[gnome-shell/gnome-3-32] keyring-prompt: relax NULL check in remove_mnemonics()

[Bastien Nocera <hadess src gnome org>]

commit b118c874da74fd0ae9aba8261b86a02f0cdede9b
Author: Cosimo Cecchi <cosimo endlessm com>
Date:   Sun May 26 10:16:03 2019 -0700

    keyring-prompt: relax NULL check in remove_mnemonics()
    
    Instead of considering a GValue containing a NULL string to be a
    programmer error, simply return NULL.
    remove_mnemonics() is in fact called on the value of the
    "choice-label" property as well, which has NULL as its default
    value.
    
    This prevents triggering the following gnome-shell warning:
    
    gnome-shell[1082]: remove_mnemonics: assertion 'label != NULL' failed
    
    https://gitlab.gnome.org/GNOME/gnome-shell/merge_requests/555

 src/shell-keyring-prompt.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)
---
diff --git a/src/shell-keyring-prompt.c b/src/shell-keyring-prompt.c
index 7ab061c67..0a72340c3 100644
--- a/src/shell-keyring-prompt.c
+++ b/src/shell-keyring-prompt.c
@@ -115,7 +115,8 @@ remove_mnemonics (const GValue *value)
   g_return_val_if_fail (G_VALUE_HOLDS_STRING (value), NULL);
 
   label = g_value_get_string (value);
-  g_return_val_if_fail (label != NULL, NULL);
+  if (!label)
+    return NULL;
 
   /* Stripped label will have the original label lenght at most */
   stripped_label = temp = g_new (gchar, strlen(label) + 1);