Initial import (#1219411)

1 files changed, 325 insertions, 0 deletions

diff --git a/00170-gc-assertions.patch b/00170-gc-assertions.patch
new file mode 100644
index 0000000..1144cc2
--- /dev/null
+++ b/00170-gc-assertions.patch
@@ -0,0 +1,325 @@
+Index: Include/object.h
+===================================================================
+--- Include/object.h	(revision 87911)
++++ Include/object.h	(working copy)
+@@ -914,6 +914,49 @@
+ _PyObject_DebugTypeStats(FILE *out);
+ #endif /* ifndef Py_LIMITED_API */
+ 
++/* 
++   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)
++
++/* 
++   Declare and define the entrypoint even when NDEBUG is defined, to avoid
++   causing compiler/linker errors when building extensions without NDEBUG
++   against a Python built with NDEBUG defined
++*/
++PyAPI_FUNC(void) _PyObject_AssertFailed(PyObject *,  const char *,
++                                        const char *, const char *, int,
++                                        const char *);
++
+ #ifdef __cplusplus
+ }
+ #endif
+Index: Objects/object.c
+===================================================================
+--- Objects/object.c	(revision 87911)
++++ Objects/object.c	(working copy)
+@@ -1899,6 +1899,35 @@
+     }
+ }
+ 
++PyAPI_FUNC(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();
++}
++
+ #ifndef Py_TRACE_REFS
+ /* For Py_LIMITED_API, we need an out-of-line version of _Py_Dealloc.
+    Define this here, so we can undefine the macro. */
+Index: Lib/test/test_gc.py
+===================================================================
+--- Lib/test/test_gc.py	(revision 87911)
++++ Lib/test/test_gc.py	(working copy)
+@@ -1,6 +1,6 @@
+ import unittest
+ from test.support import (verbose, refcount_test, run_unittest,
+-                            strip_python_stderr, cpython_only)
++                            strip_python_stderr, cpython_only, import_module)
+ from test.script_helper import assert_python_ok, make_script, temp_dir
+
+ import sys
+@@ -512,6 +512,48 @@
+         self.assertEqual(len(gc.garbage), 0)
+ 
+ 
++    def test_refcount_errors(self):
++        self.preclean()
++        # 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.assertRegex(stderr,
++            b'Modules/gcmodule.c:[0-9]+: visit_decref: Assertion "\(\(gc\)->gc.gc_refs >> \(1\)\) != 0" failed.')
++        self.assertRegex(stderr,
++            b'refcount was too small')
++        self.assertRegex(stderr,
++            b'object  : \[\]')
++        self.assertRegex(stderr,
++            b'type    : list')
++        self.assertRegex(stderr,
++            b'refcount: 1')
++        self.assertRegex(stderr,
++            b'address : 0x[0-9a-f]+')
++
++
+ class GCTogglingTests(unittest.TestCase):
+     def setUp(self):
+         gc.enable()
+diff -up Modules/gcmodule.c.orig2 Modules/gcmodule.c
+--- Modules/gcmodule.c.orig2	2014-12-08 10:54:14.251742911 +0100
++++ Modules/gcmodule.c	2014-12-08 10:52:45.674771917 +0100
+@@ -341,7 +341,8 @@ update_refs(PyGC_Head *containers)
+ {
+     PyGC_Head *gc = containers->gc.gc_next;
+     for (; gc != containers; gc = gc->gc.gc_next) {
+-        assert(_PyGCHead_REFS(gc) == GC_REACHABLE);
++        PyObject_ASSERT(FROM_GC(gc),
++                        _PyGCHead_REFS(gc) == GC_REACHABLE);
+         _PyGCHead_SET_REFS(gc, 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
+@@ -361,7 +362,8 @@ update_refs(PyGC_Head *containers)
+          * so serious that maybe this should be a release-build
+          * check instead of an assert?
+          */
+-        assert(_PyGCHead_REFS(gc) != 0);
++        PyObject_ASSERT(FROM_GC(gc),
++                        _PyGCHead_REFS(gc) != 0);
+     }
+ }
+ 
+@@ -376,7 +378,9 @@ visit_decref(PyObject *op, void *data)
+          * generation being collected, which can be recognized
+          * because only they have positive gc_refs.
+          */
+-        assert(_PyGCHead_REFS(gc) != 0); /* else refcount was too small */
++        PyObject_ASSERT_WITH_MSG(FROM_GC(gc),
++                        _PyGCHead_REFS(gc) != 0,
++                        "refcount was too small"); /* else refcount was too small */
+         if (_PyGCHead_REFS(gc) > 0)
+             _PyGCHead_DECREF(gc);
+     }
+@@ -436,9 +440,10 @@ 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;
+@@ -480,7 +485,7 @@ move_unreachable(PyGC_Head *young, PyGC_
+              */
+             PyObject *op = FROM_GC(gc);
+             traverseproc traverse = Py_TYPE(op)->tp_traverse;
+-            assert(_PyGCHead_REFS(gc) > 0);
++            PyObject_ASSERT(op, _PyGCHead_REFS(gc) > 0);
+             _PyGCHead_SET_REFS(gc, GC_REACHABLE);
+             (void) traverse(op,
+                             (visitproc)visit_reachable,
+@@ -543,7 +548,7 @@ move_legacy_finalizers(PyGC_Head *unreac
+     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_legacy_finalizer(op)) {
+@@ -619,7 +624,7 @@ 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)))
+@@ -640,9 +645,9 @@ 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 */
+ 
+@@ -676,7 +681,7 @@ 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.
+@@ -685,7 +690,8 @@ 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);
+@@ -701,11 +707,11 @@ 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);
+@@ -822,12 +828,14 @@ check_garbage(PyGC_Head *collectable)
+     for (gc = collectable->gc.gc_next; gc != collectable;
+          gc = gc->gc.gc_next) {
+         _PyGCHead_SET_REFS(gc, Py_REFCNT(FROM_GC(gc)));
+-        assert(_PyGCHead_REFS(gc) != 0);
++        PyObject_ASSERT(FROM_GC(gc),
++                        _PyGCHead_REFS(gc) != 0);
+     }
+     subtract_refs(collectable);
+     for (gc = collectable->gc.gc_next; gc != collectable;
+          gc = gc->gc.gc_next) {
+-        assert(_PyGCHead_REFS(gc) >= 0);
++        PyObject_ASSERT(FROM_GC(gc),
++                        _PyGCHead_REFS(gc) >= 0);
+         if (_PyGCHead_REFS(gc) != 0)
+             return -1;
+     }
+diff -up Lib/test/test_gc.py.old Lib/test/test_gc.py
+--- Lib/test/test_gc.py.old	2014-12-10 11:19:33.503982288 +0100
++++ Lib/test/test_gc.py	2014-12-10 11:21:13.220021364 +0100
+@@ -49,6 +49,8 @@ class GC_Detector(object):
+         # gc collects it.
+         self.wr = weakref.ref(C1055820(666), it_happened)
+ 
++BUILD_WITH_NDEBUG = ('-DNDEBUG' in sysconfig.get_config_vars()['PY_CFLAGS'])
++
+ @with_tp_del
+ class Uncollectable(object):
+     """Create a reference cycle with multiple __del__ methods.
+@@ -854,6 +856,8 @@ class GCCallbackTests(unittest.TestCase)
+         self.assertEqual(len(gc.garbage), 0)
+ 
+ 
++    @unittest.skipIf(BUILD_WITH_NDEBUG,
++                     'built with -NDEBUG')
+     def test_refcount_errors(self):
+         self.preclean()
+         # Verify the "handling" of objects with broken refcounts
+diff -up Lib/test/test_gc.py.old Lib/test/test_gc.py
+--- Lib/test/test_gc.py.old	2014-12-10 12:50:58.252121318 +0100
++++ Lib/test/test_gc.py	2014-12-10 12:51:08.594266653 +0100
+@@ -4,6 +4,7 @@ from test.support import (verbose, refco
+ from test.script_helper import assert_python_ok, make_script, temp_dir
+ 
+ import sys
++import sysconfig
+ import time
+ import gc
+ import weakref