Use `stty size` or zero as a fallback for $COLUMNS

Fixes #924

powerline/bindings/bash/powerline.sh

@@ -1,3 +1,15 @@
+_powerline_columns_fallback() {
+	if which stty &>/dev/null ; then
+		local cols="$(stty size 2>/dev/null)"
+		if ! test -z "$cols" ; then
+			echo "${cols#* }"
+			return 0
+		fi
+	fi
+	echo 0
+	return 0
+}
+
 _powerline_init_tmux_support() {
 	if test -n "$TMUX" && tmux refresh -S &>/dev/null ; then
 		# TMUX variable may be unset to create new tmux session inside this one
@@ -16,7 +28,7 @@ _powerline_init_tmux_support() {
 		}
 
 		_powerline_tmux_set_columns() {
-			_powerline_tmux_setenv COLUMNS "$COLUMNS"
+			_powerline_tmux_setenv COLUMNS "${COLUMNS:-$(_powerline_columns_fallback)}"
 		}
 
 		trap "_powerline_tmux_set_columns" SIGWINCH
@@ -32,7 +44,7 @@ _powerline_init_tmux_support() {
 
 _run_powerline() {
 	# Arguments: side, last_exit_code, jobnum
-	$POWERLINE_COMMAND shell $1 -w $COLUMNS -r bash_prompt --last_exit_code=$2 --jobnum=$3
+	$POWERLINE_COMMAND shell $1 -w "${COLUMNS:-$(_powerline_columns_fallback)}" -r bash_prompt --last_exit_code=$2 --jobnum=$3
 }
 
 _powerline_prompt() {

powerline/bindings/fish/powerline-setup.fish

@@ -1,4 +1,23 @@
 function powerline-setup
+	function _powerline_columns_fallback
+		if which stty ^/dev/null
+			if stty size ^/dev/null
+				stty size | cut -d' ' -f2
+				return 0
+			end
+		end
+		echo 0
+		return 0
+	end
+
+	function _powerline_columns
+		if test -z "$COLUMNS"
+			_powerline_columns_fallback
+		else
+			echo "$COLUMNS"
+		end
+	end
+
 	if test -z "$POWERLINE_NO_FISH_PROMPT$POWERLINE_NO_SHELL_PROMPT"
 		if test -z "$POWERLINE_COMMAND"
 			if which powerline-client >/dev/null
@@ -20,11 +39,11 @@ function powerline-setup
 			if test -z "$POWERLINE_NO_FISH_ABOVE$POWERLINE_NO_SHELL_ABOVE"
 				set promptside aboveleft
 				set rpromptpast 'echo -n " "'
-				set columnsexpr '(math $COLUMNS - 1)'
+				set columnsexpr '(math (_powerline_columns) - 1)'
 			else
 				set promptside left
 				set rpromptpast
-				set columnsexpr '$COLUMNS'
+				set columnsexpr '(_powerline_columns)'
 			end
 			eval "
 			function fish_prompt
@@ -53,7 +72,7 @@ function powerline-setup
 					_powerline_tmux_setenv PWD "$PWD"
 				end
 				function --on-signal WINCH _powerline_tmux_set_columns
-					_powerline_tmux_setenv COLUMNS "$COLUMNS"
+					_powerline_tmux_setenv COLUMNS (_powerline_columns)
 				end
 				_powerline_tmux_set_columns
 				_powerline_tmux_set_pwd

powerline/bindings/zsh/powerline.zsh

@@ -8,6 +8,18 @@ if test -z "${POWERLINE_COMMAND}" ; then
 	fi
 fi
 
+_powerline_columns_fallback() {
+	if which stty &>/dev/null ; then
+		local cols="$(stty size 2>/dev/null)"
+		if ! test -z "$cols" ; then
+			echo "${cols#* }"
+			return 0
+		fi
+	fi
+	echo 0
+	return 0
+}
+
 integer _POWERLINE_JOBNUM
 
 _powerline_init_tmux_support() {
@@ -28,7 +40,7 @@ _powerline_init_tmux_support() {
 		}
 
 		function -g _powerline_tmux_set_columns() {
-			_powerline_tmux_setenv COLUMNS "$COLUMNS"
+			_powerline_tmux_setenv COLUMNS "${COLUMNS:-$(_powerline_columns_fallback)}"
 		}
 
 		chpwd_functions+=( _powerline_tmux_set_pwd )
@@ -126,7 +138,7 @@ _powerline_setup_prompt() {
 		new_args_2+=' -R local_theme=continuation'
 		local add_args_3=$add_args' -R local_theme=select'
 		local add_args_2=$add_args$new_args_2
-		add_args+=' --width=$(( COLUMNS - 1 ))'
+		add_args+=' --width=$(( ${COLUMNS:-$(_powerline_columns_fallback)} - 1 ))'
 		local add_args_r2=$add_args$new_args_2
 		PS1='$($POWERLINE_COMMAND shell aboveleft -r zsh_prompt '$add_args')'
 		RPS1='$($POWERLINE_COMMAND shell right -r zsh_prompt '$add_args')'