[pypy-commit] pypy default: Issue #781: improve the error message.

[arigo]

Author: Armin Rigo <arigo at tunes.org>
Branch: 
Changeset: r45935:ea1d8b0f01bd
Date: 2011-07-24 14:23 +0200
http://bitbucket.org/pypy/pypy/changeset/ea1d8b0f01bd/

Log:	Issue #781: improve the error message.

diff --git a/pypy/interpreter/pyopcode.py b/pypy/interpreter/pyopcode.py
--- a/pypy/interpreter/pyopcode.py
+++ b/pypy/interpreter/pyopcode.py
@@ -905,16 +905,15 @@
 
     def SETUP_WITH(self, offsettoend, next_instr):
         w_manager = self.peekvalue()
+        w_enter = self.space.lookup(w_manager, "__enter__")
         w_descr = self.space.lookup(w_manager, "__exit__")
-        if w_descr is None:
-            raise OperationError(self.space.w_AttributeError,
-                                 self.space.wrap("__exit__"))
+        if w_enter is None or w_descr is None:
+            typename = self.space.type(w_manager).getname(self.space)
+            raise operationerrfmt(self.space.w_AttributeError,
+                "'%s' object is not a context manager"
+                " (no __enter__/__exit__ method)", typename)
         w_exit = self.space.get(w_descr, w_manager)
         self.settopvalue(w_exit)
-        w_enter = self.space.lookup(w_manager, "__enter__")
-        if w_enter is None:
-            raise OperationError(self.space.w_AttributeError,
-                                 self.space.wrap("__enter__"))
         w_result = self.space.get_and_call_function(w_enter, w_manager)
         block = WithBlock(self, next_instr + offsettoend)
         self.append_block(block)