#17413: make sure settrace funcs get passed exception instances for 'value'.

bitdancer · bitdancer · commit 3583761bcd3e · 2013-04-19T12:56:57.000-04:00
Patch by Ingrid Cheung and Brendan McLoughlin.
diff --git a/Lib/test/test_sys_settrace.py b/Lib/test/test_sys_settrace.py
@@ -458,6 +458,29 @@ def g(frame, why, extra):
             self.fail("exception not propagated")
 
 
+    def test_exception_arguments(self):
+        def f():
+            x = 0
+            # this should raise an error
+            x.no_such_attr
+        def g(frame, event, arg):
+            if (event == 'exception'):
+                type, exception, trace = arg
+                self.assertIsInstance(exception, Exception)
+            return g
+
+        existing = sys.gettrace()
+        try:
+            sys.settrace(g)
+            try:
+                f()
+            except AttributeError:
+                # this is expected
+                pass
+        finally:
+            sys.settrace(existing)
+
+
 # 'Jump' tests: assigning to frame.f_lineno within a trace function
 # moves the execution position - it's how debuggers implement a Jump
 # command (aka. "Set next statement").
diff --git a/Misc/ACKS b/Misc/ACKS
@@ -208,6 +208,7 @@ David Chaum
 Nicolas Chauvat
 Jerry Chen
 Michael Chermside
+Ingrid Cheung
 Albert Chin-A-Young
 Adal Chiriliuc
 Matt Chisholm
@@ -786,6 +787,7 @@ Chris McDonough
 Greg McFarlane
 Alan McIntyre
 Michael McLay
+Brendan McLoughlin
 Mark Mc Mahon
 Gordon McMillan
 Andrew McNamara
diff --git a/Misc/NEWS b/Misc/NEWS
@@ -12,6 +12,10 @@ What's New in Python 3.3.2?
 Core and Builtins
 -----------------
 
+- Issue #17413: sys.settrace callbacks were being passed a string instead of an
+  exception instance for the 'value' element of the arg tuple if the exception
+  originated from C code; now an exception instance is always provided.
+
 - Issue #17782: Fix undefined behaviour on platforms where
   ``struct timespec``'s "tv_nsec" member is not a C long.
 
diff --git a/Python/ceval.c b/Python/ceval.c
@@ -3712,6 +3712,7 @@ call_exc_trace(Py_tracefunc func, PyObject *self, PyFrameObject *f)
         value = Py_None;
         Py_INCREF(value);
     }
+    PyErr_NormalizeException(&type, &value, &traceback);
     arg = PyTuple_Pack(3, type, value, traceback);
     if (arg == NULL) {
         PyErr_Restore(type, value, traceback);

Original file line number	Diff line number	Diff line change
`@@ -3712,6 +3712,7 @@ call_exc_trace(Py_tracefunc func, PyObject self, PyFrameObject f)`
`3712`	`3712`	`value = Py_None;`
`3713`	`3713`	`Py_INCREF(value);`
`3714`	`3714`	`}`
	`3715`	`+ PyErr_NormalizeException(&type, &value, &traceback);`
`3715`	`3716`	`arg = PyTuple_Pack(3, type, value, traceback);`
`3716`	`3717`	`if (arg == NULL) {`
`3717`	`3718`	`PyErr_Restore(type, value, traceback);`