--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/components/mercurial/patches/demandimport.patch	Mon Feb 22 14:29:22 2016 -0800
@@ -0,0 +1,34 @@
+Mercurial's demandload system is incompatible with sqlalchemy.
+
+This was reported upstream as
+
+    https://bz.mercurial-scm.org/show_bug.cgi?id=5085
+
+and is available in the upstream repository in changesets c25e3fd38ff1 and
+9ff7261cc0f5.
+
+diff --git a/mercurial/demandimport.py b/mercurial/demandimport.py
+--- a/mercurial/demandimport.py
++++ b/mercurial/demandimport.py
+@@ -174,7 +174,12 @@ def _demandimport(name, globals=None, lo
+             """
+             symbol = getattr(mod, attr, nothing)
+             if symbol is nothing:
+-                symbol = _demandmod(attr, mod.__dict__, locals, level=1)
++                mn = '%s.%s' % (mod.__name__, attr)
++                if mn in ignore:
++                    importfunc = _origimport
++                else:
++                    importfunc = _demandmod
++                symbol = importfunc(attr, mod.__dict__, locals, level=1)
+                 setattr(mod, attr, symbol)
+ 
+             # Record the importing module references this symbol so we can
+@@ -250,6 +255,7 @@ ignore = [
+     '_sre', # issue4920
+     'rfc822',
+     'mimetools',
++    'sqlalchemy.events', # has import-time side effects (issue5085)
+     # setuptools 8 expects this module to explode early when not on windows
+     'distutils.msvc9compiler'
+     ]