[people/ms/ipfire-3.x.git] / python / patches / 00170-gc-assertions.patch

diff -up Python-2.7.3/Lib/test/test_gc.py.gc-assertions Python-2.7.3/Lib/test/test_gc.py
--- Python-2.7.3/Lib/test/test_gc.py.gc-assertions	2013-02-20 16:28:20.890536607 -0500
+++ Python-2.7.3/Lib/test/test_gc.py	2013-02-20 16:39:52.720489297 -0500
@@ -1,6 +1,7 @@
 import unittest
-from test.test_support import verbose, run_unittest, start_threads
+from test.test_support import verbose, run_unittest, start_threads, import_module
 import sys
+import sysconfig
 import time
 import gc
 import weakref
@@ -32,6 +33,8 @@ class GC_Detector(object):
         self.wr = weakref.ref(C1055820(666), it_happened)
 
 
+BUILT_WITH_NDEBUG = ('-DNDEBUG' in sysconfig.get_config_vars()['PY_CFLAGS'])
+
 ### Tests
 ###############################################################################
 
@@ -476,6 +479,49 @@ class GCTests(unittest.TestCase):
             # would be damaged, with an empty __dict__.
             self.assertEqual(x, None)
 
+    @unittest.skipIf(BUILT_WITH_NDEBUG,
+                     'built with -NDEBUG')
+    def test_refcount_errors(self):
+        # Verify the "handling" of objects with broken refcounts
+ 
+        import_module("ctypes") #skip if not supported
+
+        import subprocess
+        code = '''if 1:
+        a = []
+        b = [a]
+
+        # Simulate the refcount of "a" being too low (compared to the
+        # references held on it by live data), but keeping it above zero
+        # (to avoid deallocating it):
+        import ctypes
+        ctypes.pythonapi.Py_DecRef(ctypes.py_object(a))
+
+        # The garbage collector should now have a fatal error when it reaches
+        # the broken object:
+        import gc
+        gc.collect()
+        '''
+        p = subprocess.Popen([sys.executable, "-c", code],
+                             stdout=subprocess.PIPE,
+                             stderr=subprocess.PIPE)
+        stdout, stderr = p.communicate()
+        p.stdout.close()
+        p.stderr.close()
+        # Verify that stderr has a useful error message:
+        self.assertRegexpMatches(stderr,
+            b'Modules/gcmodule.c:[0-9]+: visit_decref: Assertion "gc->gc.gc_refs != 0" failed.')
+        self.assertRegexpMatches(stderr,
+            b'refcount was too small')
+        self.assertRegexpMatches(stderr,
+            b'object  : \[\]')
+        self.assertRegexpMatches(stderr,
+            b'type    : list')
+        self.assertRegexpMatches(stderr,
+            b'refcount: 1')
+        self.assertRegexpMatches(stderr,
+            b'address : 0x[0-9a-f]+')
+
 class GCTogglingTests(unittest.TestCase):
     def setUp(self):
         gc.enable()
diff -up Python-2.7.3/Modules/gcmodule.c.gc-assertions Python-2.7.3/Modules/gcmodule.c
--- Python-2.7.3/Modules/gcmodule.c.gc-assertions	2012-04-09 19:07:34.000000000 -0400
+++ Python-2.7.3/Modules/gcmodule.c	2013-02-20 16:28:21.029536600 -0500
@@ -21,6 +21,73 @@
 #include "Python.h"
 #include "frameobject.h"        /* for PyFrame_ClearFreeList */
 
+/* 
+   Define a pair of assertion macros.
+
+   These work like the regular C assert(), in that they will abort the
+   process with a message on stderr if the given condition fails to hold,
+   but compile away to nothing if NDEBUG is defined.
+
+   However, before aborting, Python will also try to call _PyObject_Dump() on
+   the given object.  This may be of use when investigating bugs in which a
+   particular object is corrupt (e.g. buggy a tp_visit method in an extension
+   module breaking the garbage collector), to help locate the broken objects.
+
+   The WITH_MSG variant allows you to supply an additional message that Python
+   will attempt to print to stderr, after the object dump.
+*/
+#ifdef NDEBUG
+/* No debugging: compile away the assertions: */
+#define PyObject_ASSERT_WITH_MSG(obj, expr, msg) ((void)0)
+#else
+/* With debugging: generate checks: */
+#define PyObject_ASSERT_WITH_MSG(obj, expr, msg) \
+  ((expr)                                           \
+   ? (void)(0)                                      \
+   : _PyObject_AssertFailed((obj),                  \
+                            (msg),                  \
+                            (__STRING(expr)),       \
+                            (__FILE__),             \
+                            (__LINE__),             \
+                            (__PRETTY_FUNCTION__)))
+#endif
+
+#define PyObject_ASSERT(obj, expr) \
+  PyObject_ASSERT_WITH_MSG(obj, expr, NULL)
+
+static void _PyObject_AssertFailed(PyObject *,  const char *,
+				   const char *, const char *, int,
+				   const char *);
+
+static void
+_PyObject_AssertFailed(PyObject *obj, const char *msg, const char *expr,
+		       const char *file, int line, const char *function)
+{
+    fprintf(stderr,
+            "%s:%d: %s: Assertion \"%s\" failed.\n",
+            file, line, function, expr);
+    if (msg) {
+        fprintf(stderr, "%s\n", msg);
+    }
+
+    fflush(stderr);
+
+    if (obj) {
+        /* This might succeed or fail, but we're about to abort, so at least
+           try to provide any extra info we can: */
+        _PyObject_Dump(obj);
+    }
+    else {
+        fprintf(stderr, "NULL object\n");
+    }
+
+    fflush(stdout);
+    fflush(stderr);
+
+    /* Terminate the process: */
+    abort();
+}
+
 /* Get an object's GC head */
 #define AS_GC(o) ((PyGC_Head *)(o)-1)
 
@@ -288,7 +355,8 @@ update_refs(PyGC_Head *containers)
 {
     PyGC_Head *gc = containers->gc.gc_next;
     for (; gc != containers; gc = gc->gc.gc_next) {
-        assert(gc->gc.gc_refs == GC_REACHABLE);
+        PyObject_ASSERT(FROM_GC(gc),
+                        gc->gc.gc_refs == GC_REACHABLE);
         gc->gc.gc_refs = Py_REFCNT(FROM_GC(gc));
         /* Python's cyclic gc should never see an incoming refcount
          * of 0:  if something decref'ed to 0, it should have been
@@ -308,7 +376,8 @@ update_refs(PyGC_Head *containers)
          * so serious that maybe this should be a release-build
          * check instead of an assert?
          */
-        assert(gc->gc.gc_refs != 0);
+        PyObject_ASSERT(FROM_GC(gc),
+                        gc->gc.gc_refs != 0);
     }
 }
 
@@ -323,7 +392,9 @@ visit_decref(PyObject *op, void *data)
          * generation being collected, which can be recognized
          * because only they have positive gc_refs.
          */
-        assert(gc->gc.gc_refs != 0); /* else refcount was too small */
+        PyObject_ASSERT_WITH_MSG(FROM_GC(gc),
+                                 gc->gc.gc_refs != 0,
+                                 "refcount was too small");
         if (gc->gc.gc_refs > 0)
             gc->gc.gc_refs--;
     }
@@ -383,9 +454,10 @@ visit_reachable(PyObject *op, PyGC_Head
          * If gc_refs == GC_UNTRACKED, it must be ignored.
          */
          else {
-            assert(gc_refs > 0
-                   || gc_refs == GC_REACHABLE
-                   || gc_refs == GC_UNTRACKED);
+             PyObject_ASSERT(FROM_GC(gc),
+                             gc_refs > 0
+                             || gc_refs == GC_REACHABLE
+                             || gc_refs == GC_UNTRACKED);
          }
     }
     return 0;
@@ -427,7 +499,7 @@ move_unreachable(PyGC_Head *young, PyGC_
              */
             PyObject *op = FROM_GC(gc);
             traverseproc traverse = Py_TYPE(op)->tp_traverse;
-            assert(gc->gc.gc_refs > 0);
+            PyObject_ASSERT(op, gc->gc.gc_refs > 0);
             gc->gc.gc_refs = GC_REACHABLE;
             (void) traverse(op,
                             (visitproc)visit_reachable,
@@ -494,7 +566,8 @@ move_finalizers(PyGC_Head *unreachable,
     for (gc = unreachable->gc.gc_next; gc != unreachable; gc = next) {
         PyObject *op = FROM_GC(gc);
 
-        assert(IS_TENTATIVELY_UNREACHABLE(op));
+        PyObject_ASSERT(op, IS_TENTATIVELY_UNREACHABLE(op));
+
         next = gc->gc.gc_next;
 
         if (has_finalizer(op)) {
@@ -570,7 +643,7 @@ handle_weakrefs(PyGC_Head *unreachable,
         PyWeakReference **wrlist;
 
         op = FROM_GC(gc);
-        assert(IS_TENTATIVELY_UNREACHABLE(op));
+        PyObject_ASSERT(op, IS_TENTATIVELY_UNREACHABLE(op));
         next = gc->gc.gc_next;
 
         if (! PyType_SUPPORTS_WEAKREFS(Py_TYPE(op)))
@@ -591,9 +664,9 @@ handle_weakrefs(PyGC_Head *unreachable,
              * the callback pointer intact.  Obscure:  it also
              * changes *wrlist.
              */
-            assert(wr->wr_object == op);
+            PyObject_ASSERT(wr->wr_object, wr->wr_object == op);
             _PyWeakref_ClearRef(wr);
-            assert(wr->wr_object == Py_None);
+            PyObject_ASSERT(wr->wr_object, wr->wr_object == Py_None);
             if (wr->wr_callback == NULL)
                 continue;                       /* no callback */
 
@@ -627,7 +700,7 @@ handle_weakrefs(PyGC_Head *unreachable,
      */
             if (IS_TENTATIVELY_UNREACHABLE(wr))
                 continue;
-            assert(IS_REACHABLE(wr));
+            PyObject_ASSERT(op, IS_REACHABLE(wr));
 
             /* Create a new reference so that wr can't go away
              * before we can process it again.
@@ -636,7 +709,8 @@ handle_weakrefs(PyGC_Head *unreachable,
 
             /* Move wr to wrcb_to_call, for the next pass. */
             wrasgc = AS_GC(wr);
-            assert(wrasgc != next); /* wrasgc is reachable, but
+            PyObject_ASSERT(op, wrasgc != next);
+                                    /* wrasgc is reachable, but
                                        next isn't, so they can't
                                        be the same */
             gc_list_move(wrasgc, &wrcb_to_call);
@@ -652,11 +726,11 @@ handle_weakrefs(PyGC_Head *unreachable,
 
         gc = wrcb_to_call.gc.gc_next;
         op = FROM_GC(gc);
-        assert(IS_REACHABLE(op));
-        assert(PyWeakref_Check(op));
+        PyObject_ASSERT(op, IS_REACHABLE(op));
+        PyObject_ASSERT(op, PyWeakref_Check(op));
         wr = (PyWeakReference *)op;
         callback = wr->wr_callback;
-        assert(callback != NULL);
+        PyObject_ASSERT(op, callback != NULL);
 
         /* copy-paste of weakrefobject.c's handle_callback() */
         temp = PyObject_CallFunctionObjArgs(callback, wr, NULL);
@@ -759,7 +833,7 @@ delete_garbage(PyGC_Head *collectable, P
         PyGC_Head *gc = collectable->gc.gc_next;
         PyObject *op = FROM_GC(gc);
 
-        assert(IS_TENTATIVELY_UNREACHABLE(op));
+        PyObject_ASSERT(op, IS_TENTATIVELY_UNREACHABLE(op));
         if (debug & DEBUG_SAVEALL) {
             PyList_Append(garbage, op);
         }
Commit	Line	Data
48d9a6a0 MT	1	diff -up Python-2.7.3/Lib/test/test_gc.py.gc-assertions Python-2.7.3/Lib/test/test_gc.py
	2	--- Python-2.7.3/Lib/test/test_gc.py.gc-assertions 2013-02-20 16:28:20.890536607 -0500
	3	+++ Python-2.7.3/Lib/test/test_gc.py 2013-02-20 16:39:52.720489297 -0500
	4	@@ -1,6 +1,7 @@
	5	import unittest
4034c523 SS	6	-from test.test_support import verbose, run_unittest, start_threads
4034c523 SS	7	+from test.test_support import verbose, run_unittest, start_threads, import_module
48d9a6a0 MT	8	import sys
	9	+import sysconfig
	10	import time
	11	import gc
	12	import weakref
	13	@@ -32,6 +33,8 @@ class GC_Detector(object):
	14	self.wr = weakref.ref(C1055820(666), it_happened)
	15
	16
	17	+BUILT_WITH_NDEBUG = ('-DNDEBUG' in sysconfig.get_config_vars()['PY_CFLAGS'])
	18	+
	19	### Tests
	20	###############################################################################
	21
	22	@@ -476,6 +479,49 @@ class GCTests(unittest.TestCase):
	23	# would be damaged, with an empty __dict__.
	24	self.assertEqual(x, None)
	25
	26	+ @unittest.skipIf(BUILT_WITH_NDEBUG,
	27	+ 'built with -NDEBUG')
	28	+ def test_refcount_errors(self):
	29	+ # Verify the "handling" of objects with broken refcounts
	30	+
	31	+ import_module("ctypes") #skip if not supported
	32	+
	33	+ import subprocess
	34	+ code = '''if 1:
	35	+ a = []
	36	+ b = [a]
	37	+
	38	+ # Simulate the refcount of "a" being too low (compared to the
	39	+ # references held on it by live data), but keeping it above zero
	40	+ # (to avoid deallocating it):
	41	+ import ctypes
	42	+ ctypes.pythonapi.Py_DecRef(ctypes.py_object(a))
	43	+
	44	+ # The garbage collector should now have a fatal error when it reaches
	45	+ # the broken object:
	46	+ import gc
	47	+ gc.collect()
	48	+ '''
	49	+ p = subprocess.Popen([sys.executable, "-c", code],
	50	+ stdout=subprocess.PIPE,
	51	+ stderr=subprocess.PIPE)
	52	+ stdout, stderr = p.communicate()
	53	+ p.stdout.close()
	54	+ p.stderr.close()
	55	+ # Verify that stderr has a useful error message:
	56	+ self.assertRegexpMatches(stderr,
	57	+ b'Modules/gcmodule.c:[0-9]+: visit_decref: Assertion "gc->gc.gc_refs != 0" failed.')
	58	+ self.assertRegexpMatches(stderr,
	59	+ b'refcount was too small')
	60	+ self.assertRegexpMatches(stderr,
	61	+ b'object : \[\]')
	62	+ self.assertRegexpMatches(stderr,
	63	+ b'type : list')
	64	+ self.assertRegexpMatches(stderr,
	65	+ b'refcount: 1')
	66	+ self.assertRegexpMatches(stderr,
	67	+ b'address : 0x[0-9a-f]+')
	68	+
	69	class GCTogglingTests(unittest.TestCase):
	70	def setUp(self):
	71	gc.enable()
72	diff -up Python-2.7.3/Modules/gcmodule.c.gc-assertions Python-2.7.3/Modules/gcmodule.c
73	--- Python-2.7.3/Modules/gcmodule.c.gc-assertions 2012-04-09 19:07:34.000000000 -0400
74	+++ Python-2.7.3/Modules/gcmodule.c 2013-02-20 16:28:21.029536600 -0500
75	@@ -21,6 +21,73 @@
76	#include "Python.h"
77	#include "frameobject.h" /* for PyFrame_ClearFreeList */
78
79	+/*
80	+ Define a pair of assertion macros.
81	+
82	+ These work like the regular C assert(), in that they will abort the
83	+ process with a message on stderr if the given condition fails to hold,
84	+ but compile away to nothing if NDEBUG is defined.
85	+
86	+ However, before aborting, Python will also try to call _PyObject_Dump() on
87	+ the given object. This may be of use when investigating bugs in which a
88	+ particular object is corrupt (e.g. buggy a tp_visit method in an extension
89	+ module breaking the garbage collector), to help locate the broken objects.
90	+
91	+ The WITH_MSG variant allows you to supply an additional message that Python
92	+ will attempt to print to stderr, after the object dump.
93	+*/
94	+#ifdef NDEBUG
95	+/* No debugging: compile away the assertions: */
96	+#define PyObject_ASSERT_WITH_MSG(obj, expr, msg) ((void)0)
97	+#else
98	+/* With debugging: generate checks: */
99	+#define PyObject_ASSERT_WITH_MSG(obj, expr, msg) \
100	+ ((expr) \
101	+ ? (void)(0) \
102	+ : _PyObject_AssertFailed((obj), \
103	+ (msg), \
104	+ (__STRING(expr)), \
105	+ (__FILE__), \
106	+ (__LINE__), \
107	+ (__PRETTY_FUNCTION__)))
108	+#endif
109	+
110	+#define PyObject_ASSERT(obj, expr) \
111	+ PyObject_ASSERT_WITH_MSG(obj, expr, NULL)
112	+
113	+static void _PyObject_AssertFailed(PyObject , const char ,
114	+ const char , const char , int,
115	+ const char *);
116	+
117	+static void
118	+_PyObject_AssertFailed(PyObject obj, const char msg, const char *expr,
119	+ const char file, int line, const char function)
120	+{
121	+ fprintf(stderr,
122	+ "%s:%d: %s: Assertion \"%s\" failed.\n",
123	+ file, line, function, expr);
124	+ if (msg) {
125	+ fprintf(stderr, "%s\n", msg);
126	+ }
127	+
128	+ fflush(stderr);
129	+
130	+ if (obj) {
131	+ /* This might succeed or fail, but we're about to abort, so at least
132	+ try to provide any extra info we can: */
133	+ _PyObject_Dump(obj);
134	+ }
135	+ else {
136	+ fprintf(stderr, "NULL object\n");
137	+ }
138	+
139	+ fflush(stdout);
140	+ fflush(stderr);
141	+
142	+ /* Terminate the process: */
143	+ abort();
144	+}
145	+
146	/* Get an object's GC head */
147	#define AS_GC(o) ((PyGC_Head *)(o)-1)
148
149	@@ -288,7 +355,8 @@ update_refs(PyGC_Head *containers)
150	{
151	PyGC_Head *gc = containers->gc.gc_next;
152	for (; gc != containers; gc = gc->gc.gc_next) {
153	- assert(gc->gc.gc_refs == GC_REACHABLE);
154	+ PyObject_ASSERT(FROM_GC(gc),
155	+ gc->gc.gc_refs == GC_REACHABLE);
156	gc->gc.gc_refs = Py_REFCNT(FROM_GC(gc));
157	/* Python's cyclic gc should never see an incoming refcount
158	* of 0: if something decref'ed to 0, it should have been
159	@@ -308,7 +376,8 @@ update_refs(PyGC_Head *containers)
160	* so serious that maybe this should be a release-build
161	* check instead of an assert?
162	*/
163	- assert(gc->gc.gc_refs != 0);
164	+ PyObject_ASSERT(FROM_GC(gc),
165	+ gc->gc.gc_refs != 0);
166	}
167	}
168
169	@@ -323,7 +392,9 @@ visit_decref(PyObject op, void data)
170	* generation being collected, which can be recognized
171	* because only they have positive gc_refs.
172	*/
173	- assert(gc->gc.gc_refs != 0); /* else refcount was too small */
174	+ PyObject_ASSERT_WITH_MSG(FROM_GC(gc),
175	+ gc->gc.gc_refs != 0,
176	+ "refcount was too small");
177	if (gc->gc.gc_refs > 0)
178	gc->gc.gc_refs--;
179	}
180	@@ -383,9 +454,10 @@ visit_reachable(PyObject *op, PyGC_Head
181	* If gc_refs == GC_UNTRACKED, it must be ignored.
182	*/
183	else {
184	- assert(gc_refs > 0
185	- \|\| gc_refs == GC_REACHABLE
186	- \|\| gc_refs == GC_UNTRACKED);
187	+ PyObject_ASSERT(FROM_GC(gc),
188	+ gc_refs > 0
189	+ \|\| gc_refs == GC_REACHABLE
190	+ \|\| gc_refs == GC_UNTRACKED);
191	}
192	}
193	return 0;
194	@@ -427,7 +499,7 @@ move_unreachable(PyGC_Head *young, PyGC_
195	*/
196	PyObject *op = FROM_GC(gc);
197	traverseproc traverse = Py_TYPE(op)->tp_traverse;
198	- assert(gc->gc.gc_refs > 0);
199	+ PyObject_ASSERT(op, gc->gc.gc_refs > 0);
200	gc->gc.gc_refs = GC_REACHABLE;
201	(void) traverse(op,
202	(visitproc)visit_reachable,
203	@@ -494,7 +566,8 @@ move_finalizers(PyGC_Head *unreachable,
204	for (gc = unreachable->gc.gc_next; gc != unreachable; gc = next) {
205	PyObject *op = FROM_GC(gc);
206
207	- assert(IS_TENTATIVELY_UNREACHABLE(op));
208	+ PyObject_ASSERT(op, IS_TENTATIVELY_UNREACHABLE(op));
209	+
210	next = gc->gc.gc_next;
211
212	if (has_finalizer(op)) {
213	@@ -570,7 +643,7 @@ handle_weakrefs(PyGC_Head *unreachable,
214	PyWeakReference **wrlist;
215
216	op = FROM_GC(gc);
217	- assert(IS_TENTATIVELY_UNREACHABLE(op));
218	+ PyObject_ASSERT(op, IS_TENTATIVELY_UNREACHABLE(op));
219	next = gc->gc.gc_next;
220
221	if (! PyType_SUPPORTS_WEAKREFS(Py_TYPE(op)))
222	@@ -591,9 +664,9 @@ handle_weakrefs(PyGC_Head *unreachable,
223	* the callback pointer intact. Obscure: it also
224	* changes *wrlist.
225	*/
226	- assert(wr->wr_object == op);
227	+ PyObject_ASSERT(wr->wr_object, wr->wr_object == op);
228	_PyWeakref_ClearRef(wr);
229	- assert(wr->wr_object == Py_None);
230	+ PyObject_ASSERT(wr->wr_object, wr->wr_object == Py_None);
231	if (wr->wr_callback == NULL)
232	continue; /* no callback */
233
234	@@ -627,7 +700,7 @@ handle_weakrefs(PyGC_Head *unreachable,
235	*/
236	if (IS_TENTATIVELY_UNREACHABLE(wr))
237	continue;
238	- assert(IS_REACHABLE(wr));
239	+ PyObject_ASSERT(op, IS_REACHABLE(wr));
240
241	/* Create a new reference so that wr can't go away
242	* before we can process it again.
243	@@ -636,7 +709,8 @@ handle_weakrefs(PyGC_Head *unreachable,
244
245	/* Move wr to wrcb_to_call, for the next pass. */
246	wrasgc = AS_GC(wr);
247	- assert(wrasgc != next); /* wrasgc is reachable, but
248	+ PyObject_ASSERT(op, wrasgc != next);
249	+ /* wrasgc is reachable, but
250	next isn't, so they can't
251	be the same */
252	gc_list_move(wrasgc, &wrcb_to_call);
253	@@ -652,11 +726,11 @@ handle_weakrefs(PyGC_Head *unreachable,
254
255	gc = wrcb_to_call.gc.gc_next;
256	op = FROM_GC(gc);
257	- assert(IS_REACHABLE(op));
258	- assert(PyWeakref_Check(op));
259	+ PyObject_ASSERT(op, IS_REACHABLE(op));
260	+ PyObject_ASSERT(op, PyWeakref_Check(op));
261	wr = (PyWeakReference *)op;
262	callback = wr->wr_callback;
263	- assert(callback != NULL);
264	+ PyObject_ASSERT(op, callback != NULL);
265
266	/* copy-paste of weakrefobject.c's handle_callback() */
267	temp = PyObject_CallFunctionObjArgs(callback, wr, NULL);
268	@@ -759,7 +833,7 @@ delete_garbage(PyGC_Head *collectable, P
269	PyGC_Head *gc = collectable->gc.gc_next;
270	PyObject *op = FROM_GC(gc);
271
272	- assert(IS_TENTATIVELY_UNREACHABLE(op));
273	+ PyObject_ASSERT(op, IS_TENTATIVELY_UNREACHABLE(op));
274	if (debug & DEBUG_SAVEALL) {
275	PyList_Append(garbage, op);
276	}