[telepathy-gabble/master] Don't crash on an empty <nick/> node.

[Will Thompson]

Fixes fd.o #21817
---
 src/conn-aliasing.c                   |   15 ++++++++++++---
 tests/twisted/vcard/test-alias-pep.py |   29 +++++++++++++++++++++++++++--
 2 files changed, 39 insertions(+), 5 deletions(-)

diff --git a/src/conn-aliasing.c b/src/conn-aliasing.c
index 8d02a0d..4dd7759 100644
--- a/src/conn-aliasing.c
+++ b/src/conn-aliasing.c
@@ -607,14 +607,23 @@ _grab_nickname (GabbleConnection *self,
       _cache_negatively (self, handle);
       return FALSE;
     }
-  nickname = lm_message_node_get_value (node);
 
+  nickname = lm_message_node_get_value (node);
   old = tp_handle_get_qdata (contact_handles, handle, quark);
 
   if (tp_strdiff (old, nickname))
     {
-      tp_handle_set_qdata (contact_handles, handle, quark, g_strdup (nickname),
-          g_free);
+      if (nickname == NULL)
+        {
+          DEBUG ("got empty <nick/> node, caching as NO_ALIAS");
+          _cache_negatively (self, handle);
+        }
+      else
+        {
+          tp_handle_set_qdata (contact_handles, handle, quark, g_strdup (nickname),
+              g_free);
+        }
+
       gabble_conn_aliasing_nickname_updated ((GObject *) self, handle, self);
     }
   return TRUE;
diff --git a/tests/twisted/vcard/test-alias-pep.py b/tests/twisted/vcard/test-alias-pep.py
index 0375061..43f4b26 100644
--- a/tests/twisted/vcard/test-alias-pep.py
+++ b/tests/twisted/vcard/test-alias-pep.py
@@ -3,8 +3,8 @@
 Test PEP alias support.
 """
 
-from servicetest import call_async, EventPattern, assertEquals
-from gabbletest import exec_test, make_result_iq, acknowledge_iq
+from servicetest import call_async, EventPattern, assertEquals, assertLength
+from gabbletest import exec_test, make_result_iq, acknowledge_iq, elem
 
 import constants as cs
 import ns
@@ -43,6 +43,31 @@ def test(q, bus, conn, stream):
     # A second request should be satisfied from the cache.
     assertEquals(['Bobby'], conn.Aliasing.RequestAliases([handle]))
 
+    # Bobby grows up, decides he hates his nickname.
+    # This is a regression test for
+    # <https://bugs.freedesktop.org/show_bug.cgi?id=21817>, where this would
+    # crash Gabble.
+    message = elem('message')(
+        elem((ns.PUBSUB + "#event"), 'event')(
+            elem('items', node=ns.NICK)(
+                elem('item')(
+                    elem(ns.NICK, 'nick')
+                )
+            )
+        )
+    )
+    message['from'] = 'bob at foo.com' # thanks, Python
+    stream.send(message.toXml())
+
+    event = q.expect('dbus-signal', signal='AliasesChanged')
+    aliases = event.args[0]
+    assertLength(1, aliases)
+    h, a = aliases[0]
+    assertEquals(handle, h)
+    # The contact explicitly cleared their PEP nick; Gabble should fall back to
+    # their JID.
+    assertEquals(a, 'bob at foo.com')
+
     conn.Disconnect()
     q.expect('dbus-signal', signal='StatusChanged',
         args=[cs.CONN_STATUS_DISCONNECTED, cs.CSR_REQUESTED]),
-- 
1.5.6.5