[glib] g_error_new_valist, g_error_copy: warn if domain is 0 or message is NULL

[Matthias Clasen <matthiasc src gnome org>]

commit 6d9f874330ee27ea09b383cb30718a492f6539dd
Author: Simon McVittie <simon mcvittie collabora co uk>
Date:   Fri Sep 30 14:02:29 2011 +0100

    g_error_new_valist, g_error_copy: warn if domain is 0 or message is NULL
    
    Neither of those usages is valid, but there's a lot of use of 0 as a
    domain "in the wild", so we can't g_return_if_fail yet.
    
    Signed-off-by: Simon McVittie <simon mcvittie collabora co uk>
    Bug: https://bugzilla.gnome.org/show_bug.cgi?id=660371

 glib/gerror.c |   11 +++++++++++
 1 files changed, 11 insertions(+), 0 deletions(-)
---
diff --git a/glib/gerror.c b/glib/gerror.c
index 7e2d636..6cc3cfb 100644
--- a/glib/gerror.c
+++ b/glib/gerror.c
@@ -382,6 +382,14 @@ g_error_new_valist (GQuark       domain,
 {
   GError *error;
 
+  /* Historically, GError allowed this (although it was never meant to work),
+   * and it has significant use in the wild, which g_return_val_if_fail
+   * would break. It should maybe g_return_val_if_fail in GLib 4.
+   * (GNOME#660371, GNOME#560482)
+   */
+  g_warn_if_fail (domain != 0);
+  g_warn_if_fail (format != NULL);
+
   error = g_slice_new (GError);
 
   error->domain = domain;
@@ -484,6 +492,9 @@ g_error_copy (const GError *error)
   GError *copy;
  
   g_return_val_if_fail (error != NULL, NULL);
+  /* See g_error_new_valist for why these don't return */
+  g_warn_if_fail (error->domain != 0);
+  g_warn_if_fail (error->message != NULL);
 
   copy = g_slice_new (GError);