[pypy-svn] r59810 - in pypy/trunk/pypy/annotation: . test

[arigo at codespeak.net]

Author: arigo
Date: Sat Nov  8 16:34:23 2008
New Revision: 59810

Modified:
   pypy/trunk/pypy/annotation/test/test_annrpython.py
   pypy/trunk/pypy/annotation/unaryop.py
Log:
Test and fix: yet another of those order-dependant issues
shown by "assert s_value.contains(...)" in the annotator.


Modified: pypy/trunk/pypy/annotation/test/test_annrpython.py
==============================================================================
--- pypy/trunk/pypy/annotation/test/test_annrpython.py	(original)
+++ pypy/trunk/pypy/annotation/test/test_annrpython.py	Sat Nov  8 16:34:23 2008
@@ -3105,7 +3105,22 @@
 
         a = self.RPythonAnnotator()
         py.test.raises(TooLateForChange, a.build_types, f, [])
-        
+
+
+    def test_len_of_empty_list(self):
+        class X:
+            pass
+        def f(n):
+            x = X()
+            x.lst = None
+            if n < 0:   # to showcase a failure of the famous "assert contains"
+                return len(x.lst)
+            x.lst = []
+            return len(x.lst)
+        a = self.RPythonAnnotator()
+        s = a.build_types(f, [int])
+        assert s.const == 0
+
 
 def g(n):
     return [0,1,2,n]

Modified: pypy/trunk/pypy/annotation/unaryop.py
==============================================================================
--- pypy/trunk/pypy/annotation/unaryop.py	(original)
+++ pypy/trunk/pypy/annotation/unaryop.py	Sat Nov  8 16:34:23 2008
@@ -668,6 +668,14 @@
         elif not pbc.can_be_None:
             s.const = True
 
+    def len(pbc):
+        if pbc.isNone():
+            # this None could later be generalized into an empty list,
+            # whose length is the constant 0; so let's tentatively answer 0.
+            return immutablevalue(0)
+        else:
+            return SomeObject()    # len() on a pbc? no chance
+
 class __extend__(SomeGenericCallable):
     def call(self, args):
         bookkeeper = getbookkeeper()