[glib] g_variant_get_child(): flatten-first logic on '&'

[Ryan Lortie <desrt src gnome org>]

commit 56b164a19566a63dda23d48a93b91875d89c9fde
Author: Ryan Lortie <desrt desrt ca>
Date:   Mon Sep 21 16:54:49 2015 -0400

    g_variant_get_child(): flatten-first logic on '&'
    
    Copy the flatten-first logic from g_variant_get(), and for the same
    reason: if the user is requesting a direct pointer access to a
    tree-based child inside of argument to this function then that child
    could disappear later.
    
    Forcing serialisation means that the pointer will remain valid as long
    as the passed-in instance exists, which is the usual expectation with
    GVariant API.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=755374

 glib/gvariant.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/glib/gvariant.c b/glib/gvariant.c
index a9c34d4..85bb1ca 100644
--- a/glib/gvariant.c
+++ b/glib/gvariant.c
@@ -5446,6 +5446,10 @@ g_variant_get_child (GVariant    *value,
   GVariant *child;
   va_list ap;
 
+  /* if any direct-pointer-access formats are in use, flatten first */
+  if (strchr (format_string, '&'))
+    g_variant_get_data (value);
+
   child = g_variant_get_child_value (value, index_);
   g_return_if_fail (valid_format_string (format_string, TRUE, child));