Regression: Crash when running modal operator in load_post handler #107759

New Issue

Ryan Guy · 2023-05-08T21:39:04+02:00

Ryan Guy commented

2023-05-08 21:39:04 +02:00

System Information
Operating system: Windows-10-10.0.22621-SP0 64 Bits
Graphics card: NVIDIA GeForce RTX 4090/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 528.49

Blender Version
Broken: version: 3.6.0 Alpha, branch: main, commit date: 2023-05-08 10:47, hash: f6b492c43dbd
Worked: 3.5.0, branch: blender-v3.5-release, commit date: 2023-03-29 02:56, hash: 1be25cfff18b

Caused by 46be42f6b1

Short description of error

I have an addon that starts running a modal timer operator within the load_post handler. In Blender 3.6, this results in a crash. This has worked without crash in previous versions of Blender 3.5 or earlier.

Here is a minimal addon script that uses the operator_modal_timer.py template operator:

bl_info = {
    "name": "Modal Timer Add-on",
    "blender": (2, 80, 0),
    "category": "Object",
}

import bpy

class ModalTimerOperator(bpy.types.Operator):
    bl_idname = "wm.modal_timer_operator"
    bl_label = "Modal Timer Operator"

    _timer = None

    def modal(self, context, event):
        if event.type == 'TIMER':
            print("Running Modal...")
        return {'PASS_THROUGH'}

    def execute(self, context):
        wm = context.window_manager
        self._timer = wm.event_timer_add(0.5, window=context.window)
        wm.modal_handler_add(self)
        return {'RUNNING_MODAL'}

    def cancel(self, context):
        wm = context.window_manager
        wm.event_timer_remove(self._timer)

@bpy.app.handlers.persistent
def load_post_func(scene):
    print("Load Post")
    bpy.ops.wm.modal_timer_operator()
    
def register():
    bpy.utils.register_class(ModalTimerOperator)
    bpy.app.handlers.load_post.append(load_post_func)

def unregister():
    bpy.utils.unregister_class(ModalTimerOperator)
    bpy.app.handlers.load_post.remove(load_post_func)

This is the EXCEPTION_ACCESS_VIOLATION message:

Error   : EXCEPTION_ACCESS_VIOLATION
Address : 0x00007FF715339725
Module  : blender.exe
Thread  : 000012dc
Writing: C:\Users\ryanl\AppData\Local\Temp\blender.crash.txt

Crash log: blender.crash.txt

If the modal operator is run using bpy.ops.wm.modal_timer_operator('INVOKE_DEFAULT'), a crash does not occur, but the following error message is displayed which prevents the operator from running:

Traceback (most recent call last):
  File "C:\Users\ryanl\AppData\Roaming\Blender Foundation\Blender\3.6\scripts\addons\modal_timer_addon.py", line 33, in load_post_func
    bpy.ops.wm.modal_timer_operator('INVOKE_DEFAULT')
  File "C:\Program Files\blender\3.6.0-alpha+main.f6b492c43dbd-windows.amd64-release\3.6\scripts\modules\bpy\ops.py", line 111, in __call__
    ret = _op_call(self.idname_py(), C_dict, kw, C_exec, C_undo)
RuntimeError: Operator bpy.ops.wm.modal_timer_operator.poll() Missing 'window' in context

Exact steps for others to reproduce the error

Open Blender
Install and enable the modal_timer_addon.py` addon
Open a Blend file to run the load_post handler (File > New > General)

Result: Blender crash

**System Information** Operating system: Windows-10-10.0.22621-SP0 64 Bits Graphics card: NVIDIA GeForce RTX 4090/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 528.49 **Blender Version** Broken: version: 3.6.0 Alpha, branch: main, commit date: 2023-05-08 10:47, hash: `f6b492c43dbd` Worked: 3.5.0, branch: blender-v3.5-release, commit date: 2023-03-29 02:56, hash: `1be25cfff18b` Caused by 46be42f6b16314f59a37ebb430d77d12e7a88461 **Short description of error** I have an addon that starts running a modal timer operator within the ```load_post``` handler. In Blender 3.6, this results in a crash. This has worked without crash in previous versions of Blender 3.5 or earlier. Here is a minimal addon script that uses the ```operator_modal_timer.py``` template operator: ```python bl_info = { "name": "Modal Timer Add-on", "blender": (2, 80, 0), "category": "Object", } import bpy class ModalTimerOperator(bpy.types.Operator): bl_idname = "wm.modal_timer_operator" bl_label = "Modal Timer Operator" _timer = None def modal(self, context, event): if event.type == 'TIMER': print("Running Modal...") return {'PASS_THROUGH'} def execute(self, context): wm = context.window_manager self._timer = wm.event_timer_add(0.5, window=context.window) wm.modal_handler_add(self) return {'RUNNING_MODAL'} def cancel(self, context): wm = context.window_manager wm.event_timer_remove(self._timer) @bpy.app.handlers.persistent def load_post_func(scene): print("Load Post") bpy.ops.wm.modal_timer_operator() def register(): bpy.utils.register_class(ModalTimerOperator) bpy.app.handlers.load_post.append(load_post_func) def unregister(): bpy.utils.unregister_class(ModalTimerOperator) bpy.app.handlers.load_post.remove(load_post_func) ``` This is the EXCEPTION_ACCESS_VIOLATION message: ``` Error : EXCEPTION_ACCESS_VIOLATION Address : 0x00007FF715339725 Module : blender.exe Thread : 000012dc Writing: C:\Users\ryanl\AppData\Local\Temp\blender.crash.txt ``` Crash log: [blender.crash.txt](/attachments/2a08cf98-868c-431a-9cee-4d178d9f9c02) If the modal operator is run using ```bpy.ops.wm.modal_timer_operator('INVOKE_DEFAULT')```, a crash does not occur, but the following error message is displayed which prevents the operator from running: ``` Traceback (most recent call last): File "C:\Users\ryanl\AppData\Roaming\Blender Foundation\Blender\3.6\scripts\addons\modal_timer_addon.py", line 33, in load_post_func bpy.ops.wm.modal_timer_operator('INVOKE_DEFAULT') File "C:\Program Files\blender\3.6.0-alpha+main.f6b492c43dbd-windows.amd64-release\3.6\scripts\modules\bpy\ops.py", line 111, in __call__ ret = _op_call(self.idname_py(), C_dict, kw, C_exec, C_undo) RuntimeError: Operator bpy.ops.wm.modal_timer_operator.poll() Missing 'window' in context ``` **Exact steps for others to reproduce the error** 1. Open Blender 2. Install and enable the [modal_timer_addon.py](/attachments/7159bf7c-397e-4147-892b-ded1739785bd)` addon 3. Open a Blend file to run the ```load_post``` handler (File > New > General) Result: Blender crash

blender.crash.txt

47 KiB

modal_timer_addon.py

1.1 KiB

Ryan Guy added the

labels 2023-05-08 21:39:04 +02:00

Iliya Katushenock changed title from ~~EXCEPTION_ACCESS_VIOLATION crash when running modal operator in load_post handler in Blender 3.6~~ to Regression: Crash when running modal operator in load_post handler

2023-05-08 21:39:56 +02:00

Iliya Katushenock added the

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Regression: Crash when running modal operator in load_post handler #107759