Segmentation fault when appending None to Collection types

[reinecke]

Bug Report

Incorrect Functionality and General Questions

When None is passed to the append method on a collection, the python interpreter exits with a Segmentation Fault. I first encountered this in Track, but traced the behavior up the object hierarchy to Collection and verified in Stack as well.

Track

% python
Python 3.11.5 (main, Aug 24 2023, 15:09:45) [Clang 14.0.3 (clang-1403.0.22.14.1)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import opentimelineio as otio
>>> track = otio.schema.Track()
>>> track.append(None)
zsh: segmentation fault  python

Stack

% python
Python 3.11.5 (main, Aug 24 2023, 15:09:45) [Clang 14.0.3 (clang-1403.0.22.14.1)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import opentimelineio as otio
>>> stack = otio.schema.Stack()
>>> stack.append(None)
zsh: segmentation fault  python

Composition

% python
Python 3.11.5 (main, Aug 24 2023, 15:09:45) [Clang 14.0.3 (clang-1403.0.22.14.1)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import opentimelineio as otio
>>> composition = otio.core.Composition()
>>> composition.append(None)
zsh: segmentation fault  python

SerializableCollection

Interestingly, SerializableCollection behaves differently, but still incorrectly:

>>> import opentimelineio as otio
>>> bin = otio.schema.SerializableCollection()
>>> bin.append(None)
>>> bin
otio.schema.SerializableCollection(name='', children=[None], metadata={})

To Reproduce

1. Operating system: macOS 13.6.1 (22G313) Apple M2
2. Python version: 3.11.5
3. OpenTimelineIO release version or commit hash: b680372
4. Compiler information:
   Apple clang version 15.0.0 (clang-1500.0.40.1)
   Target: arm64-apple-darwin22.6.0
   Thread model: posix
   InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin

Expected Behavior

We should throw a TypeError exception as in the following example:

>>> import opentimelineio as otio
>>> composition = otio.core.Composition()
>>> composition.append("not a Composable")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "<frozen _collections_abc>", line 1078, in append
  File "/Users/ereinecke/Projects/github/OpenTimelineIO/.venv/lib/python3.11/site-packages/OpenTimelineIO-0.16.0.dev1-py3.11-macosx-13-arm64.egg/opentimelineio/core/_core_utils.py", line 303, in insert
    self.__internal_insert(
TypeError: __internal_insert(): incompatible function arguments. The following argument types are supported:
    1. (self: opentimelineio._otio.Composition, index: int, item: opentimelineio._otio.Composable) -> None

Invoked with: otio.core.Composition(name='', children=[], source_range=None, metadata={}), 0, 'not a Composable'

Logs

Full crash log from macOS crash report:

-------------------------------------
Translated Report (Full Report Below)
-------------------------------------

Process:               Python [54268]
Path:                  /opt/homebrew/*/Python.framework/Versions/3.11/Resources/Python.app/Contents/MacOS/Python
Identifier:            org.python.python
Version:               3.11.5 (3.11.5)
Code Type:             ARM-64 (Native)
Parent Process:        zsh [10120]
User ID:               501

Date/Time:             2023-11-16 11:48:25.7105 -0800
OS Version:            macOS 13.6.1 (22G313)
Report Version:        12
Anonymous UUID:        D48FAC32-27A3-28E8-3F9F-CC4F0DBF675B

Sleep/Wake UUID:       ACB5B591-B66F-4C7E-9739-0D1782460EA3

Time Awake Since Boot: 510000 seconds
Time Since Wake:       6869 seconds

System Integrity Protection: enabled

Crashed Thread:        0  Dispatch queue: com.apple.main-thread

Exception Type:        EXC_BAD_ACCESS (SIGSEGV)
Exception Codes:       KERN_INVALID_ADDRESS at 0x00000000000000d0
Exception Codes:       0x0000000000000001, 0x00000000000000d0

Termination Reason:    Namespace SIGNAL, Code 11 Segmentation fault: 11
Terminating Process:   exc handler [54268]

VM Region Info: 0xd0 is not in any region.  Bytes before following region: 105553518919472
      REGION TYPE                    START - END         [ VSIZE] PRT/MAX SHRMOD  REGION DETAIL
      UNUSED SPACE AT START
--->  
      MALLOC_NANO (reserved)   600018000000-600020000000 [128.0M] rw-/rwx SM=NUL  ...(unallocated)

Thread 0 Crashed::  Dispatch queue: com.apple.main-thread
0   _otio.cpython-311-darwin.so   	       0x102e3f878 0x102dac000 + 604280
1   _otio.cpython-311-darwin.so   	       0x102e2fe50 0x102dac000 + 540240
2   _otio.cpython-311-darwin.so   	       0x102db8184 0x102dac000 + 49540
3   Python                        	       0x10270f92c cfunction_call + 60
4   Python                        	       0x1026c7e34 _PyObject_MakeTpCall + 128
5   Python                        	       0x1027a0078 _PyEval_EvalFrameDefault + 40660
6   Python                        	       0x102795660 PyEval_EvalCode + 168
7   Python                        	       0x1027e80ec run_eval_code_obj + 84
8   Python                        	       0x1027e8050 run_mod + 112
9   Python                        	       0x1027e8384 PyRun_InteractiveOneObjectEx + 548
10  Python                        	       0x1027e7748 _PyRun_InteractiveLoopObject + 288
11  Python                        	       0x1027e71e8 _PyRun_AnyFileObject + 76
12  Python                        	       0x1027ea108 PyRun_AnyFileExFlags + 84
13  Python                        	       0x102802bdc pymain_run_stdin + 160
14  Python                        	       0x102802228 Py_RunMain + 348
15  Python                        	       0x1028034c4 Py_BytesMain + 40
16  dyld                          	       0x18a27ff28 start + 2236


Thread 0 crashed with ARM Thread State (64-bit):
    x0: 0x0000000137e04400   x1: 0x0000000000000000   x2: 0x0000000000000000   x3: 0x000000016dc965f0
    x4: 0x000000016dc96298   x5: 0x0000000000000002   x6: 0x0000000000000027   x7: 0x0000000000000005
    x8: 0x0000000000000001   x9: 0x0000000000000087  x10: 0x0000000103197910  x11: 0x0000000000000000
   x12: 0x00000001029a3ee0  x13: 0x00000001029a3ee0  x14: 0x0000000102941780  x15: 0x000000010287e500
   x16: 0x000000018a606940  x17: 0x000000005f5f3230  x18: 0x0000000000000000  x19: 0x0000000000000001
   x20: 0x000000016dc967b0  x21: 0x000000016dc965d8  x22: 0x0000000000000001  x23: 0x0000600002660680
   x24: 0x0000000000000003  x25: 0x00006000008715d8  x26: 0x0000000000000001  x27: 0x0000000102a255d8
   x28: 0x000000010319e800   fp: 0x000000016dc965a0   lr: 0x0000000102e2fe50
    sp: 0x000000016dc96560   pc: 0x0000000102e3f878 cpsr: 0x60001000
   far: 0x00000000000000d0  esr: 0x92000006 (Data Abort) byte read Translation fault

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       0x18a27a000 -        0x18a308587 dyld (*) <49204446-242b-3d1e-9704-32f8ac99723e> /usr/lib/dyld
               0x0 - 0xffffffffffffffff ??? (*) <00000000-0000-0000-0000-000000000000> ???

External Modification Summary:
  Calls made by other processes targeting this process:
    task_for_pid: 0
    thread_create: 0
    thread_set_state: 0
  Calls made by this process:
    task_for_pid: 0
    thread_create: 0
    thread_set_state: 0
  Calls made by all processes on this machine:
    task_for_pid: 0
    thread_create: 0
    thread_set_state: 0

VM Region Summary:
ReadOnly portion of Libraries: Total=922.8M resident=0K(0%) swapped_out_or_unallocated=922.8M(100%)
Writable regions: Total=1.1G written=0K(0%) resident=0K(0%) swapped_out=0K(0%) unallocated=1.1G(100%)

                                VIRTUAL   REGION 
REGION TYPE                        SIZE    COUNT (non-coalesced) 
===========                     =======  ======= 
Kernel Alloc Once                   32K        1 
MALLOC                           215.2M       26 
MALLOC guard page                   96K        5 
MALLOC_MEDIUM (reserved)         480.0M        4         reserved VM address space (unallocated)
MALLOC_NANO (reserved)           384.0M        1         reserved VM address space (unallocated)
STACK GUARD                         16K        1 
Stack                             16.0M        1 
VM_ALLOCATE                       8208K        9 
__AUTH                             309K       60 
__AUTH_CONST                      3716K      144 
__DATA                            3326K      166 
__DATA_CONST                      5123K      173 
__DATA_DIRTY                       361K       58 
__LINKEDIT                       804.4M       29 
__OBJC_RO                         66.4M        1 
__OBJC_RW                         2012K        1 
__TEXT                           118.4M      180 
dyld private memory                272K        2 
shared memory                       32K        2 
===========                     =======  ======= 
TOTAL                              2.1G      864 
TOTAL, minus reserved VM space     1.2G      864 



-----------
Full Report
-----------

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[JeanChristopheMorinPerso]

Composition and SerializableCollection are handled slightly differently:

OpenTimelineIO/src/py-opentimelineio/opentimelineio/core/_core_utils.py

Lines 359 to 360 in 17e9297

	_add_mutable_sequence_methods(_otio.Composition, side_effecting_insertions=True)
	_add_mutable_sequence_methods(_otio.SerializableCollection)

Here is the backtrace with OTIO built in debug mode:

Thread 0 Crashed::  Dispatch queue: com.apple.main-thread
0   _otio.cpython-311-darwin.so   	       0x1062db050 opentimelineio::v1_0::Composable::parent() const + 12
1   _otio.cpython-311-darwin.so   	       0x10634b698 opentimelineio::v1_0::Composition::insert_child(int, opentimelineio::v1_0::Composable*, opentimelineio::v1_0::ErrorStatus*) + 44
2   _otio.cpython-311-darwin.so   	       0x10630b794 define_items_and_compositions(pybind11::module_)::$_67::operator()(opentimelineio::v1_0::Composition*, int, opentimelineio::v1_0::Composable*) const + 140
3   _otio.cpython-311-darwin.so   	       0x10630b6fc void pybind11::detail::argument_loader<opentimelineio::v1_0::Composition*, int, opentimelineio::v1_0::Composable*>::call_impl<void, define_items_and_compositions(pybind11::module_)::$_67&, 0ul, 1ul, 2ul, pybind11::detail::void_type>(define_items_and_compositions(pybind11::module_)::$_67&, std::__1::integer_sequence<unsigned long, 0ul, 1ul, 2ul>, pybind11::detail::void_type&&) && + 112
4   _otio.cpython-311-darwin.so   	       0x10630b680 std::__1::enable_if<std::is_void<void>::value, pybind11::detail::void_type>::type pybind11::detail::argument_loader<opentimelineio::v1_0::Composition*, int, opentimelineio::v1_0::Composable*>::call<void, pybind11::detail::void_type, define_items_and_compositions(pybind11::module_)::$_67&>(define_items_and_compositions(pybind11::module_)::$_67&) && + 36
5   _otio.cpython-311-darwin.so   	       0x10630b618 void pybind11::cpp_function::initialize<define_items_and_compositions(pybind11::module_)::$_67, void, opentimelineio::v1_0::Composition*, int, opentimelineio::v1_0::Composable*, pybind11::name, pybind11::is_method, pybind11::sibling, pybind11::arg, pybind11::arg>(define_items_and_compositions(pybind11::module_)::$_67&&, void (*)(opentimelineio::v1_0::Composition*, int, opentimelineio::v1_0::Composable*), pybind11::name const&, pybind11::is_method const&, pybind11::sibling const&, pybind11::arg const&, pybind11::arg const&)::'lambda'(pybind11::detail::function_call&)::operator()(pybind11::detail::function_call&) const + 132
6   _otio.cpython-311-darwin.so   	       0x10630b578 void pybind11::cpp_function::initialize<define_items_and_compositions(pybind11::module_)::$_67, void, opentimelineio::v1_0::Composition*, int, opentimelineio::v1_0::Composable*, pybind11::name, pybind11::is_method, pybind11::sibling, pybind11::arg, pybind11::arg>(define_items_and_compositions(pybind11::module_)::$_67&&, void (*)(opentimelineio::v1_0::Composition*, int, opentimelineio::v1_0::Composable*), pybind11::name const&, pybind11::is_method const&, pybind11::sibling const&, pybind11::arg const&, pybind11::arg const&)::'lambda'(pybind11::detail::function_call&)::__invoke(pybind11::detail::function_call&) + 28
7   _otio.cpython-311-darwin.so   	       0x1061b8354 pybind11::cpp_function::dispatcher(_object*, _object*, _object*) + 4020
8   Python                        	       0x1048fef4c cfunction_call + 60
9   Python                        	       0x1048b6cd0 _PyObject_MakeTpCall + 128
10  Python                        	       0x10498fe34 _PyEval_EvalFrameDefault + 40596
11  Python                        	       0x104985444 PyEval_EvalCode + 168
12  Python                        	       0x1049daa18 run_eval_code_obj + 84
13  Python                        	       0x1049da97c run_mod + 112
14  Python                        	       0x1049dcdbc PyRun_StringFlags + 112
15  Python                        	       0x1049dcd04 PyRun_SimpleStringFlags + 64
16  Python                        	       0x1049f54e0 pymain_run_command + 144
17  Python                        	       0x1049f4fb4 Py_RunMain + 228
18  Python                        	       0x1049f62c8 Py_BytesMain + 40
19  dyld                          	       0x18af1bf28 start + 2236

[JeanChristopheMorinPerso]

A fix could simply be something like

diff --git a/src/py-opentimelineio/opentimelineio-bindings/otio_serializableObjects.cpp b/src/py-opentimelineio/opentimelineio-bindings/otio_serializableObjects.cpp
index c52ab4c..37c5957 100644
--- a/src/py-opentimelineio/opentimelineio-bindings/otio_serializableObjects.cpp
+++ b/src/py-opentimelineio/opentimelineio-bindings/otio_serializableObjects.cpp
@@ -521,9 +521,9 @@ Should be subclassed (for example by :class:`.Track` and :class:`.Stack`), not u
                 index = adjusted_vector_index(index, c->children());
                 c->remove_child(index, ErrorStatusHandler());
             }, "index"_a)
-        .def("__internal_insert", [](Composition* c, int index, Composable* composable) {
+        .def("__internal_insert", [](Composition* c, int index, Composable &composable) {
                 index = adjusted_vector_index(index, c->children());
-                c->insert_child(index, composable, ErrorStatusHandler());
+                c->insert_child(index, &composable, ErrorStatusHandler());
             }, "index"_a, "item"_a)
         .def("__contains__", &Composition::has_child, "composable"_a)
         .def("__len__", [](Composition* c) {

which gives us what you want:

(.venv) jcmorin$ python -c 'import opentimelineio as otio; track = otio.schema.Track(); track.append(None)'
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "<frozen _collections_abc>", line 1078, in append
  File "/private/tmp/asd/.venv/lib/python3.11/site-packages/opentimelineio/core/_core_utils.py", line 359, in insert
    self.__internal_insert(
TypeError: __internal_insert(): incompatible function arguments. The following argument types are supported:
    1. (self: opentimelineio._otio.Composition, index: int, item: opentimelineio._otio.Composable) -> None

Invoked with: otio.schema.Track(name='', children=[], source_range=None, metadata={}), 0, None

[JeanChristopheMorinPerso]

I personally always wondered why OTIO uses pointer parameters for these things instead of reference parameters in the python bindings.