
				           s,$,/,
				       }
				       s/^.*	//')" \
			-- "$cur"))
		;;
	*)
		__gitcomp "$(__git_refs)"
		;;
	esac
}

__git_complete_revlist ()
{
	local pfx cur="${COMP_WORDS[COMP_CWORD]}"
	case "$cur" in
	*...*)
		pfx="${cur%...*}..."
		cur="${cur#*...}"
		__gitcomp "$(__git_refs)" "$pfx" "$cur"
		;;
	*..*)
		pfx="${cur%..*}.."
		cur="${cur#*..}"
		__gitcomp "$(__git_refs)" "$pfx" "$cur"
		;;
	*)
		__gitcomp "$(__git_refs)"
		;;
	esac
}

__git_all_commands ()
{
	if [ -n "$__git_all_commandlist" ]; then
		echo "$__git_all_commandlist"
		return
	fi
	local i IFS=" "$'\n'
	for i in $(git help -a|egrep '^ ')
	do
		case $i in
		*--*)             : helper pattern;;
		*) echo $i;;
		esac
	done
}
__git_all_commandlist=
__git_all_commandlist="$(__git_all_commands 2>/dev/null)"

__git_porcelain_commands ()
{
	if [ -n "$__git_porcelain_commandlist" ]; then
		echo "$__git_porcelain_commandlist"
		return
	fi
	local i IFS=" "$'\n'
	for i in "help" $(__git_all_commands)
	do
		case $i in
		*--*)             : helper pattern;;
		applymbox)        : ask gittus;;
		applypatch)       : ask gittus;;
		archimport)       : import;;
		cat-file)         : plumbing;;
		check-attr)       : plumbing;;
		check-ref-format) : plumbing;;
		checkout-index)   : plumbing;;
		commit-tree)      : plumbing;;
		count-objects)    : infrequent;;
		cvsexportcommit)  : export;;
		cvsimport)        : import;;
		cvsserver)        : daemon;;
		daemon)           : daemon;;
		diff-files)       : plumbing;;
		diff-index)       : plumbing;;
		diff-tree)        : plumbing;;
		fast-import)      : import;;
		fast-export)      : export;;
		fsck-objects)     : plumbing;;
		fetch-pack)       : plumbing;;
		fmt-merge-msg)    : plumbing;;
		for-each-ref)     : plumbing;;
		hash-object)      : plumbing;;
		http-*)           : transport;;
		index-pack)       : plumbing;;
		init-db)          : deprecated;;
		local-fetch)      : plumbing;;
		lost-found)       : infrequent;;
		ls-files)         : plumbing;;
		ls-remote)        : plumbing;;
		ls-tree)          : plumbing;;
		mailinfo)         : plumbing;;
		mailsplit)