[glib/mcatanzaro/#2020] Fix crash caused by g_network_monitor_base_add_network()

[Michael Catanzaro <mcatanzaro src gnome org>]

commit 394a72bc1124ed279e51922b9d81bf24e8419020
Author: Michael Catanzaro <mcatanzaro gnome org>
Date:   Mon Jan 27 16:20:20 2020 -0600

    Fix crash caused by g_network_monitor_base_add_network()
    
    This avoids a crash when starting Evolution, and fixes the
    network-monitor and network-monitor-race test cases on my developer
    workstation. (I assume the CI is not crashing due to lack of network
    access there.)
    
    Problem is that if a network already exists in the networks table,
    g_hash_table_add() "destroys" (unrefs) it before adding the new one
    (which we failed to ref before adding). This means we just accidentally
    lost a ref. In practice, the network gets unexpectedly destroyed here
    before returning.
    
    Fixes #2020

 gio/gnetworkmonitorbase.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)
---
diff --git a/gio/gnetworkmonitorbase.c b/gio/gnetworkmonitorbase.c
index be6ec7277..d503759c1 100644
--- a/gio/gnetworkmonitorbase.c
+++ b/gio/gnetworkmonitorbase.c
@@ -496,11 +496,9 @@ void
 g_network_monitor_base_add_network (GNetworkMonitorBase *monitor,
                                     GInetAddressMask    *network)
 {
-  if (!g_hash_table_add (monitor->priv->networks, network))
+  if (!g_hash_table_add (monitor->priv->networks, g_object_ref (network)))
     return;
 
-  g_object_ref (network);  /* for the element now stored in the hash table */
-
   if (g_inet_address_mask_get_length (network) == 0)
     {
       switch (g_inet_address_mask_get_family (network))