hgweb: consume generator inside context manager (issue4756)
authorGregory Szorc <gregory.szorc@gmail.com>
Sat, 12 Sep 2015 12:16:39 -0700
changeset 26247 7df5d4760873
parent 26246 bf81b696b8f4
child 26248 99b6afff09ae
hgweb: consume generator inside context manager (issue4756) If code inside a context manager returns a generator, the context manager exits before the generator is iterated. hgweb was using a context manager to control thread safe access to a localrepository instance. But it was returning a generator, so there was a race condition between a previous request streaming a response to the client and a new request obtaining the released but in use repository. By iterating the generator inside the context manager, we ensure we don't release the repo instance until after the response has finished. With this change, hgweb finally appears to have full localrepository isolation between threads. I can no longer reproduce the 2 exceptions reported in issue4756. test-hgweb-non-interactive.t has been modified to consume the output of calling into a WSGI application. Without this, execution of the WSGI application stalls because of the added yield statement.
mercurial/hgweb/hgweb_mod.py
tests/test-hgweb-non-interactive.t
--- a/mercurial/hgweb/hgweb_mod.py	Thu Aug 27 14:46:26 2015 -0400
+++ b/mercurial/hgweb/hgweb_mod.py	Sat Sep 12 12:16:39 2015 -0700
@@ -275,7 +275,8 @@
         should be using instances of this class as the WSGI application.
         """
         with self._obtainrepo() as repo:
-            return self._runwsgi(req, repo)
+            for r in self._runwsgi(req, repo):
+                yield r
 
     def _runwsgi(self, req, repo):
         rctx = requestcontext(self, repo)
--- a/tests/test-hgweb-non-interactive.t	Thu Aug 27 14:46:26 2015 -0400
+++ b/tests/test-hgweb-non-interactive.t	Sat Sep 12 12:16:39 2015 -0700
@@ -58,7 +58,8 @@
   > }
   > 
   > i = hgweb('.')
-  > i(env, startrsp)
+  > for c in i(env, startrsp):
+  >     pass
   > print '---- ERRORS'
   > print errors.getvalue()
   > print '---- OS.ENVIRON wsgi variables'