[gimp] app: don't g_return_if_fail() in gimp_device_info_set_device()

[Michael Natterer <mitch src gnome org>]

commit f06d0485e697b6a018e4ee774f37a5e7f33aa592
Author: Michael Natterer <mitch gimp org>
Date:   Sun Jun 17 15:09:56 2018 +0200

    app: don't g_return_if_fail() in gimp_device_info_set_device()
    
    when the GimpDeviceInfo already has a device. This is not a programming
    error that should trigger a bug report popup, it's something else about
    non-uniqueness of device names, or whatever. Simply g_printerr() a more
    useful message that can help to debug this and bail out.

 app/widgets/gimpdeviceinfo.c | 35 ++++++++++++++++++++++++++---------
 app/widgets/gimpdeviceinfo.h |  2 +-
 2 files changed, 27 insertions(+), 10 deletions(-)
---
diff --git a/app/widgets/gimpdeviceinfo.c b/app/widgets/gimpdeviceinfo.c
index 3847640fff..99dec841cf 100644
--- a/app/widgets/gimpdeviceinfo.c
+++ b/app/widgets/gimpdeviceinfo.c
@@ -600,21 +600,36 @@ gimp_device_info_get_device (GimpDeviceInfo  *info,
   return info->device;
 }
 
-void
+gboolean
 gimp_device_info_set_device (GimpDeviceInfo *info,
                              GdkDevice      *device,
                              GdkDisplay     *display)
 {
   gint i;
 
-  g_return_if_fail (GIMP_IS_DEVICE_INFO (info));
-  g_return_if_fail ((device == NULL && display == NULL) ||
-                    (GDK_IS_DEVICE (device) && GDK_IS_DISPLAY (display)));
-  g_return_if_fail ((info->device == NULL && GDK_IS_DEVICE (device)) ||
-                    (GDK_IS_DEVICE (info->device) && device == NULL));
-  g_return_if_fail (device == NULL ||
-                    strcmp (gdk_device_get_name (device),
-                            gimp_object_get_name (info)) == 0);
+  g_return_val_if_fail (GIMP_IS_DEVICE_INFO (info), FALSE);
+  g_return_val_if_fail ((device == NULL && display == NULL) ||
+                        (GDK_IS_DEVICE (device) && GDK_IS_DISPLAY (display)),
+                        FALSE);
+
+  if (device && info->device)
+    {
+      g_printerr ("%s: trying to set GdkDevice '%s' on GimpDeviceInfo "
+                  "which already has a device\n",
+                  G_STRFUNC, gdk_device_get_name (device));
+      return FALSE;
+    }
+  else if (! device && ! info->device)
+    {
+      g_printerr ("%s: trying to unset GdkDevice of GimpDeviceInfo '%s'"
+                  "which has no device\n",
+                  G_STRFUNC, gimp_object_get_name (info));
+      return FALSE;
+    }
+
+  g_return_val_if_fail (device == NULL ||
+                        strcmp (gdk_device_get_name (device),
+                                gimp_object_get_name (info)) == 0, FALSE);
 
   g_object_freeze_notify (G_OBJECT (info));
 
@@ -695,6 +710,8 @@ gimp_device_info_set_device (GimpDeviceInfo *info,
   g_object_notify (G_OBJECT (info), "tool-hardware-id");
 
   g_object_thaw_notify (G_OBJECT (info));
+
+  return TRUE;
 }
 
 void
diff --git a/app/widgets/gimpdeviceinfo.h b/app/widgets/gimpdeviceinfo.h
index 9ba6f7fee8..bc3e657118 100644
--- a/app/widgets/gimpdeviceinfo.h
+++ b/app/widgets/gimpdeviceinfo.h
@@ -78,7 +78,7 @@ GimpDeviceInfo  * gimp_device_info_new                  (Gimp            *gimp,
 
 GdkDevice       * gimp_device_info_get_device           (GimpDeviceInfo  *info,
                                                          GdkDisplay     **display);
-void              gimp_device_info_set_device           (GimpDeviceInfo  *info,
+gboolean          gimp_device_info_set_device           (GimpDeviceInfo  *info,
                                                          GdkDevice       *device,
                                                          GdkDisplay      *display);