From: Amaury Forgeot d'Arc <amauryfa@gmail.com>
Date: Wed, 10 Dec 2008 23:55:09 +0000 (+0000)
Subject: Merged revisions 67689 via svnmerge from
X-Git-Tag: v3.0.1~247
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d8d8253dea866f7681ac8094778f982c0983ed16;p=thirdparty%2FPython%2Fcpython.git

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 43f327122854..b192429cf719 100644
--- 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 61e2263cbafd..3dbd1eea2bf9 100644
--- 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 dc4276b1bb64..f58a55d7baf4 100644
--- 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;
 		}