[pypy-svn] r13195 - in pypy/dist/pypy/rpython: . test

[arigo at codespeak.net]

Author: arigo
Date: Wed Jun  8 19:40:41 2005
New Revision: 13195

Modified:
   pypy/dist/pypy/rpython/lltype.py
   pypy/dist/pypy/rpython/test/test_lltype.py
Log:
Problem with hash() of recursive structures.


Modified: pypy/dist/pypy/rpython/lltype.py
==============================================================================
--- pypy/dist/pypy/rpython/lltype.py	(original)
+++ pypy/dist/pypy/rpython/lltype.py	Wed Jun  8 19:40:41 2005
@@ -28,7 +28,6 @@
         items = self.items()
         items.sort()
         return hash(tuple(items))
-    __hash__ = saferecursive(__hash__, 0)
 
 
 class LowLevelType(object):
@@ -40,10 +39,21 @@
         return not (self == other)
 
     def __hash__(self):
+        # cannot use saferecursive() -- see test_lltype.test_hash().
+        # this version uses a compromize between computation time and
+        # collision-avoidance that can be customized if needed.
+        try:
+            if TLS.nested_hash_level >= 3:
+                return 0
+        except AttributeError:
+            TLS.nested_hash_level = 0
         items = self.__dict__.items()
         items.sort()
-        return hash((self.__class__,) + tuple(items))
-    __hash__ = saferecursive(__hash__, 0)
+        TLS.nested_hash_level += 1
+        try:
+            return hash((self.__class__,) + tuple(items))
+        finally:
+            TLS.nested_hash_level -= 1
 
     def __repr__(self):
         return '<%s>' % (self,)

Modified: pypy/dist/pypy/rpython/test/test_lltype.py
==============================================================================
--- pypy/dist/pypy/rpython/test/test_lltype.py	(original)
+++ pypy/dist/pypy/rpython/test/test_lltype.py	Wed Jun  8 19:40:41 2005
@@ -241,3 +241,12 @@
     S = Struct('s')
     p0 = nullptr(S)
     assert not p0
+
+def test_hash():
+    S = ForwardReference()
+    S.become(Struct('S', ('p', Ptr(S))))
+    assert S == S
+    S1 = Struct('S', ('p', Ptr(S)))
+    assert S1 == S
+    assert S == S1
+    assert hash(S1) == hash(S)