From: Mike Bayer <mike_mp@zzzcomputing.com>
Date: Thu, 13 Nov 2014 18:17:38 +0000 (-0500)
Subject: - Fixed a leak which would occur in the unsupported and highly
X-Git-Tag: rel_1_0_0~19^2~22
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=026449c15ff35a9b89c2ca591d3e3cc791857272;p=thirdparty%2Fsqlalchemy%2Fsqlalchemy.git

- Fixed a leak which would occur in the unsupported and highly
non-recommended use case of replacing a relationship on a fixed
mapped class many times, referring to an arbitrarily growing number of
target mappers.  A warning is emitted when the old relationship is
replaced, however if the mapping were already used for querying, the
old relationship would still be referenced within some registries.
fixes #3251
---

diff --git a/doc/build/changelog/changelog_09.rst b/doc/build/changelog/changelog_09.rst
index 66a7da8dab..abf564875d 100644
--- a/doc/build/changelog/changelog_09.rst
+++ b/doc/build/changelog/changelog_09.rst
@@ -13,6 +13,18 @@
 .. changelog::
     :version: 0.9.9
 
+    .. change::
+        :tags: bug, orm
+        :versions: 1.0.0
+        :tickets: 3251
+
+        Fixed a leak which would occur in the unsupported and highly
+        non-recommended use case of replacing a relationship on a fixed
+        mapped class many times, referring to an arbitrarily growing number of
+        target mappers.  A warning is emitted when the old relationship is
+        replaced, however if the mapping were already used for querying, the
+        old relationship would still be referenced within some registries.
+
     .. change::
         :tags: bug, sql
         :versions: 1.0.0
diff --git a/lib/sqlalchemy/orm/mapper.py b/lib/sqlalchemy/orm/mapper.py
index 7e88ba161f..863dab5cbf 100644
--- a/lib/sqlalchemy/orm/mapper.py
+++ b/lib/sqlalchemy/orm/mapper.py
@@ -1581,6 +1581,8 @@ class Mapper(InspectionAttr):
                           self,
                           prop,
                       ))
+            oldprop = self._props[key]
+            self._path_registry.pop(oldprop, None)
 
         self._props[key] = prop
 
diff --git a/test/aaa_profiling/test_memusage.py b/test/aaa_profiling/test_memusage.py
index f4bce6b01b..63883daac6 100644
--- a/test/aaa_profiling/test_memusage.py
+++ b/test/aaa_profiling/test_memusage.py
@@ -658,6 +658,32 @@ class MemUsageTest(EnsureZeroed):
                 row[t.c.x]
         go()
 
+    def test_many_discarded_relationships(self):
+        """a use case that really isn't supported, nonetheless we can
+        guard against memleaks here so why not"""
+
+        m1 = MetaData()
+        t1 = Table('t1', m1, Column('id', Integer, primary_key=True))
+        t2 = Table(
+            't2', m1, Column('id', Integer, primary_key=True),
+            Column('t1id', ForeignKey('t1.id')))
+
+        class T1(object):
+            pass
+        t1_mapper = mapper(T1, t1)
+
+        @testing.emits_warning()
+        @profile_memory()
+        def go():
+            class T2(object):
+                pass
+            t2_mapper = mapper(T2, t2)
+            t1_mapper.add_property("bar", relationship(t2_mapper))
+            s1 = Session()
+            # this causes the path_registry to be invoked
+            s1.query(t1_mapper)._compile_context()
+        go()
+
     # fails on newer versions of pysqlite due to unusual memory behvior
     # in pysqlite itself. background at:
     # http://thread.gmane.org/gmane.comp.python.db.pysqlite.user/2290