ndb.objects.interface: fix altnames before rename

If the new name is in altnames, remove it from there first.

Bug-Url: #1178

pyroute2/ndb/objects/interface.py

@@ -862,6 +862,8 @@ def __setitem__(self, key, value):
         if key == 'peer':
             dict.__setitem__(self, key, value)
         elif key == 'ifname':
+            if value in self['alt_ifname_list']:
+                self.del_altname(value)
             if key in self and self.old_ifname is None:
                 self.old_ifname = self[key]
             super(Interface, self).__setitem__(key, value)
@@ -984,9 +986,17 @@ def make_req(self, prime):
         return req
 
     @check_auth('obj:modify')
-    def apply_altnames(self, alt_ifname_setup, old_ifname=None):
-        alt_ifname_remove = set(self['alt_ifname_list']) - alt_ifname_setup
-        alt_ifname_add = alt_ifname_setup - set(self['alt_ifname_list'])
+    def apply_altnames(
+        self, alt_ifname_setup, alt_ifname_current, old_ifname=None
+    ):
+        if alt_ifname_current is None:
+            # load the current state
+            self.load_from_system()
+            self.load_sql(set_state=False)
+            alt_ifname_current = set(self['alt_ifname_list'])
+
+        alt_ifname_remove = alt_ifname_current - alt_ifname_setup
+        alt_ifname_add = alt_ifname_setup - alt_ifname_current
         for ifname in alt_ifname_remove:
             self.sources[self['target']].api(
                 'link', 'property_del', index=self['index'], altname=ifname
@@ -995,6 +1005,7 @@ def apply_altnames(self, alt_ifname_setup, old_ifname=None):
             self.sources[self['target']].api(
                 'link', 'property_add', index=self['index'], altname=ifname
             )
+        # reload alt ifnames from the system to check the state
         self.load_from_system()
         self.load_sql(set_state=False)
         if old_ifname is not None and old_ifname in self['alt_ifname_list']:
@@ -1012,9 +1023,15 @@ def apply(self, rollback=False, req_filter=None, mode='apply'):
         remove = self.state.get() == 'remove'
         alt_ifname_setup = set(self['alt_ifname_list'])
         old_ifname = self.old_ifname if 'ifname' in self.changed else None
-        if 'alt_ifname_list' in self.changed:
-            self.changed.remove('alt_ifname_list')
         try:
+            if (
+                old_ifname
+                and 'index' in self
+                and 'alt_ifname_list' in self.changed
+            ):
+                self.apply_altnames(alt_ifname_setup, None)
+            if 'alt_ifname_list' in self.changed:
+                self.changed.remove('alt_ifname_list')
             super(Interface, self).apply(rollback, req_filter, mode)
             if setns:
                 self.load_value('target', self['net_ns_fd'])
@@ -1023,7 +1040,9 @@ def apply(self, rollback=False, req_filter=None, mode='apply'):
                 if spec:
                     self.state.set('system')
             if not remove:
-                self.apply_altnames(alt_ifname_setup, old_ifname)
+                self.apply_altnames(
+                    alt_ifname_setup, set(self['alt_ifname_list']), old_ifname
+                )
 
         except NetlinkError as e:
             if (