Merged revisions 67689 via svnmerge from

svn+ssh://pythondev@svn.python.org/python/branches/py3k

................
  r67689 | amaury.forgeotdarc | 2008-12-11 00:49:33 +0100 (jeu., 11 déc. 2008) | 13 lines

  Merged revisions 67688 via svnmerge from
  svn+ssh://pythondev@svn.python.org/python/trunk

  ........
    r67688 | amaury.forgeotdarc | 2008-12-11 00:22:49 +0100 (jeu., 11 déc. 2008) | 6 lines

    #4559: When a context manager's __exit__() method returns an object whose
    conversion to bool raises an exception, 'with' loses that exception.

    Reviewed by Jeffrey Yasskin.
    Already ported to 2.5, will port to 2.6 and 3.0
  ........
................

diff --git a/Lib/test/test_with.py b/Lib/test/test_with.py
index 43f327122854cd7502c19dfd86ccc66674db3b2a..b192429cf719780988ad842661c419ba1e3c8547 100644 (file)
--- a/Lib/test/test_with.py
+++ b/Lib/test/test_with.py
@@ -505,6 +505,36 @@ class ExceptionalTestCase(ContextmanagerAssertionMixin, unittest.TestCase):
 
         self.assertRaises(GeneratorExit, shouldThrow)
 
+    def testErrorsInBool(self):
+        # issue4589: __exit__ return code may raise an exception
+        # when looking at its truth value.
+
+        class cm(object):
+            def __init__(self, bool_conversion):
+                class Bool:
+                    def __bool__(self):
+                        return bool_conversion()
+                self.exit_result = Bool()
+            def __enter__(self):
+                return 3
+            def __exit__(self, a, b, c):
+                return self.exit_result
+
+        def trueAsBool():
+            with cm(lambda: True):
+                self.fail("Should NOT see this")
+        trueAsBool()
+
+        def falseAsBool():
+            with cm(lambda: False):
+                self.fail("Should raise")
+        self.assertRaises(AssertionError, falseAsBool)
+
+        def failAsBool():
+            with cm(lambda: 1//0):
+                self.fail("Should NOT see this")
+        self.assertRaises(ZeroDivisionError, failAsBool)
+
 
 class NonLocalFlowControlTestCase(unittest.TestCase):
 

diff --git a/Misc/NEWS b/Misc/NEWS
index 61e2263cbafdbbdf091f430a69edcfc5e5796553..3dbd1eea2bf92e47fa486019039d38b50c5418b5 100644 (file)
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -12,6 +12,9 @@ What's New in Python 3.0.1?
 Core and Builtins
 -----------------
 
+- Issue #4597: Fixed exception handling when the __exit__ function of a
+  context manager returns a value that cannot be converted to a bool.
+
 - Issue #4533: File read operation was dreadfully slow due to a slowly
   growing read buffer. Fixed by using the same growth rate algorithm as
   Python 2.x.

diff --git a/Python/ceval.c b/Python/ceval.c
index dc4276b1bb64ce3eab0f1feefaabcbf8351bc5a5..f58a55d7baf4225140228335e72ef9d5293db4ef 100644 (file)
--- a/Python/ceval.c
+++ b/Python/ceval.c
@@ -2181,7 +2181,17 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
                        Py_DECREF(exit_func);
                        if (x == NULL)
                                break; /* Go to error exit */
-                       if (u != Py_None && PyObject_IsTrue(x)) {
+
+                       if (u != Py_None)
+                               err = PyObject_IsTrue(x);
+                       else
+                               err = 0;
+                       Py_DECREF(x);
+
+                       if (err < 0)
+                               break; /* Go to error exit */
+                       else if (err > 0) {
+                               err = 0;
                                /* There was an exception and a True return */
                                STACKADJ(-2);
                                SET_TOP(PyLong_FromLong((long) WHY_SILENCED));
@@ -2189,7 +2199,6 @@ PyEval_EvalFrameEx(PyFrameObject *f, int throwflag)
                                Py_DECREF(v);
                                Py_DECREF(w);
                        }
-                       Py_DECREF(x);
                        PREDICT(END_FINALLY);
                        break;
                }