ceval.c/do_raise(): Tighten the test to disallow raising an instance of

tim-one · tim-one · commit afb2c80b2989 · 2002-04-18T18:06:20.000Z
a str subclass.

test_descr.py/string_exceptions():  New sub-test.

For 2.3 only.  Guido doesn't want this backported.
diff --git a/Lib/test/test_descr.py b/Lib/test/test_descr.py
@@ -2974,6 +2974,31 @@ class NewClass(object):
     vereq(NewClass.__doc__, 'object=None; type=NewClass')
     vereq(NewClass().__doc__, 'object=NewClass instance; type=NewClass')
 
+def string_exceptions():
+    if verbose:
+        print "Testing string exceptions ..."
+
+    # Ensure builtin strings work OK as exceptions.
+    astring = "An exception string."
+    try:
+        raise astring
+    except astring:
+        pass
+    else:
+        raise TestFailed, "builtin string not usable as exception"
+
+    # Ensure string subclass instances do not.
+    class MyStr(str):
+        pass
+
+    newstring = MyStr("oops -- shouldn't work")
+    try:
+        raise newstring
+    except TypeError:
+        pass
+    except:
+        raise TestFailed, "string subclass allowed as exception"
+
 def test_main():
     class_docstrings()
     lists()
@@ -3039,6 +3064,7 @@ def test_main():
     funnynew()
     imulbug()
     docdescriptor()
+    string_exceptions()
     if verbose: print "All OK"
 
 if __name__ == "__main__":
diff --git a/Python/ceval.c b/Python/ceval.c
@@ -2743,7 +2743,10 @@ do_raise(PyObject *type, PyObject *value, PyObject *tb)
 		Py_DECREF(tmp);
 	}
 
-	if (PyString_Check(type))
+	if (PyString_CheckExact(type))
+		/* Raising builtin string is deprecated but still allowed --
+		 * do nothing.  Raising an instance of a new-style str
+		 * subclass is right out. */
 		;
 
 	else if (PyClass_Check(type))

Original file line number	Diff line number	Diff line change
`@@ -2743,7 +2743,10 @@ do_raise(PyObject type, PyObject value, PyObject *tb)`
`2743`	`2743`	`Py_DECREF(tmp);`
`2744`	`2744`	`}`
`2745`	`2745`
`2746`		`- if (PyString_Check(type))`
	`2746`	`+ if (PyString_CheckExact(type))`
	`2747`	`+ /* Raising builtin string is deprecated but still allowed --`
	`2748`	`+ * do nothing. Raising an instance of a new-style str`
	`2749`	`+ * subclass is right out. */`
`2747`	`2750`	`;`
`2748`	`2751`
`2749`	`2752`	`else if (PyClass_Check(type))`