[vala/0.48] gtkmodule: Improve error message for invalid signal element in ui-file

[Rico Tzschichholz <ricotz src gnome org>]

commit 335b7719dee31cbf41de7deec87af4df2d1d5c8a
Author: Yotam Nachum <me yotam net>
Date:   Sat Nov 6 14:33:07 2021 +0200

    gtkmodule: Improve error message for invalid signal element in ui-file

 codegen/valagtkmodule.vala | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)
---
diff --git a/codegen/valagtkmodule.vala b/codegen/valagtkmodule.vala
index 2f3431653..a8b0d31c0 100644
--- a/codegen/valagtkmodule.vala
+++ b/codegen/valagtkmodule.vala
@@ -184,7 +184,13 @@ public class Vala.GtkModule : GSignalModule {
 
                                if (current_class != null) {
                                        if (signal_name == null || handler_name == null) {
-                                               Report.error (node.source_reference, "Invalid signal in ui 
file `%s'".printf (ui_file));
+                                               if (signal_name != null) {
+                                                       Report.error (node.source_reference, "Invalid signal 
`%s' without handler in ui file `%s'".printf (signal_name, ui_file));
+                                               } else if (handler_name != null) {
+                                                       Report.error (node.source_reference, "Invalid signal 
without name in ui file `%s'".printf (ui_file));
+                                               } else {
+                                                       Report.error (node.source_reference, "Invalid signal 
without name and handler in ui file `%s'".printf (ui_file));
+                                               }
                                                current_token = reader.read_token (null, null);
                                                continue;
                                        }