From c577bc89cd591eb50288f16c624a3ef60fd4c654 Mon Sep 17 00:00:00 2001
From: Philip Withnall <withnall@endlessm.com>
Date: Tue, 12 Nov 2019 21:15:13 +0000
Subject: [PATCH] gsignal: Warn if g_signal_lookup() is called on an invalid
 signal name

And add a test for it.

Signed-off-by: Philip Withnall <withnall@endlessm.com>
---
 gobject/gsignal.c       |  3 +++
 gobject/tests/signals.c | 25 +++++++++++++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/gobject/gsignal.c b/gobject/gsignal.c
index 579eb4846..e610056d6 100644
--- a/gobject/gsignal.c
+++ b/gobject/gsignal.c
@@ -1331,6 +1331,9 @@ g_signal_lookup (const gchar *name,
       else if (!g_type_class_peek (itype))
 	g_warning (G_STRLOC ": unable to look up signal \"%s\" of unloaded type '%s'",
 		   name, g_type_name (itype));
+      else if (!is_valid_signal_name (name))
+        g_warning (G_STRLOC ": unable to look up invalid signal name \"%s\" on type '%s'",
+                   name, g_type_name (itype));
     }
   
   return signal_id;
diff --git a/gobject/tests/signals.c b/gobject/tests/signals.c
index 0864f2a31..ae8bd9dc2 100644
--- a/gobject/tests/signals.c
+++ b/gobject/tests/signals.c
@@ -1311,6 +1311,30 @@ test_lookup (void)
   g_type_class_unref (test_class);
 }
 
+static void
+test_lookup_invalid (void)
+{
+  g_test_summary ("Test that g_signal_lookup() emits a warning if looking up an invalid signal name.");
+
+  if (g_test_subprocess ())
+    {
+      GTypeClass *test_class;
+      guint signal_id;
+
+      test_class = g_type_class_ref (test_get_type ());
+
+      signal_id = g_signal_lookup ("", test_get_type ());
+      g_assert_cmpint (signal_id, ==, 0);
+
+      g_type_class_unref (test_class);
+      return;
+    }
+
+  g_test_trap_subprocess (NULL, 0, 0);
+  g_test_trap_assert_failed ();
+  g_test_trap_assert_stderr ("*WARNING*unable to look up invalid signal name*");
+}
+
 static void
 test_parse_name (void)
 {
@@ -1455,6 +1479,7 @@ main (int argc,
   g_test_add_func ("/gobject/signals/test-disconnection-wrong-object", test_signal_disconnect_wrong_object);
   g_test_add_func ("/gobject/signals/clear-signal-handler", test_clear_signal_handler);
   g_test_add_func ("/gobject/signals/lookup", test_lookup);
+  g_test_add_func ("/gobject/signals/lookup/invalid", test_lookup_invalid);
   g_test_add_func ("/gobject/signals/parse-name", test_parse_name);
   g_test_add_func ("/gobject/signals/parse-name/invalid", test_parse_name_invalid);
   g_test_add_data_func ("/gobject/signals/invalid-name/colon", "my_int:hello", test_signals_invalid_name);