Fix #159: Pass self to @cachedmethod key function.

src/cachetools/__init__.py

@@ -22,7 +22,11 @@
 import random
 import time
 
-from .keys import hashkey
+from .keys import hashkey as _defaultkey
+
+
+def _methodkey(_, *args, **kwargs):
+    return _defaultkey(*args, **kwargs)
 
 
 class _DefaultSize:
@@ -615,7 +619,7 @@ def __getitem(self, key):
         return value
 
 
-def cached(cache, key=hashkey, lock=None):
+def cached(cache, key=_defaultkey, lock=None):
     """Decorator to wrap a function with a memoizing callable that saves
     results in a cache.
 
@@ -664,7 +668,7 @@ def wrapper(*args, **kwargs):
     return decorator
 
 
-def cachedmethod(cache, key=hashkey, lock=None):
+def cachedmethod(cache, key=_methodkey, lock=None):
     """Decorator to wrap a class or instance method with a memoizing
     callable that saves results in a cache.
 
@@ -677,7 +681,7 @@ def wrapper(self, *args, **kwargs):
                 c = cache(self)
                 if c is None:
                     return method(self, *args, **kwargs)
-                k = key(*args, **kwargs)
+                k = key(self, *args, **kwargs)
                 try:
                     return c[k]
                 except KeyError:
@@ -695,7 +699,7 @@ def wrapper(self, *args, **kwargs):
                 c = cache(self)
                 if c is None:
                     return method(self, *args, **kwargs)
-                k = key(*args, **kwargs)
+                k = key(self, *args, **kwargs)
                 try:
                     with lock(self):
                         return c[k]

tests/test_method.py

@@ -21,10 +21,6 @@ def get_typed(self, value):
         self.count += 1
         return count
 
-    # https://github.com/tkem/cachetools/issues/107
-    def __hash__(self):
-        raise TypeError("unhashable type")
-
 
 class Locked:
     def __init__(self, cache):
@@ -42,6 +38,23 @@ def __exit__(self, *exc):
         pass
 
 
+class Unhashable:
+    def __init__(self, cache):
+        self.cache = cache
+
+    @cachedmethod(operator.attrgetter("cache"))
+    def get_default(self, value):
+        return value
+
+    @cachedmethod(operator.attrgetter("cache"), key=keys.hashkey)
+    def get_hashkey(self, value):
+        return value
+
+    # https://github.com/tkem/cachetools/issues/107
+    def __hash__(self):
+        raise TypeError("unhashable type")
+
+
 class CachedMethodTest(unittest.TestCase):
     def test_dict(self):
         cached = Cached({})
@@ -163,3 +176,12 @@ def test_locked_nospace(self):
         self.assertEqual(cached.get(1), 5)
         self.assertEqual(cached.get(1.0), 7)
         self.assertEqual(cached.get(1.0), 9)
+
+    def test_unhashable(self):
+        cached = Unhashable(LRUCache(maxsize=0))
+
+        self.assertEqual(cached.get_default(0), 0)
+        self.assertEqual(cached.get_default(1), 1)
+
+        with self.assertRaises(TypeError):
+            cached.get_hashkey(0)