Error when loading GLB : this._layersToFinalize.push is not a function

[magmerionKwa]

Describe the bug
Sometime loading a GLB generate an exception that block the rendering process and keep the process spinner to 1

To Reproduce
Steps to reproduce the behavior:

1. Create a GLTF loader
2. Load a GLB
   Random error - sometimes it works and sometime we have an exception

Expected behavior

• The model should be loaded
• Or if an error happen then the exception should be catch and the spinner process should go back to 0

Screenshots
Exception when loading GLB :

main.361f5a13.js?ver=361f5a134270ae4b1cb7&t=1771509779284:514712 Uncaught (in promise) TypeError: this._layersToFinalize.push is not a function
    at SceneModel._getVBOBatchingLayer (main.361f5a13.js?ver=361f5a134270ae4b1cb7&t=1771509779284:514712:28)
    at SceneModel._createMesh (main.361f5a13.js?ver=361f5a134270ae4b1cb7&t=1771509779284:514485:27)
    at SceneModel.createMesh (main.361f5a13.js?ver=361f5a134270ae4b1cb7&t=1771509779284:514459:17)
    at parseNodeMesh (main.361f5a13.js?ver=361f5a134270ae4b1cb7&t=1771509779284:544371:22)
    at main.361f5a13.js?ver=361f5a134270ae4b1cb7&t=1771509779284:544207:9
    at Array.forEach (<anonymous>)
    at createSceneMeshesAndEntities (main.361f5a13.js?ver=361f5a134270ae4b1cb7&t=1771509779284:544195:11)
    at loadDefaultScene (main.361f5a13.js?ver=361f5a134270ae4b1cb7&t=1771509779284:544232:5)
    at main.361f5a13.js?ver=361f5a134270ae4b1cb7&t=1771509779284:543937:5

viewer.scene.canvas.spinner.processes
-> 1

Code used to load the GLB with the try catch :

export function loadModel(
    loaders: LoadersType,
    modelConfig: ModelConfig,
    coords?: number[],
    callback?: (model: any) => void,
    callbackOptions?: {
        onSuccessModelLoaded?: (
            model: VBOSceneModel,
            modelConfig: ModelConfig
        ) => void;
        onErrorLoadingModel?: (modelConfig: ModelConfig) => void;
    }
) {
    return new Promise<VBOSceneModel>(async (resolve, reject) => {
        const loader = loaders[modelConfig.extension || 'xkt'];

        if (!loader) {
            reject('NO_LOADER_FOUND');
            return;
        }

        const options: any = {
            id: modelConfig.id,
            src: modelConfig.modelSrc,
            edges: modelConfig.extension === 'xkt',
            globalizeObjectIds: true,
            origin: coords,
            colorTextureEnabled: true,
            backfaces: false,
        };
        const { viewer } = loader;

        if (coords) {
            options.origin = coords;
        }

        try {
            const model = loader.load(options);
            callback?.(model);

            model?.on('loaded', () => {
                viewer.fire('modelLoaded', { model, modelConfig });
                callbackOptions?.onSuccessModelLoaded?.(model, modelConfig);
                resolve(model);
            });
            model?.on('error', (error: any) => {
                console.log('Model failed to load:', modelConfig);
                viewer.fire('modelFailed', model);
                // callbackOptions?.onErrorLoadingModel?.(modelConfig);
                reject(MODEL_ON_LOAD_ERROR);
            });
        } catch (error) {
            console.error('Error loading model :', error);
            reject(error);
        }
    });
}

Additional context
We want to understand what this error mean and how to manage it

[MichalDybizbanskiCreoox]

Hi @magmerionKwa, what xeokit-sdk's version are you using?

[magmerionKwa]

Hello @MichalDybizbanskiCreoox,

We are using "@xeokit/xeokit-sdk": "2.6.66"

[MichalDybizbanskiCreoox]

Hi @magmerionKwa,
In the 2.6.66 version the SceneModel::destroy method assigns an empty {} object to the instance's _layersToFinalize property at

xeokit-sdk/src/viewer/scene/model/SceneModel.js

Line 3990 in 277cfcb

this._layersToFinalize = {};

This would suggest, that in your application there's some kind of a race condition, that results in a SceneModel::destroy call before that instance is finalized.
So far we haven't encountered this issue in other integrations, so I'd first try to investigate, whether the function that is passed as the loadModel's callback argument doesn't do something to its model argument (which at the call time is not finalized yet) that results in the destroy call.
Alternatively - perhaps there's some other object's destroy (like a Viewer etc) method being called, that triggers the model's destroy, before it's fully loaded and finalized.
One way to determine that would be to set a breakpoint inside the SceneModel::destroy method, and see what calls it.
Best,
Michał