From 9d43b2cfc2da2bda910010696616758aaaddb946 Mon Sep 17 00:00:00 2001
From: Idriss Fekir <mcsm224@gmail.com>
Date: Sat, 3 May 2025 01:29:47 +0200
Subject: [PATCH] GimpText: Fix crash when serializing text with missing font.

For some reason pango returns a FontDescription with name "Normal" when called
with empty string. This caused crashes in pango markup serialization. This
patch checks if the font before serialization is a valid font object, otherwise fallback to the fallback font.

Also font's reference count wasn't increased in one case when opening xcf file with a text layer.
---
 app/text/gimpfont.c |  7 ++++++-
 app/text/gimptext.c | 11 +++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/app/text/gimpfont.c b/app/text/gimpfont.c
index b8559bfe47..2e509c0554 100644
--- a/app/text/gimpfont.c
+++ b/app/text/gimpfont.c
@@ -333,7 +333,12 @@ gimp_font_deserialize_create (GType     type,
     }
 
   if (g_scanner_peek_next_token (scanner) == G_TOKEN_RIGHT_PAREN)
-    return GIMP_CONFIG (GIMP_FONT (gimp_font_get_standard ()));
+    {
+      font = GIMP_FONT (gimp_font_get_standard ());
+      g_object_ref (font);
+
+      return GIMP_CONFIG (font);
+    }
 
   scope_id = g_type_qname (type);
   old_scope_id = g_scanner_set_scope (scanner, scope_id);
diff --git a/app/text/gimptext.c b/app/text/gimptext.c
index 2ee46633da..f8eb750a06 100644
--- a/app/text/gimptext.c
+++ b/app/text/gimptext.c
@@ -587,6 +587,9 @@ gimp_text_set_property (GObject      *object,
 
         if (font != text->font && font != NULL)
           g_set_object (&text->font, font);
+        /* this is defensive to avoid some crashes */
+        else if (font == NULL) 
+          g_set_object (&text->font, GIMP_FONT (gimp_font_get_standard ()));
       }
       break;
     case PROP_FONT_SIZE:
@@ -844,6 +847,12 @@ gimp_text_serialize_property (GimpConfig       *config,
                     font = GIMP_FONT (gimp_container_search (container,
                                                              (GimpContainerSearchFunc) gimp_font_match_by_lookup_name,
                                                              (gpointer) altered_font_name));
+                  /* in case pango returns a non existant font name */
+                  if (font == NULL) 
+                    {
+                      font = GIMP_FONT (gimp_font_get_standard ());
+                      font_name = "gimpfont";
+                    }
 
                   gimp_config_writer_open   (writer, "markupfont");
                   /*lookupname format is "gimpfont%d" we keep only the "font%d",
@@ -955,6 +964,7 @@ gimp_text_deserialize_property (GimpConfig *object,
                                                                                           scanner,
                                                                                           -1,
                                                                                           NULL));
+              g_assert (GIMP_IS_FONT (font));
               replaced_markup = g_markup_printf_escaped (" font=\"%s\"", markup_fontname);
               new_markup      = g_strdup_printf (" gimpfont=\"%s\"", gimp_font_get_lookup_name (font));
               g_string_replace (markup_str, replaced_markup, new_markup, 0);
@@ -993,6 +1003,7 @@ gimp_text_deserialize_property (GimpConfig *object,
                                                                                           scanner,
                                                                                           -1,
                                                                                           NULL));
+              g_assert (GIMP_IS_FONT (font));
               g_scanner_get_next_token  (scanner); /* ) */
               g_scanner_get_next_token  (scanner); /* ) */