Implement in-place mutation operators for MutableSet, MutableList

Implemented in-place mutation operators ``__ior__``, ``__iand__``,
``__ixor__`` and ``__isub__`` for :class:`.mutable.MutableSet`
and ``__iadd__`` for :class:`.mutable.MutableList` so that change
events are fired off when these mutator methods are used to alter the
collection.

Change-Id: Ib357a96d3b06c5deb6b53eb304a8b9f1dc9e9ede
Fixes: #3853

1 files changed, 20 insertions, 0 deletions

diff --git a/lib/sqlalchemy/ext/mutable.py b/lib/sqlalchemy/ext/mutable.py
index ccaeb6aa3..b72303bc8 100644
--- a/lib/sqlalchemy/ext/mutable.py
+++ b/lib/sqlalchemy/ext/mutable.py
@@ -806,6 +806,10 @@ class MutableList(Mutable, list):
         list.extend(self, x)
         self.changed()
 
+    def __iadd__(self, x):
+        self.extend(x)
+        return self
+
     def insert(self, i, x):
         list.insert(self, i, x)
         self.changed()
@@ -885,6 +889,22 @@ class MutableSet(Mutable, set):
         set.symmetric_difference_update(self, *arg)
         self.changed()
 
+    def __ior__(self, other):
+        self.update(other)
+        return self
+
+    def __iand__(self, other):
+        self.intersection_update(other)
+        return self
+
+    def __ixor__(self, other):
+        self.symmetric_difference_update(other)
+        return self
+
+    def __isub__(self, other):
+        self.difference_update(other)
+        return self
+
     def add(self, elem):
         set.add(self, elem)
         self.changed()