KSH support for git-prompt

gistfile1.ksh

# ksh git prompt support
#
# Copyright (C) 2006,2007 Shawn O. Pearce <[email protected]>
# Distributed under the GNU General Public License, version 2.0.
#
# This script allows you to see repository status in your prompt.
#
# To enable:
#
#    1) Copy this file to somewhere (e.g. ~/.git-prompt.sh).
#    2) Add the following line to your .bashrc/.zshrc:
#        source ~/.git-prompt.sh
#    3a) Change your PS1 to call __git_ps1 as
#        command-substitution:
#        Bash: PS1='[\u@\h \W$(__git_ps1 " (%s)")]\$ '
#        ZSH:  setopt PROMPT_SUBST ; PS1='[%n@%m %c$(__git_ps1 " (%s)")]\$ '
#        the optional argument will be used as format string.
#    3b) Alternatively, for a slightly faster prompt, __git_ps1 can
#        be used for PROMPT_COMMAND in Bash or for precmd() in Zsh
#        with two parameters, <pre> and <post>, which are strings
#        you would put in $PS1 before and after the status string
#        generated by the git-prompt machinery.  e.g.
#        Bash: PROMPT_COMMAND='__git_ps1 "\u@\h:\w" "\\\$ "'
#          will show username, at-sign, host, colon, cwd, then
#          various status string, followed by dollar and SP, as
#          your prompt.
#        ZSH:  precmd () { __git_ps1 "%n" ":%~$ " "|%s" }
#          will show username, pipe, then various status string,
#          followed by colon, cwd, dollar and SP, as your prompt.
#        Optionally, you can supply a third argument with a printf
#        format string to finetune the output of the branch status
#
# The repository status will be displayed only if you are currently in a
# git repository. The %s token is the placeholder for the shown status.
#
# The prompt status always includes the current branch name.
#
# In addition, if you set GIT_PS1_SHOWDIRTYSTATE to a nonempty value,
# unstaged (*) and staged (+) changes will be shown next to the branch
# name.  You can configure this per-repository with the
# bash.showDirtyState variable, which defaults to true once
# GIT_PS1_SHOWDIRTYSTATE is enabled.
#
# You can also see if currently something is stashed, by setting
# GIT_PS1_SHOWSTASHSTATE to a nonempty value. If something is stashed,
# then a '$' will be shown next to the branch name.
#
# If you would like to see if there're untracked files, then you can set
# GIT_PS1_SHOWUNTRACKEDFILES to a nonempty value. If there're untracked
# files, then a '%' will be shown next to the branch name.  You can
# configure this per-repository with the bash.showUntrackedFiles
# variable, which defaults to true once GIT_PS1_SHOWUNTRACKEDFILES is
# enabled.
#
# If you would like to see the difference between HEAD and its upstream,
# set GIT_PS1_SHOWUPSTREAM="auto".  A "<" indicates you are behind, ">"
# indicates you are ahead, "<>" indicates you have diverged and "="
# indicates that there is no difference. You can further control
# behaviour by setting GIT_PS1_SHOWUPSTREAM to a space-separated list
# of values:
#
#     verbose       show number of commits ahead/behind (+/-) upstream
#     name          if verbose, then also show the upstream abbrev name
#     legacy        don't use the '--count' option available in recent
#                   versions of git-rev-list
#     git           always compare HEAD to @{upstream}
#     svn           always compare HEAD to your SVN upstream
#
# You can change the separator between the branch name and the above
# state symbols by setting GIT_PS1_STATESEPARATOR. The default separator
# is SP.
#
# By default, __git_ps1 will compare HEAD to your SVN upstream if it can
# find one, or @{upstream} otherwise.  Once you have set
# GIT_PS1_SHOWUPSTREAM, you can override it on a per-repository basis by
# setting the bash.showUpstream config variable.
#
# If you would like to see more information about the identity of
# commits checked out as a detached HEAD, set GIT_PS1_DESCRIBE_STYLE
# to one of these values:
#
#     contains      relative to newer annotated tag (v1.6.3.2~35)
#     branch        relative to newer tag or branch (master~4)
#     describe      relative to older annotated tag (v1.6.3.1-13-gdd42c2f)
#     default       exactly matching tag
#
# If you would like a colored hint about the current dirty state, set
# GIT_PS1_SHOWCOLORHINTS to a nonempty value. The colors are based on
# the colored output of "git status -sb" and are available only when
# using __git_ps1 for PROMPT_COMMAND or precmd.
#
# If you would like __git_ps1 to do nothing in the case when the current
# directory is set up to be ignored by git, then set
# GIT_PS1_HIDE_IF_PWD_IGNORED to a nonempty value. Override this on the
# repository level by setting bash.hideIfPwdIgnored to "false".

# check whether printf supports -v
__git_printf_supports_v=
printf -v __git_printf_supports_v -- '%s' yes >/dev/null 2>&1

# stores the divergence from upstream in $p
# used by GIT_PS1_SHOWUPSTREAM
__git_ps1_show_upstream ()
{
	local key value
	local svn_remote svn_url_pattern count n
	local upstream=git legacy="" verbose="" name=""

	set -A svn_remote
	# get some config options from git-config
	set -A output $(git config -z --get-regexp '^(svn-remote\..*\.url|bash\.showupstream)$' 2>/dev/null | tr '\0\n' '\n ')
	count=0
	for idx in ${output[@]}; do
		if [ $((count % 2)) == 0 ]; then
			key=${output[$count]}
			value=${output[$((count+1))]}
		fi

		case "$key" in
		bash.showupstream)
			GIT_PS1_SHOWUPSTREAM="$value"
			if [[ -z "${GIT_PS1_SHOWUPSTREAM}" ]]; then
				p=""
				return
			fi
			;;
		svn-remote.*.url)
			svn_remote[$((${#svn_remote[@]} + 1))]="$value"
			svn_url_pattern="$svn_url_pattern\\|$value"
			upstream=svn+git # default upstream is SVN if available, else git
			;;
		esac
		((count=count+1))
	done

	# parse configuration values
	for option in ${GIT_PS1_SHOWUPSTREAM}; do
		case "$option" in
		git|svn) upstream="$option" ;;
		verbose) verbose=1 ;;
		legacy)  legacy=1  ;;
		name)    name=1 ;;
		esac
	done

	# Find our upstream
	case "$upstream" in
	git)    upstream="@{upstream}" ;;
	svn*)
		# get the upstream from the "git-svn-id: ..." in a commit message
		# (git-svn uses essentially the same procedure internally)
		set -A svn_upstream $(git log --first-parent -1 \
					--grep="^git-svn-id: \(${svn_url_pattern#??}\)" 2>/dev/null)
		if [[ 0 -ne ${#svn_upstream[@]} ]]; then
			svn_upstream=${svn_upstream[${#svn_upstream[@]} - 2]}
			svn_upstream=${svn_upstream%@*}
			local n_stop="${#svn_remote[@]}"
			#for ((n=1; n <= n_stop; n++)); do
			local count=1;
echo n_stop;
			for n in n_stop; do
				svn_upstream=${svn_upstream#${svn_remote[$count]}}
				((count=count+1))
			done

			if [[ -z "$svn_upstream" ]]; then
				# default branch name for checkouts with no layout:
				upstream=${GIT_SVN_ID:-git-svn}
			else
				upstream=${svn_upstream#/}
			fi
		elif [[ "svn+git" = "$upstream" ]]; then
			upstream="@{upstream}"
		fi
		;;
	esac

	# Find how many commits we are ahead/behind our upstream
	if [[ -z "$legacy" ]]; then
		count="$(git rev-list --count --left-right \
				"$upstream"...HEAD 2>/dev/null)"
	else
		# produce equivalent output to --count for older versions of git
		local commits
		if commits="$(git rev-list --left-right "$upstream"...HEAD 2>/dev/null)"
		then
			local commit behind=0 ahead=0
			for commit in $commits
			do
				case "$commit" in
				"<"*) ((behind++)) ;;
				*)    ((ahead++))  ;;
				esac
			done
			count="$behind	$ahead"
		else
			count=""
		fi
	fi

	# calculate the result
	if [[ -z "$verbose" ]]; then
		case "$count" in
		"") # no upstream
			p="" ;;
		"0	0") # equal to upstream
			p="=" ;;
		"0	"*) # ahead of upstream
			p=">" ;;
		*"	0") # behind upstream
			p="<" ;;
		*)	    # diverged from upstream
			p="<>" ;;
		esac
	else
		case "$count" in
		"") # no upstream
			p="" ;;
		"0	0") # equal to upstream
			p=" u=" ;;
		"0	"*) # ahead of upstream
			p=" u+${count#0	}" ;;
		*"	0") # behind upstream
			p=" u-${count%	0}" ;;
		*)	    # diverged from upstream
			p=" u+${count#*	}-${count%	*}" ;;
		esac
		if [[ -n "$count" && -n "$name" ]]; then
			__git_ps1_upstream_name=$(git rev-parse \
				--abbrev-ref "$upstream" 2>/dev/null)
			if [ $pcmode = yes ] && [ $ps1_expanded = yes ]; then
				p="$p \${__git_ps1_upstream_name}"
			else
				p=$(echo "$p ${__git_ps1_upstream_name}" | sed 's/\n//g')
				# not needed anymore; keep user's
				# environment clean
				unset __git_ps1_upstream_name
			fi
		fi
	fi

}

# Helper function that is meant to be called from __git_ps1.  It
# injects color codes into the appropriate gitstring variables used
# to build a gitstring.
__git_ps1_colorize_gitstring ()
{
	if [[ -n ${ZSH_VERSION-} ]]; then
		local c_red='%F{red}'
		local c_green='%F{green}'
		local c_lblue='%F{blue}'
		local c_clear='%f'
	else
		# Using \[ and \] around colors is necessary to prevent
		# issues with command line editing/browsing/completion!
		local c_red='\[\e[31m\]'
		local c_green='\[\e[32m\]'
		local c_lblue='\[\e[1;34m\]'
		local c_clear='\[\e[0m\]'
	fi
	local bad_color=$c_red
	local ok_color=$c_green
	local flags_color="$c_lblue"

	local branch_color=""
	if [ $detached = no ]; then
		branch_color="$ok_color"
	else
		branch_color="$bad_color"
	fi
	c="$branch_color$c"

	z="$c_clear$z"
	if [ "$w" = "*" ]; then
		w="$bad_color$w"
	fi
	if [ -n "$i" ]; then
		i="$ok_color$i"
	fi
	if [ -n "$s" ]; then
		s="$flags_color$s"
	fi
	if [ -n "$u" ]; then
		u="$bad_color$u"
	fi
	r="$c_clear$r"
}

__git_eread ()
{
	local f="$1"
	shift
	test -r "$f" && read "$@" <"$f"
}

# __git_ps1 accepts 0 or 1 arguments (i.e., format string)
# when called from PS1 using command substitution
# in this mode it prints text to add to bash PS1 prompt (includes branch name)
#
# __git_ps1 requires 2 or 3 arguments when called from PROMPT_COMMAND (pc)
# in that case it _sets_ PS1. The arguments are parts of a PS1 string.
# when two arguments are given, the first is prepended and the second appended
# to the state string when assigned to PS1.
# The optional third parameter will be used as printf format string to further
# customize the output of the git-status string.
# In this mode you can request colored hints using GIT_PS1_SHOWCOLORHINTS=true
__git_ps1 ()
{
	# preserve exit status
	local exit=$?
	local pcmode=no
	local detached=no
	local ps1pc_start='\u@\h:\w '
	local ps1pc_end='\$ '
	local printf_format=' (%s)'

	case "$#" in
		2|3)	pcmode=yes
			ps1pc_start="$1"
			ps1pc_end="$2"
			printf_format="${3:-$printf_format}"
			# set PS1 to a plain prompt so that we can
			# simply return early if the prompt should not
			# be decorated
			PS1="$ps1pc_start$ps1pc_end"
		;;
		0|1)	printf_format="${1:-$printf_format}"
		;;
		*)	return $exit
		;;
	esac

	# ps1_expanded:  This variable is set to 'yes' if the shell
	# subjects the value of PS1 to parameter expansion:
	#
	#   * bash does unless the promptvars option is disabled
	#   * zsh does not unless the PROMPT_SUBST option is set
	#   * POSIX shells always do
	#
	# If the shell would expand the contents of PS1 when drawing
	# the prompt, a raw ref name must not be included in PS1.
	# This protects the user from arbitrary code execution via
	# specially crafted ref names.  For example, a ref named
	# 'refs/heads/$(IFS=_;cmd=sudo_rm_-rf_/;$cmd)' might cause the
	# shell to execute 'sudo rm -rf /' when the prompt is drawn.
	#
	# Instead, the ref name should be placed in a separate global
	# variable (in the __git_ps1_* namespace to avoid colliding
	# with the user's environment) and that variable should be
	# referenced from PS1.  For example:
	#
	#     __git_ps1_foo=$(do_something_to_get_ref_name)
	#     PS1="...stuff...\${__git_ps1_foo}...stuff..."
	#
	# If the shell does not expand the contents of PS1, the raw
	# ref name must be included in PS1.
	#
	# The value of this variable is only relevant when in pcmode.
	#
	# Assume that the shell follows the POSIX specification and
	# expands PS1 unless determined otherwise.  (This is more
	# likely to be correct if the user has a non-bash, non-zsh
	# shell and safer than the alternative if the assumption is
	# incorrect.)
	#
	local ps1_expanded=yes
	[ -z "${ZSH_VERSION-}" ] || [[ -o PROMPT_SUBST ]] || ps1_expanded=no
	[ -z "${BASH_VERSION-}" ] || shopt -q promptvars || ps1_expanded=no

	local repo_info rev_parse_exit_code
	set -A repo_info $(git rev-parse --git-dir --is-inside-git-dir \
		--is-bare-repository --is-inside-work-tree \
		--short HEAD 2>/dev/null)
	rev_parse_exit_code="$?"

	if [ -z "$repo_info" ]; then
		return $exit
	fi

	local short_sha=""
	idx=${#repo_info[@]}
	((idx=idx-1))
	if [ "$rev_parse_exit_code" = "0" ]; then
		short_sha="${repo_info[$idx]}"
		((idx=idx-1))
	fi
	local inside_worktree="${repo_info[$idx]}"
	((idx=idx-1))
	local bare_repo="${repo_info[$idx]}"
	((idx=idx-1))
	local inside_gitdir="${repo_info[$idx]}"
	((idx=idx-1))
	local g="${repo_info[0]}"

	if [ "true" = "$inside_worktree" ] &&
	   [ -n "${GIT_PS1_HIDE_IF_PWD_IGNORED-}" ] &&
	   [ "$(git config --bool bash.hideIfPwdIgnored)" != "false" ] &&
	   git check-ignore -q .
	then
		return $exit
	fi

	local r=""
	local b=""
	local step=""
	local total=""
	if [ -d "$g/rebase-merge" ]; then
		__git_eread "$g/rebase-merge/head-name" b
		__git_eread "$g/rebase-merge/msgnum" step
		__git_eread "$g/rebase-merge/end" total
		if [ -f "$g/rebase-merge/interactive" ]; then
			r="|REBASE-i"
		else
			r="|REBASE-m"
		fi
	else
		if [ -d "$g/rebase-apply" ]; then
			__git_eread "$g/rebase-apply/next" step
			__git_eread "$g/rebase-apply/last" total
			if [ -f "$g/rebase-apply/rebasing" ]; then
				__git_eread "$g/rebase-apply/head-name" b
				r="|REBASE"
			elif [ -f "$g/rebase-apply/applying" ]; then
				r="|AM"
			else
				r="|AM/REBASE"
			fi
		elif [ -f "$g/MERGE_HEAD" ]; then
			r="|MERGING"
		elif [ -f "$g/CHERRY_PICK_HEAD" ]; then
			r="|CHERRY-PICKING"
		elif [ -f "$g/REVERT_HEAD" ]; then
			r="|REVERTING"
		elif [ -f "$g/BISECT_LOG" ]; then
			r="|BISECTING"
		fi

		if [ -n "$b" ]; then
			:
		elif [ -h "$g/HEAD" ]; then
			# symlink symbolic ref
			b="$(git symbolic-ref HEAD 2>/dev/null)"
		else
			local head=""
			if ! __git_eread "$g/HEAD" head; then
				return $exit
			fi
			# is it a symbolic ref?
			b="${head#ref: }"
			if [ "$head" = "$b" ]; then
				detached=yes
				b="$(
				case "${GIT_PS1_DESCRIBE_STYLE-}" in
				(contains)
					git describe --contains HEAD ;;
				(branch)
					git describe --contains --all HEAD ;;
				(describe)
					git describe HEAD ;;
				(* | default)
					git describe --tags --exact-match HEAD ;;
				esac 2>/dev/null)" ||

				b="$short_sha..."
				b="($b)"
			fi
		fi
	fi

	if [ -n "$step" ] && [ -n "$total" ]; then
		r="$r $step/$total"
	fi

	local w=""
	local i=""
	local s=""
	local u=""
	local c=""
	local p=""

	if [ "true" = "$inside_gitdir" ]; then
		if [ "true" = "$bare_repo" ]; then
			c="BARE:"
		else
			b="GIT_DIR!"
		fi
	elif [ "true" = "$inside_worktree" ]; then
		if [ -n "${GIT_PS1_SHOWDIRTYSTATE-}" ] &&
		   [ "$(git config --bool bash.showDirtyState)" != "false" ]
		then
			git diff --no-ext-diff --quiet || w="*"
			git diff --no-ext-diff --cached --quiet || i="+"
			if [ -z "$short_sha" ] && [ -z "$i" ]; then
				i="#"
			fi
		fi
		if [ -n "${GIT_PS1_SHOWSTASHSTATE-}" ] &&
		   git rev-parse --verify --quiet refs/stash >/dev/null
		then
			s="$"
		fi

		if [ -n "${GIT_PS1_SHOWUNTRACKEDFILES-}" ] &&
		   [ "$(git config --bool bash.showUntrackedFiles)" != "false" ] &&
		   git ls-files --others --exclude-standard --directory --no-empty-directory --error-unmatch -- ':/*' >/dev/null 2>/dev/null
		then
			u="%${ZSH_VERSION+%}"
		fi

		if [ -n "${GIT_PS1_SHOWUPSTREAM-}" ]; then
			__git_ps1_show_upstream
		fi
	fi

	local z="${GIT_PS1_STATESEPARATOR-" "}"

	# NO color option unless in PROMPT_COMMAND mode
	if [ $pcmode = yes ] && [ -n "${GIT_PS1_SHOWCOLORHINTS-}" ]; then
		__git_ps1_colorize_gitstring
	fi

	b=${b##refs/heads/}
	if [ $pcmode = yes ] && [ $ps1_expanded = yes ]; then
		__git_ps1_branch_name=$b
		b="\${__git_ps1_branch_name}"
	fi

	local f="$w$i$s$u"
	local gitstring="$c$b${f:+$z$f}$r$p"

	if [ $pcmode = yes ]; then
		if [ "${__git_printf_supports_v-}" != yes ]; then
			gitstring=$(printf -- "$printf_format" "$gitstring")
		else
			printf -v gitstring -- "$printf_format" "$gitstring"
		fi
		PS1="$ps1pc_start$gitstring$ps1pc_end"
	else
		printf -- "$printf_format" "$gitstring"
	fi

	return $exit
}

Thanks. BTW I stroke out using function - it was suggested by a peer (a ksh guru), and it might work for the entry function to isolate it from the shell but other functions must use the () syntax to access variables in outer scope. More testing might be needed; I don't use it personally but I have many peers using it and i'm looking at making it available to them as well.

I'll look more deeply at your changes, however I'm aiming at ksh93 compatibility - if I can make bsd ksh happy that's even better. OTOH I wish to retain bash (my preference) and zsh (also user by peers) compatibility. I'm not very concerned about strict POSIX compliance as it would likely require dropping some speedups (or maybe spiting in multiple includes, but then multiple versions have to be maintained...)

P.S.: Pm me if you'l like followups of this, ex when I submit it to the git project. My email is in my GH commits...