Restore the API for async_creation_runner in all cases

Fixed regression in 0.7.0 caused by 🎫`136` where the assumed
arguments for the :paramref:`.CacheRegion.async_creation_runner` expanded to
include the new :paramref:`.CacheRegion.get_or_create.creator_args`
parameter, as it was not tested that the async runner would be implicitly
called with these arguments when the :meth:`.CacheRegion.cache_on_arguments`
decorator was used.  The exact signature of ``async_creation_runner`` is
now restored to have the same arguments in all cases.

Fixes: #139
Change-Id: I91c95b183e01d1bbe1c42b3375fcfa65866cc97d

docs/build/unreleased/139.rst

@@ -0,0 +1,12 @@
+.. change::
+   :tags: bug, region
+   :tickets: 139
+
+   Fixed regression in 0.7.0 caused by :ticket:`136` where the assumed
+   arguments for the :paramref:`.CacheRegion.async_creation_runner` expanded to
+   include the new :paramref:`.CacheRegion.get_or_create.creator_args`
+   parameter, as it was not tested that the async runner would be implicitly
+   called with these arguments when the :meth:`.CacheRegion.cache_on_arguments`
+   decorator was used.  The exact signature of ``async_creation_runner`` is
+   now restored to have the same arguments in all cases.
+

dogpile/cache/region.py

@@ -862,12 +862,12 @@ def gen_value():
         if self.async_creation_runner:
             def async_creator(mutex):
                 if creator_args:
-                    return self.async_creation_runner(
-                        self, orig_key, creator, mutex,
-                        creator_args=creator_args)
+                    @wraps(creator)
+                    def go():
+                        return creator(*creator_args[0], **creator_args[1])
                 else:
-                    return self.async_creation_runner(
-                        self, orig_key, creator, mutex)
+                    go = creator
+                return self.async_creation_runner(self, orig_key, go, mutex)
         else:
             async_creator = None
 

tests/cache/test_region.py

@@ -11,6 +11,7 @@
 import time
 import datetime
 import itertools
+import mock
 from collections import defaultdict
 from ._fixtures import MockBackend
 
@@ -528,6 +529,79 @@ def _region(self, init_args={}, config_args={}, backend="mock"):
         return reg
 
 
+class AsyncCreatorTest(TestCase):
+    def _fixture(self):
+
+        def async_creation_runner(cache, somekey, creator, mutex):
+            try:
+                value = creator()
+                cache.set(somekey, value)
+            finally:
+                mutex.release()
+
+        return mock.Mock(side_effect=async_creation_runner)
+
+    def test_get_or_create(self):
+        acr = self._fixture()
+        reg = CacheRegion(async_creation_runner=acr)
+        reg.configure("mock", expiration_time=.2)
+
+        def some_value():
+            return "some value"
+
+        def some_new_value():
+            return "some new value"
+
+        eq_(reg.get_or_create("some key", some_value), "some value")
+        time.sleep(.5)
+        eq_(
+            reg.get_or_create("some key", some_new_value),
+            "some value")
+        eq_(
+            reg.get_or_create("some key", some_new_value),
+            "some new value")
+        eq_(
+            acr.mock_calls, [
+                mock.call(reg, "some key",
+                          some_new_value, reg._mutex("some key"))
+            ])
+
+    def test_fn_decorator(self):
+        acr = self._fixture()
+        reg = CacheRegion(async_creation_runner=acr)
+        reg.configure("mock", expiration_time=5)
+
+        canary = mock.Mock()
+
+        @reg.cache_on_arguments()
+        def go(x, y):
+            canary(x, y)
+            return x + y
+
+        eq_(go(1, 2), 3)
+        eq_(go(1, 2), 3)
+
+        eq_(canary.mock_calls, [mock.call(1, 2)])
+
+        eq_(go(3, 4), 7)
+
+        eq_(canary.mock_calls, [mock.call(1, 2), mock.call(3, 4)])
+
+        reg.invalidate(hard=False)
+
+        eq_(go(1, 2), 3)
+
+        eq_(canary.mock_calls, [
+            mock.call(1, 2), mock.call(3, 4), mock.call(1, 2)])
+
+        eq_(
+            acr.mock_calls, [
+                mock.call(reg, "tests.cache.test_region:go|1 2",
+                          mock.ANY,
+                          reg._mutex("tests.cache.test_region:go|1 2"))
+            ])
+
+
 class ProxyBackendTest(TestCase):
 
     class GetCounterProxy(ProxyBackend):