From eb859df85e480ae4aa76a0d8358054b10d91749c Mon Sep 17 00:00:00 2001
From: Paul Mackerras <paulus@samba.org>
Date: Sun, 3 May 2015 15:11:29 +1000
Subject: [PATCH] gitk: Fix error when changing colors after closing "List
 references" window

This fixes an error that manifests itself if the user opens the
"List references" window and the closes it, and subsequently opens
the Preferences window and changes one of the colors.  When the
user clicks OK, and error popup appears with the message:

Error: invalid command name ".showrefs.list"

This is because .showrefs.list was added to the list of windows to
be notified on foreground/background color changes, but the window
no longer exists.  We fix the bug by checking whether the window
exists before trying to change its colors.  As an optimization, we
also avoid adding the .showrefs.list window to the list a second
time.

Signed-off-by: Paul Mackerras <paulus@samba.org>
---
 gitk | 18 +++++++++++++-----
 1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/gitk b/gitk
index 07bdff6e5f..c18670488d 100755
--- a/gitk
+++ b/gitk
@@ -9819,8 +9819,10 @@ proc showrefs {} {
 	-width 30 -height 20 -cursor $maincursor \
 	-spacing1 1 -spacing3 1 -state disabled
     $top.list tag configure highlight -background $selectbgcolor
-    lappend bglist $top.list
-    lappend fglist $top.list
+    if {![lsearch -exact $bglist $top.list]} {
+	lappend bglist $top.list
+	lappend fglist $top.list
+    }
     ${NS}::scrollbar $top.ysb -command "$top.list yview" -orient vertical
     ${NS}::scrollbar $top.xsb -command "$top.list xview" -orient horizontal
     grid $top.list $top.ysb -sticky nsew
@@ -11532,7 +11534,9 @@ proc choosecolor {v vi w x cmd} {
 proc setselbg {c} {
     global bglist cflist
     foreach w $bglist {
-	$w configure -selectbackground $c
+	if {[winfo exists $w]} {
+	    $w configure -selectbackground $c
+	}
     }
     $cflist tag configure highlight \
 	-background [$cflist cget -selectbackground]
@@ -11558,7 +11562,9 @@ proc setbg {c} {
     global bglist
 
     foreach w $bglist {
-	$w conf -background $c
+	if {[winfo exists $w]} {
+	    $w conf -background $c
+	}
     }
 }
 
@@ -11566,7 +11572,9 @@ proc setfg {c} {
     global fglist canv
 
     foreach w $fglist {
-	$w conf -foreground $c
+	if {[winfo exists $w]} {
+	    $w conf -foreground $c
+	}
     }
     allcanvs itemconf text -fill $c
     $canv itemconf circle -outline $c
-- 
2.39.5