From 830c4578cdc4478e3e74286bb1d007e184700ae1 Mon Sep 17 00:00:00 2001
From: Mark Levedahl <mlevedahl@gmail.com>
Date: Sun, 28 Sep 2025 23:04:54 -0400
Subject: [PATCH] gitk: add proc run_themeloader

gitk currently accepts a single themeloader file via the config file,
and will source this with errors reported to the console. This is fine
for simple configuration, but will not support interactive theme
exploration from the gui. In particular, a themeloader file must be
sourced only once as the themes defined cannot be re-defined. Also,
errors must be handled rather than just aborting while printing to the
console.  So, add a proc to handle the above, supporting expansion of
the gui config pages.

Signed-off-by: Mark Levedahl <mlevedahl@gmail.com>
---
 gitk | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/gitk b/gitk
index 2d6a1693f6..4798ff3709 100755
--- a/gitk
+++ b/gitk
@@ -11861,6 +11861,23 @@ proc choose_extdiff {} {
     }
 }
 
+proc run_themeloader {f} {
+    if {![info exists ::_themefiles_seen]} {
+        set ::_themefiles_seen [dict create]
+    }
+
+    set fn [file normalize $f]
+    if {![dict exists $::_themefiles_seen $fn]} {
+        if {[catch {source $fn} err]} {
+            error_popup "could not interpret: $fn\n$err"
+            dict set ::_themefiles_seen $fn 0
+        } else {
+            dict set ::_themefiles_seen $fn 1
+        }
+    }
+    return [dict get $::_themefiles_seen $fn]
+}
+
 proc choosecolor {v vi prefspage x} {
     global $v
 
@@ -12742,7 +12759,10 @@ set nullid2 "0000000000000000000000000000000000000001"
 set nullfile "/dev/null"
 
 if {[file exists $themeloader]} {
-    source $themeloader
+    if {[run_themeloader $themeloader] == 0} {
+        puts stderr "Could not interpret themeloader: $themeloader"
+        exit 1
+    }
 }
 
 set appname "gitk"