bash_completion: don't complete export with "garbage" when mq is not around

The "garbage" is the output of hg help printed when a command is not found.

contrib/bash_completion

@@ -1,390 +1,395 b''
 # bash completion for the Mercurial distributed SCM
 
 # Docs:
 #
 # If you source this file from your .bashrc, bash should be able to
 # complete a command line that uses hg with all the available commands
 # and options and sometimes even arguments.
 #
 # Mercurial allows you to define additional commands through extensions.
 # Bash should be able to automatically figure out the name of these new
 # commands and their options.  If you also want to tell it how to
 # complete non-option arguments, see below for how to define an
 # _hg_cmd_foo function.
 #
 #
 # Notes about completion for specific commands:
 #
 # - the completion function for the email command from the patchbomb
 #   extension will try to call _hg_emails to get a list of e-mail
 #   addresses.  It's up to the user to define this function.  For
 #   example, put the addresses of the lists that you usually patchbomb
 #   in ~/.patchbomb-to and the addresses that you usually use to send
 #   the patchbombs in ~/.patchbomb-from and use something like this:
 #
 #      _hg_emails()
 #      {
 #          if [ -r ~/.patchbomb-$1 ]; then
 #              cat ~/.patchbomb-$1
 #          fi
 #      }
 # 
 #
 # Writing completion functions for additional commands:
 #
 # If it exists, the function _hg_cmd_foo will be called without
 # arguments to generate the completion candidates for the hg command
 # "foo".
 #
 # In addition to the regular completion variables provided by bash,
 # the following variables are also set:
 # - $hg - the hg program being used (e.g. /usr/bin/hg)
 # - $cmd - the name of the hg command being completed
 # - $cmd_index - the index of $cmd in $COMP_WORDS
 # - $cur - the current argument being completed
 # - $prev - the argument before $cur
 # - $global_args - "|"-separated list of global options that accept
 #                  an argument (e.g. '--cwd|-R|--repository')
 # - $canonical - 1 if we canonicalized $cmd before calling the function
 #                0 otherwise
 # 
 
 shopt -s extglob
 
 _hg_commands()
 {
     local commands
     commands="$("$hg" debugcomplete "$cur" 2>/dev/null)" || commands=""
     COMPREPLY=(${COMPREPLY[@]:-} $(compgen -W '$commands' -- "$cur"))
 }
 
 _hg_paths()
 {
     local paths="$("$hg" paths 2>/dev/null | sed -e 's/ = .*$//')"
     COMPREPLY=(${COMPREPLY[@]:-} $(compgen -W '$paths' -- "$cur"))
 }
 
 _hg_repos()
 {
     local i
     for i in $(compgen -d -- "$cur"); do
 	test ! -d "$i"/.hg || COMPREPLY=(${COMPREPLY[@]:-} "$i")
     done
 }
 
 _hg_status()
 {
     local files="$("$hg" status -n$1 . 2>/dev/null)"
     COMPREPLY=(${COMPREPLY[@]:-} $(compgen -W '$files' -- "$cur"))
 }
 
 _hg_tags()
 {
     local tags="$("$hg" tags -q 2>/dev/null)"
     local IFS=$'\n'
     COMPREPLY=(${COMPREPLY[@]:-} $(compgen -W '$tags' -- "$cur"))
 }
 
 # this is "kind of" ugly...
 _hg_count_non_option()
 {
     local i count=0
     local filters="$1"
 
     for ((i=1; $i<=$COMP_CWORD; i++)); do
 	if [[ "${COMP_WORDS[i]}" != -* ]]; then
 	    if [[ ${COMP_WORDS[i-1]} == @($filters|$global_args) ]]; then
 		continue
 	    fi
 	    count=$(($count + 1))
 	fi
     done
 
     echo $(($count - 1))
 }
 
 _hg()
 {
     local cur prev cmd cmd_index opts i
     # global options that receive an argument
     local global_args='--cwd|-R|--repository'
     local hg="$1"
 
     COMPREPLY=()
     cur="$2"
     prev="$3"
 
     # searching for the command
     # (first non-option argument that doesn't follow a global option that
     #  receives an argument)
     for ((i=1; $i<=$COMP_CWORD; i++)); do
 	if [[ ${COMP_WORDS[i]} != -* ]]; then
 	    if [[ ${COMP_WORDS[i-1]} != @($global_args) ]]; then
 		cmd="${COMP_WORDS[i]}"
 		cmd_index=$i
 		break
 	    fi
 	fi
     done
 
     if [[ "$cur" == -* ]]; then
 	opts=$("$hg" debugcomplete --options "$cmd" 2>/dev/null)
 
 	COMPREPLY=(${COMPREPLY[@]:-} $(compgen -W '$opts' -- "$cur"))
 	return
     fi
 
     # global options
     case "$prev" in
 	-R|--repository)
 	    _hg_repos
 	    return
 	;;
 	--cwd)
 	    # Stick with default bash completion
 	    return
 	;;
     esac
 
     if [ -z "$cmd" ] || [ $COMP_CWORD -eq $i ]; then
 	_hg_commands
 	return
     fi
 
     # try to generate completion candidates for whatever command the user typed
     local help
     local canonical=0
     if _hg_command_specific; then
 	return
     fi
 
     # canonicalize the command name and try again
     help=$("$hg" help "$cmd" 2>/dev/null)
     if [ $? -ne 0 ]; then
 	# Probably either the command doesn't exist or it's ambiguous
 	return
     fi
     cmd=${help#hg }
     cmd=${cmd%%[$' \n']*}
     canonical=1
     _hg_command_specific
 }
 
 _hg_command_specific()
 {
     if [ "$(type -t "_hg_cmd_$cmd")" = function ]; then
 	"_hg_cmd_$cmd"
 	return 0
     fi
 
     if [ "$cmd" != status ] && [ "$prev" = -r ] || [ "$prev" == --rev ]; then
 	if [ $canonical = 1 ]; then
 	    _hg_tags
 	    return 0
 	elif [[ status != "$cmd"* ]]; then
 	    _hg_tags
 	    return 0
 	else
 	    return 1
 	fi
     fi
 
     case "$cmd" in
 	help)
 	    _hg_commands
 	;;
 	export|manifest|update)
 	    _hg_tags
 	;;
 	pull|push|outgoing|incoming)
 	    _hg_paths
 	    _hg_repos
 	;;
 	paths)
 	    _hg_paths
 	;;
 	add)
 	    _hg_status "u"
 	;;
 	commit)
 	    _hg_status "mar"
 	;;
 	remove)
 	    _hg_status "d"
 	;;
 	forget)
 	    _hg_status "a"
 	;;
 	diff)
 	    _hg_status "mar"
 	;;
 	revert)
 	    _hg_status "mard"
 	;;
 	clone)
 	    local count=$(_hg_count_non_option)
 	    if [ $count = 1 ]; then
 		_hg_paths
 	    fi
 	    _hg_repos
 	;;
 	debugindex|debugindexdot)
 	    COMPREPLY=(${COMPREPLY[@]:-} $(compgen -f -X "!*.i" -- "$cur"))
 	;;
 	debugdata)
 	    COMPREPLY=(${COMPREPLY[@]:-} $(compgen -f -X "!*.d" -- "$cur"))
 	;;
 	*)
 	    return 1
 	;;
     esac
 
     return 0
 }
 
 complete -o bashdefault -o default -F _hg hg 2>/dev/null \
     || complete -o default -F _hg hg
 
 
 # Completion for commands provided by extensions
 
 # mq
 _hg_ext_mq_patchlist()
 {
-    local patches=$("$hg" $1 2>/dev/null)
-    COMPREPLY=(${COMPREPLY[@]:-} $(compgen -W '$patches' -- "$cur"))
+    local patches
+    patches=$("$hg" $1 2>/dev/null)
+    if [ $? -eq 0 ] && [ "$patches" ]; then
+	COMPREPLY=(${COMPREPLY[@]:-} $(compgen -W '$patches' -- "$cur"))
+	return 0
+    fi
+    return 1
 }
 
 _hg_ext_mq_queues()
 {
     local root=$("$hg" root 2>/dev/null)
     local n
     for n in $(cd "$root"/.hg && compgen -d -- "$cur"); do
 	# I think we're usually not interested in the regular "patches" queue
 	# so just filter it.
 	if [ "$n" != patches ] && [ -e "$root/.hg/$n/series" ]; then
 	    COMPREPLY=(${COMPREPLY[@]:-} "$n")
 	fi
     done
 }
 
 _hg_cmd_qpop()
 {
     if [[ "$prev" = @(-n|--name) ]]; then
 	_hg_ext_mq_queues
 	return
     fi
     _hg_ext_mq_patchlist qapplied
 }
 
 _hg_cmd_qpush()
 {
     if [[ "$prev" = @(-n|--name) ]]; then
 	_hg_ext_mq_queues
 	return
     fi
     _hg_ext_mq_patchlist qunapplied
 }
 
 _hg_cmd_qdelete()
 {
     _hg_ext_mq_patchlist qunapplied
 }
 
 _hg_cmd_qsave()
 {
     if [[ "$prev" = @(-n|--name) ]]; then
 	_hg_ext_mq_queues
 	return
     fi
 }
 
 _hg_cmd_strip()
 {
     _hg_tags
 }
 
 _hg_cmd_qcommit()
 {
     local root=$("$hg" root 2>/dev/null)
     # this is run in a sub-shell, so we can't use _hg_status
     local files=$(cd "$root/.hg/patches" 2>/dev/null &&
                   "$hg" status -nmar 2>/dev/null)
     COMPREPLY=(${COMPREPLY[@]:-} $(compgen -W '$files' -- "$cur"))
 }
 
 _hg_cmd_export()
 {
     _hg_ext_mq_patchlist qapplied
 }
 
 
 # hbisect
 _hg_cmd_bisect()
 {
     local i subcmd
 
     # find the sub-command
     for ((i=cmd_index+1; i<=COMP_CWORD; i++)); do
 	if [[ ${COMP_WORDS[i]} != -* ]]; then
 	    if [[ ${COMP_WORDS[i-1]} != @($global_args) ]]; then
 		subcmd="${COMP_WORDS[i]}"
 		break
 	    fi
 	fi
     done
 
     if [ -z "$subcmd" ] || [ $COMP_CWORD -eq $i ] || [ "$subcmd" = help ]; then
 	COMPREPLY=(${COMPREPLY[@]:-} 
 		   $(compgen -W 'bad good help init next reset' -- "$cur"))
 	return
     fi
 
     case "$subcmd" in
 	good|bad)
 	    _hg_tags
 	    ;;
     esac
 
     return
 }
 
 
 # patchbomb
 _hg_cmd_email()
 {
     case "$prev" in
 	-c|--cc|-t|--to|-f|--from)
 	    # we need an e-mail address. let the user provide a function 
 	    # to get them
 	    if [ "$(type -t _hg_emails)" = function ]; then
 		local arg=to
 		if [[ "$prev" == @(-f|--from) ]]; then
 		    arg=from
 		fi
 		local addresses=$(_hg_emails $arg)
 		COMPREPLY=(${COMPREPLY[@]:-}
 			   $(compgen -W '$addresses' -- "$cur"))
 	    fi
 	    return
 	    ;;
 	-m|--mbox)
 	    # fallback to standard filename completion
 	    return
 	    ;;
 	-s|--subject)
 	    # free form string
 	    return
 	    ;;
     esac
 
     _hg_tags
     return
 }
 
 
 # gpg
 _hg_cmd_sign()
 {
     _hg_tags
 }