Occasionally bpy.app.is_job_running('RENDER') and bpy.app.is_job_running('COMPOSITE') incorrectly return False #114455

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opened 2023-11-03 13:27:35 +01:00 by michael campbell · 27 comments

michael campbell commented 2023-11-03 13:27:35 +01:00

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System Information
Operating system: Windows-10-10.0.19045-SP0 64 Bits
Graphics card: NVIDIA GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 537.58

Blender Version
Broken: version: 4.1.0 Alpha, branch: main, commit date: 2023-11-01 18:56, hash: ab9ce556a124
Worked: (unknown)

Short description of error
I have an addon that sets a few settings back after rendering using:

if bpy.app.version >= (3,3,0):
    if not (bpy.app.is_job_running('RENDER') or bpy.app.is_job_running('COMPOSITE')) :
        bpy.data.scenes['Scene'].cycles.samples = 256
        bpy.data.scenes['Scene'].cycles.adaptive_min_samples = 16
        bpy.data.scenes['Scene'].cycles.adaptive_threshold = 0.01        
        bpy.data.scenes['Scene'].cycles.use_adaptive_sampling = True

Very rarely I get a python error saying, can't write to cycles.samples in this context. I know it's not related to the screen context (what the mouse is over), so I'm guessing something inside of Blender still thinks it's either rendering or compsositing, despite me checking with the second line above.

Once the error happens, it keeps happening after every render until I restart Blender.

Exact steps for others to reproduce the error

It's so intermittent, I don't think it's feasible to try and replicate. I'm hoping it will be obvious to those familiar with Cycles code which bit of C++ code would be responsible.

If not, let me know and I'll create an addon that will repeatedly render until the error happens. I don't think this is the best idea, because sometimes it doesn't happen for months.

**System Information** Operating system: Windows-10-10.0.19045-SP0 64 Bits Graphics card: NVIDIA GeForce GTX 1070/PCIe/SSE2 NVIDIA Corporation 4.6.0 NVIDIA 537.58 **Blender Version** Broken: version: 4.1.0 Alpha, branch: main, commit date: 2023-11-01 18:56, hash: `ab9ce556a124` Worked: (unknown) **Short description of error** I have an addon that sets a few settings back after rendering using: ``` if bpy.app.version >= (3,3,0): if not (bpy.app.is_job_running('RENDER') or bpy.app.is_job_running('COMPOSITE')) : bpy.data.scenes['Scene'].cycles.samples = 256 bpy.data.scenes['Scene'].cycles.adaptive_min_samples = 16 bpy.data.scenes['Scene'].cycles.adaptive_threshold = 0.01 bpy.data.scenes['Scene'].cycles.use_adaptive_sampling = True ``` Very rarely I get a python error saying, can't write to cycles.samples in this context. I know it's not related to the screen context (what the mouse is over), so I'm guessing something inside of Blender still thinks it's either rendering or compsositing, despite me checking with the second line above. Once the error happens, it keeps happening after every render until I restart Blender. **Exact steps for others to reproduce the error** It's so intermittent, I don't think it's feasible to try and replicate. I'm hoping it will be obvious to those familiar with Cycles code which bit of C++ code would be responsible. If not, let me know and I'll create an addon that will repeatedly render until the error happens. I don't think this is the best idea, because sometimes it doesn't happen for months.

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labels 2023-11-03 13:27:35 +01:00

Germano Cavalcante commented 2023-11-03 13:52:21 +01:00

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The code you provided has a few issues.

• It has an extra "if" statement inside the condition.
• And it seems like it tries to change the samples while the Render and Compositing work is running. Isn't the intention the opposite?

As far as I can identify, it doesn't seem to prove that there is a bug in Blender.

Can't confirm.

The code you provided has a few issues. - It has an extra "if" statement inside the condition. - And it seems like it tries to change the `samples` while the Render and Compositing work is running. Isn't the intention the opposite? As far as I can identify, it doesn't seem to prove that there is a bug in Blender. Can't confirm.

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labels 2023-11-03 13:52:35 +01:00

michael campbell commented 2023-11-03 14:01:06 +01:00

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OK, it's just happened for the second time today. It seems to be happening more frequently with yesterdays build of Blender 4.1.

Here's the error:

 bpy.data.scenes[settings['Scene_Name']].cycles.samples = settings['Max_Samples']
AttributeError: Writing to ID classes in this context is not allowed: Scene, Scene datablock, error setting CyclesRenderSettings.samples

OK, it's just happened for the second time today. It seems to be happening more frequently with yesterdays build of Blender 4.1. Here's the error: ``` bpy.data.scenes[settings['Scene_Name']].cycles.samples = settings['Max_Samples'] AttributeError: Writing to ID classes in this context is not allowed: Scene, Scene datablock, error setting CyclesRenderSettings.samples ```

michael campbell commented 2023-11-03 14:03:03 +01:00

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Oh, sorry, I just quickly copied my actual code and modified it in the text editor here. The actual code doesn't have those mistakes. I'll correct it now above.

Oh, sorry, I just quickly copied my actual code and modified it in the text editor here. The actual code doesn't have those mistakes. I'll correct it now above.

michael campbell commented 2023-11-03 14:07:27 +01:00

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The actual code is a bit more complex. It queues up a function from the post render job handler using queue.queue(), and then uses the bpy.app.is_job_running to repeat the timer until not rendering/compositing, after which point it then set the samples.

The actual code is a bit more complex. It queues up a function from the post render job handler using queue.queue(), and then uses the bpy.app.is_job_running to repeat the timer until not rendering/compositing, after which point it then set the samples.

Germano Cavalcante commented 2023-11-03 14:12:58 +01:00

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To forward it to the developers, the triage team needs to confirm it first.

It is no convenient to put a task like this on the huge developer's to-do list:
"Review these functions in detail in the C++ code as they may possibly have a problem."

Many errors involving your own Python code will only be accepted as bugs if you are able to identify the error in Blender's code.

Finding that your code isn't working as expected in Blender isn't sufficient to consider it a Blender bug as there may be other reasons that aren't necessarily caused by errors in Blender's code.

To forward it to the developers, the triage team needs to confirm it first. It is no convenient to put a task like this on the huge developer's to-do list: "Review these functions in detail in the C++ code as they may possibly have a problem." Many errors involving your own Python code will only be accepted as bugs if you are able to identify the error in Blender's code. Finding that your code isn't working as expected in Blender isn't sufficient to consider it a Blender bug as there may be other reasons that aren't necessarily caused by errors in Blender's code.

michael campbell commented 2023-11-03 14:33:19 +01:00

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OK, well it's definitely not a problem with the Python code, otherwise it wouldn't happen only intermittently with the identical blend file and python code. It appears to be bpy.app.is_job_running is incorrect, or some other C++ variable that's checked against before allowing to write to the cycles settings, isn't being reset properly for a guess.

I'll create a small addon to replicate for you.

OK, well it's definitely not a problem with the Python code, otherwise it wouldn't happen only intermittently with the identical blend file and python code. It appears to be bpy.app.is_job_running is incorrect, or some other C++ variable that's checked against before allowing to write to the cycles settings, isn't being reset properly for a guess. I'll create a small addon to replicate for you.

👍 1

michael campbell commented 2023-11-03 20:34:43 +01:00

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@mano-wii Hi, sorry it took me a little while, I was rammed with work today.

The addon is attached and it's super simple to understand:

1. press ctl shift f12 to launch the bpy.ops.bugtest.repeat_render()
2. The operator will do the following. Store the users sample settings, set some random sample settings, launch render.render
3. At the end of each render the post render handler will add the function render_operations.render_post to queue.queue and start the timer so that it's executed when Blender returns to the main thread.
4. Once the time starts, it will run the function if bpy.app.is_job_running returns false for RENDER and COMPOSITE, if either is running it will just keep exiting the timer.
5. Once rendering/compositing completes, the timer will execute the function until it's successfull (maximum attempts of 11).
6. The function will revert the sample settings back to the original user settings and return true or false to indicate if it was successful.
7. if successful the timer will call the bugtest operator again before removing the timer.
8. if not it will retry a maximum of 11 times, and finally it will give a pop up message asking you to check the console, indicating the cycles context error has happened.

You can also cancel the render. The UI sample settings wont update until you wiggle your mouse over the panel.

You might have to leave it running a while.

It replicates exactly what the proper addon is doing, so even if you're unable to replicate the error due to how elusive it is, it should demonstrate that there's nothing wrong with the python code. When the error happens, neither the file or the python code have changed, which should indicate the issue is somewhere on the Blender side?

Cheers 👍

@mano-wii Hi, sorry it took me a little while, I was rammed with work today. The addon is attached and it's super simple to understand: 1. press ctl shift f12 to launch the bpy.ops.bugtest.repeat_render() 2. The operator will do the following. Store the users sample settings, set some random sample settings, launch render.render 3. At the end of each render the post render handler will add the function render_operations.render_post to queue.queue and start the timer so that it's executed when Blender returns to the main thread. 4. Once the time starts, it will run the function if bpy.app.is_job_running returns false for RENDER and COMPOSITE, if either is running it will just keep exiting the timer. 5. Once rendering/compositing completes, the timer will execute the function until it's successfull (maximum attempts of 11). 6. The function will revert the sample settings back to the original user settings and return true or false to indicate if it was successful. 7. if successful the timer will call the bugtest operator again before removing the timer. 8. if not it will retry a maximum of 11 times, and finally it will give a pop up message asking you to check the console, indicating the cycles context error has happened. You can also cancel the render. The UI sample settings wont update until you wiggle your mouse over the panel. You might have to leave it running a while. It replicates exactly what the proper addon is doing, so even if you're unable to replicate the error due to how elusive it is, it should demonstrate that there's nothing wrong with the python code. When the error happens, neither the file or the python code have changed, which should indicate the issue is somewhere on the Blender side? Cheers 👍

cycles context bug.zip

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labels 2023-11-03 20:41:10 +01:00

michael campbell commented 2023-11-03 20:44:29 +01:00

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Here's a scene to test the addon with.

By the way, I haven't been able to replicate the error again since this morning with my addon or this test addon, so you may need to leave it going for a while. The last time the error happened, it was with the identical scene that is now not generating the problem, so it appears to be not scene or addon related.

The problem is, there are thousands of users of the addon, so I'm contacted once or twice a month due to the volume of users, and I don't like to keep saying it's a problem with Blender that's so intermittent the Devs can't fix it.

If it's unfixable due to how intermittent it is, I'd be happy if anyone can suggest an alternative way of achieving the same (resetting the sample settings after rendering).

Here's a scene to test the addon with. By the way, I haven't been able to replicate the error again since this morning with my addon or this test addon, so you may need to leave it going for a while. The last time the error happened, it was with the identical scene that is now not generating the problem, so it appears to be not scene or addon related. The problem is, there are thousands of users of the addon, so I'm contacted once or twice a month due to the volume of users, and I don't like to keep saying it's a problem with Blender that's so intermittent the Devs can't fix it. If it's unfixable due to how intermittent it is, I'd be happy if anyone can suggest an alternative way of achieving the same (resetting the sample settings after rendering).

test mat problem.blend

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Andrea Donati commented 2023-11-04 19:45:17 +01:00

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I'm using 4.0, I don't know if it can be useful, but I'm having a similar problem with my addon that creates materials. If I insist on creating some bursts, I get the error "AttributeError: Writing to ID classes in this context is not allowed "

This almost always occurs (in fact I would say only) when the rendering engine is Cycles, but we are in Preview or Solid mode and not in Render Preview mode. However, if I am in Cycles mode with Render Preview Cycles or in Eevee mode with Eevee Preview Render mode, the problem almost never occurs.

I don't know, but for at least 2 years there has been an anomalous crash problem of this type between the 2 render modes, in fact I had made a patch on my addon that set the render mode automatically to bypass this crash when I applied the material, but now it is no longer just a crash, but it is also a context error.

There is also another error that appears in Console Blender, but I don't remember exactly what it's called, something like "context incorrect python this shouldn't happen" that appears from time to time

My invitation is to try testing in the various

Cycles modes: Solid-Preview-Render
Eevee: Solid-Preview-Render

I'm using 4.0, I don't know if it can be useful, but I'm having a similar problem with my addon that creates materials. If I insist on creating some bursts, I get the error "AttributeError: Writing to ID classes in this context is not allowed " This almost always occurs (in fact I would say only) when the rendering engine is Cycles, but we are in Preview or Solid mode and not in Render Preview mode. However, if I am in Cycles mode with Render Preview Cycles or in Eevee mode with Eevee Preview Render mode, the problem almost never occurs. I don't know, but for at least 2 years there has been an anomalous crash problem of this type between the 2 render modes, in fact I had made a patch on my addon that set the render mode automatically to bypass this crash when I applied the material, but now it is no longer just a crash, but it is also a context error. There is also another error that appears in Console Blender, but I don't remember exactly what it's called, something like "context incorrect python this shouldn't happen" that appears from time to time My invitation is to try testing in the various Cycles modes: Solid-Preview-Render Eevee: Solid-Preview-Render

michael campbell commented 2023-11-04 19:54:13 +01:00

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@Andrew_D thanks. For me it's happening even if the 3d viewport isn't visible, for example in the compositor workspace. It seems to have no pattern to it in my case, and the problem seems to always be when attempting to change the sample settings. It's as if Blender still thinks it's rendering, even though the bpy.app.is_job_running('RENDER') has already confirmed it isn't. It could be something completely different that's causing it, but this is my guess based on the error message I always get in the stack trace:

AttributeError: Writing to ID classes in this context is not allowed: Scene, Scene datablock, error setting CyclesRenderSettings.samples

@Andrew_D thanks. For me it's happening even if the 3d viewport isn't visible, for example in the compositor workspace. It seems to have no pattern to it in my case, and the problem seems to always be when attempting to change the sample settings. It's as if Blender still thinks it's rendering, even though the bpy.app.is_job_running('RENDER') has already confirmed it isn't. It could be something completely different that's causing it, but this is my guess based on the error message I always get in the stack trace: AttributeError: Writing to ID classes in this context is not allowed: Scene, Scene datablock, error setting CyclesRenderSettings.samples

Andrea Donati commented 2023-11-04 20:01:43 +01:00

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@3di

I understand, I also randomly get the same error when in my script I have to assign a node_group to a node like this:

my_node.node_tree = node_group

I got the same error as yours but for this situation as I indicated, Now I don't have the error at hand but today I've seen every one with this error AttributeError: Writing to ID classes in this context is not allowed

Never happened before a few builds ago of Blender 4.0 Beta

@3di I understand, I also randomly get the same error when in my script I have to assign a node_group to a node like this: `my_node.node_tree = node_group` I got the same error as yours but for this situation as I indicated, Now I don't have the error at hand but today I've seen every one with this error `AttributeError: Writing to ID classes in this context is not allowed` Never happened before a few builds ago of Blender 4.0 Beta

michael campbell commented 2023-11-04 21:36:12 +01:00

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Yep, something definitely changed during the last week to worsen the issue. Previously when it happened I could press ctrl z to undo and then it would work afterwards, but now once it happens, you have to restart Blender for it to not keep happening. 4.1 was fine around a week ago, no need to restart Blender.

Yep, something definitely changed during the last week to worsen the issue. Previously when it happened I could press ctrl z to undo and then it would work afterwards, but now once it happens, you have to restart Blender for it to not keep happening. 4.1 was fine around a week ago, no need to restart Blender.

Riccardo Fasoli commented 2023-11-07 23:27:31 +01:00

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i'm having the same issue using michael's addon in blender 3.6

i'm having the same issue using michael's addon in blender 3.6

Pratik Borhade commented 2023-11-14 07:44:41 +01:00

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Hi, I'm unable to redo the bug locally with provided script/addon and .blend file
Double check the steps I followed: open .blend file -> install/enable add-on -> start render with ctrl shift 12 (renders 1st frame in loop: repeat_render)

Also, it'd be helpful if you share the complete python traceback of error.

context incorrect
in this context is not allowed

I'm going through the script but haven't looked the every part yet. Maybe temp_override will help you if context is wrong?

Hi, I'm unable to redo the bug locally with provided script/addon and .blend file Double check the steps I followed: open .blend file -> install/enable add-on -> start render with ctrl shift 12 (renders 1st frame in loop: `repeat_render`) Also, it'd be helpful if you share the complete python traceback of error. > context incorrect > in this context is not allowed I'm going through the script but haven't looked the every part yet. Maybe `temp_override` will help you if context is wrong?

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labels 2023-11-14 07:44:56 +01:00

michael campbell commented 2023-11-14 14:59:56 +01:00

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Hi Patrick, thanks for looking. The temp_override isn't necessary because the addon is setting a property from bpy.data, not from bpy.context based on which editor the user's mouse is over.

The full python stack basically just show the queue code executed in queue_system.py, then line 37 of render_operations.py, followed immediately by the below error:

bpy.data.scenes[settings['Scene_Name']].cycles.samples = settings['Max_Samples']
AttributeError: Writing to ID classes in this context is not allowed: Scene, Scene datablock, error setting CyclesRenderSettings.samples

Hi Patrick, thanks for looking. The temp_override isn't necessary because the addon is setting a property from bpy.data, not from bpy.context based on which editor the user's mouse is over. The full python stack basically just show the queue code executed in queue_system.py, then line 37 of render_operations.py, followed immediately by the below error: ``` bpy.data.scenes[settings['Scene_Name']].cycles.samples = settings['Max_Samples'] AttributeError: Writing to ID classes in this context is not allowed: Scene, Scene datablock, error setting CyclesRenderSettings.samples ```

michael campbell commented 2023-11-14 15:21:24 +01:00

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By the way, the bug is extremely intermittent, it only happens once ever month or so for me, so you'll probably need to leave the script running quite a while.

Might be quicker to just figure out how it's possible for that context message to be triggered in a non context dependant operation.

By the way, the bug is extremely intermittent, it only happens once ever month or so for me, so you'll probably need to leave the script running quite a while. Might be quicker to just figure out how it's possible for that context message to be triggered in a non context dependant operation.

Pratik Borhade commented 2023-11-24 07:22:31 +01:00

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Hi, tried few time but unable to confirm it so far. I can understand this is important for add-on but fixing this problem gonna be quite difficult as we do not have quick way of reproducing the issue locally.

@lichtwerk , can you also check?

Hi, tried few time but unable to confirm it so far. I can understand this is important for add-on but fixing this problem gonna be quite difficult as we do not have quick way of reproducing the issue locally. @lichtwerk , can you also check?

michael campbell commented 2023-12-07 22:50:24 +01:00

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Hi, I've finally had a report from a user which has a bit more info. See attached.

Hi, I've finally had a report from a user which has a bit more info. See attached.

cycles render settings python update bug.txt

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michael campbell commented 2023-12-07 23:17:46 +01:00

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I've just found this online:

Some addon is likely using threads on the bpy api in a non-threadsafe manner (eg. not using locks).

The “internal state” is a counter that gets incremented / decremented when python runs in Blender. The message itself means the counter went below zero, which is a classic sign of a data race.

The thing is, my code is executed in queue.queue, which isn't reached until Blender returns to the main thread after rendering. I ran

print(threading.current_thread().name)

before trying to update the Cycles sample settings to make sure it was back on the main thread, and it was.

I've just found this online: > Some addon is likely using threads on the bpy api in a non-threadsafe manner (eg. not using locks). > > The “internal state” is a counter that gets incremented / decremented when python runs in Blender. The message itself means the counter went below zero, which is a classic sign of a data race. The thing is, my code is executed in queue.queue, which isn't reached until Blender returns to the main thread after rendering. I ran print(threading.current_thread().name) before trying to update the Cycles sample settings to make sure it was back on the main thread, and it was.

michael campbell commented 2023-12-07 23:22:51 +01:00

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Perhaps jacques lucke may know the cause, looks like he was battling this too back in 2015:

https://www.mail-archive.com/bf-committers@blender.org/msg20693.html

Perhaps jacques lucke may know the cause, looks like he was battling this too back in 2015: https://www.mail-archive.com/bf-committers@blender.org/msg20693.html

michael campbell commented 2024-02-09 05:05:00 +01:00

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Hi, this seems to be incorrectly set to needs information from user?

Hi, this seems to be incorrectly set to needs information from user?

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Pratik Borhade commented 2024-02-09 05:07:55 +01:00

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Hi, resetting the status. But we're still missing the reliable way for replicating the problem.

Hi, resetting the status. But we're still missing the reliable way for replicating the problem.

michael campbell commented 2024-02-09 05:17:37 +01:00

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Yes I think because it's so rare, this one can only be fixed based on the error messages rather than replication. Investigating how it's possible that context error could happen in a non context dependant operation. I'm assuming Jacques would have investigated quite thoroughly based on the link above when it was affecting his animation node addon.

Yes I think because it's so rare, this one can only be fixed based on the error messages rather than replication. Investigating how it's possible that context error could happen in a non context dependant operation. I'm assuming Jacques would have investigated quite thoroughly based on the link above when it was affecting his animation node addon.

michael campbell commented 2024-02-09 06:25:53 +01:00

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As far as I can tell, it only seems to happen when changing any cycles property after rendering (even though it's happening after returning to the main thread, and no attempt is made to modify the cycles properties until the below code confirms both the render and compositor have finished executing:

#below happens in queue.queue after returning to the main thread after rendering.
if bpy.app.version >= (3,3,0):
        if bpy.app.is_job_running('RENDER'):
            #print('render has still not completed')
            return 0.0001
        if bpy.app.is_job_running('COMPOSITE'):
            #print('compositing in progress')
            return 0.0001

And despite the error code below suggesting the Scene and Scene datablocks can't be written to:

AttributeError: Writing to ID classes in this context is not allowed: Scene, Scene datablock, error setting CyclesRenderSettings.samples

It seems they can, because the code is writing to those prior to the error happening:

#this code only executes only after bpy.app.is_job_running returns false for RENDER AND COMPOSITE
bpy.data.scenes[i['scene_name']].world = bpy.data.worlds[i['world_name']]
bpy.data.scenes[i['scene_name']].world.use_nodes = i['use_nodes']

#error happens on next line
bpy.data.scenes[settings['Scene_Name']].cycles.samples = settings['Max_Samples']

Hopefully that helps a little 👍

As far as I can tell, it only seems to happen when changing any cycles property after rendering (even though it's happening after returning to the main thread, and no attempt is made to modify the cycles properties until the below code confirms both the render and compositor have finished executing: ``` #below happens in queue.queue after returning to the main thread after rendering. if bpy.app.version >= (3,3,0): if bpy.app.is_job_running('RENDER'): #print('render has still not completed') return 0.0001 if bpy.app.is_job_running('COMPOSITE'): #print('compositing in progress') return 0.0001 ``` And despite the error code below suggesting the Scene and Scene datablocks can't be written to: ``` AttributeError: Writing to ID classes in this context is not allowed: Scene, Scene datablock, error setting CyclesRenderSettings.samples ``` It seems they can, because the code is writing to those prior to the error happening: ``` #this code only executes only after bpy.app.is_job_running returns false for RENDER AND COMPOSITE bpy.data.scenes[i['scene_name']].world = bpy.data.worlds[i['world_name']] bpy.data.scenes[i['scene_name']].world.use_nodes = i['use_nodes'] #error happens on next line bpy.data.scenes[settings['Scene_Name']].cycles.samples = settings['Max_Samples'] ``` Hopefully that helps a little 👍

michael campbell commented 2024-03-04 21:03:48 +01:00

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Hi, I've just had another report, but this time it's not due to a Cycles setting, it's happening when updating an image datablock:

bpy.data.scenes[scene_name].node_tree.nodes[cache_node_name].image.filepath = new_exr_path

Error:

 'AttributeError: Writing to ID classes in this context is not allowed: cache for Scene-Camera-ViewLayer, Image datablock, error setting Image.filepath\n']

Before attempting to update the image datablock's filepath, I'm ensuring the compositor and render have fully finished, and I'm launching the function from queue.queue() to make sure it's back on the main thread. I'm not sure why it's saying can't write in this context:

#runs from queue.queue() after rendering completes

if bpy.app.version >= (3,3,0):
        if bpy.app.is_job_running('RENDER'):
            #print('render has still not completed')
            return 0.0001
        if bpy.app.is_job_running('COMPOSITE'):
            #print('compositing in progress')
            return 0.0001

bpy.data.scenes[scene_name].node_tree.nodes[cache_node_name].image.filepath = new_exr_path

Hi, I've just had another report, but this time it's not due to a Cycles setting, it's happening when updating an image datablock: ```bpy.data.scenes[scene_name].node_tree.nodes[cache_node_name].image.filepath = new_exr_path``` Error: ``` 'AttributeError: Writing to ID classes in this context is not allowed: cache for Scene-Camera-ViewLayer, Image datablock, error setting Image.filepath\n'] ``` Before attempting to update the image datablock's filepath, I'm ensuring the compositor and render have fully finished, and I'm launching the function from queue.queue() to make sure it's back on the main thread. I'm not sure why it's saying can't write in this context: ``` #runs from queue.queue() after rendering completes if bpy.app.version >= (3,3,0): if bpy.app.is_job_running('RENDER'): #print('render has still not completed') return 0.0001 if bpy.app.is_job_running('COMPOSITE'): #print('compositing in progress') return 0.0001 bpy.data.scenes[scene_name].node_tree.nodes[cache_node_name].image.filepath = new_exr_path ```

michael campbell commented 2024-03-04 21:10:55 +01:00

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Just to re-iterate, this isn't a constant error, it happens intermittently with identical blend files. Occasionally, once it's happened it may continue happening every render until Blender is restarted. Then the identical Blend file will no longer cause the error.

It's super annoying because although it only happens extremely rarely, on a monthly basis I get one or two reports due to their being around 5000 users. And it's the only problem the addon encounters 😕

Just to re-iterate, this isn't a constant error, it happens intermittently with identical blend files. Occasionally, once it's happened it may continue happening every render until Blender is restarted. Then the identical Blend file will no longer cause the error. It's super annoying because although it only happens extremely rarely, on a monthly basis I get one or two reports due to their being around 5000 users. And it's the only problem the addon encounters 😕

michael campbell referenced this issue 2024-03-05 18:51:25 +01:00

Image Access in Compositor Backdrop is not thread-safe #118337

michael campbell commented 2024-03-05 18:55:12 +01:00

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Sergey just gave some advice on this if it helps? #118337 (comment)

Sergey just gave some advice on this if it helps? https://projects.blender.org/blender/blender/issues/118337#issuecomment-1138762

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Reference: blender/blender#114455

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