TreeDataProvider shows error "Element with id is already registered"

[ejizba]

Issue Type: Bug

We've noticed errors similar to the following when leveraging the TreeDataProvider in our extensions:

I believe it's a race condition when refreshing and I've created a simple extension that you can clone in order to repro. Specifically, the 'ej/tree' branch:
https://github.com/EricJizbaMSFT/helloworldext/tree/ej/tree

In order to repro, right click on the "1" node and select "Hello world":

This repros for me on both insiders and non-insiders.

VS Code version: Code - Insiders 1.33.0-insider (0ac1114, 2019-04-01T15:47:22.304Z)
OS version: Darwin x64 18.2.0

System Info

Item	Value
CPUs	Intel(R) Core(TM) i7-4870HQ CPU @ 2.50GHz (8 x 2500)
GPU Status	2d_canvas: enabled checker_imaging: disabled_off flash_3d: enabled flash_stage3d: enabled flash_stage3d_baseline: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on native_gpu_memory_buffers: enabled rasterization: enabled surface_synchronization: enabled_on video_decode: enabled webgl: enabled webgl2: enabled
Load (avg)	2, 2, 2
Memory (System)	16.00GB (2.34GB free)
Process Argv	.
Screen Reader	no
VM	0%

Extensions (7)

Extension	Author (truncated)	Version
Ionide-fsharp	Ion	3.35.0
vscode-azurefunctions	ms-	0.16.0
python	ms-	2019.3.6352
azure-account	ms-	0.8.1
csharp	ms-	1.18.0
java	red	0.42.1
vscode-java-debug	vsc	0.17.0

[eamodio]

I see this a lot in GitLens too, but I haven't been able to pinpoint a scenario that always repro's it.

[eamodio]

I was really hoping that when the custom views adopted the new tree implementation this issue would go away -- but I still see it 😢

[sandy081]

@eamodio Can you please provide steps to repro it?

[ejizba]

@sandy081 I've confirmed it still repros with my original steps provided in the first comment above

Version: 1.37.0-insider
Commit: 8fa8111
Date: 2019-07-12T09:17:10.495Z
Electron: 4.2.5
Chrome: 69.0.3497.128
Node.js: 10.11.0
V8: 6.9.427.31-electron.0
OS: Darwin x64 18.6.0

[mikepsinn]

Thanks for all your great work on this project! :D

I can reproduce with this project on:
OS: Windows 10
Node Version: v8.11.2
Xcode version: Not installed

• Clone https://github.com/QuantiModo/quantimodo-android-chrome-ios-web-app
• yarn install
• Install Gulp VSCode extension
• Click refresh button that appears here
  

Then I get
Element with id gulpfile.js:current git branch: develop is already registered
and it doesn't show the gulp tasks.

notificationsAlerts.ts:38 Error: Element with id gulpfile.js:current git branch: develop is already registered
	at p.createAndRegisterTreeNode (k:\Users\m_000\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\workbench\services\extensions\node\extensionHostProcess.js:488:50)
	at define.fetchChildrenNodes.a.asPromise.then.Promise.all.u.coalesce.map.a.asPromise.then.n (k:\Users\m_000\AppData\Local\Programs\Microsoft VS Code\resources\app\out\vs\workbench\services\extensions\node\extensionHostProcess.js:486:763)

Any suggestions? Thanks! :D

CPUs	AMD FX(tm)-6300 Six-Core Processor (6 x 3516)
GPU Status	2d_canvas: enabledflash_3d: enabledflash_stage3d: enabledflash_stage3d_baseline: enabledgpu_compositing: enabledmultiple_raster_threads: enabled_onnative_gpu_memory_buffers: disabled_softwareoop_rasterization: disabled_offprotected_video_decode: unavailable_offrasterization: enabledskia_deferred_display_list: disabled_offskia_renderer: disabled_offsurface_synchronization: enabled_onvideo_decode: enabledviz_display_compositor: disabled_offwebgl: enabledwebgl2: enabled
Load (avg)	undefined
Memory (System)	23.97GB (8.81GB free)
Process Argv
Screen Reader	no
VM	0%

Extension	Author (truncated)	Version
prettier-vscode	esb	1.9.0
ginfuru-vscode-jekyll-syntax	gin	0.1.0
vscode-jekyll-snippets	gin	0.9.1
vscode-back-forward-button	gri	0.1.2
beautify	Hoo	1.5.0
mark-as-excluded	jcm	0.2.6
vscode-html-format	moh	0.0.3
gulptasks	nic	1.3.1
jekyll	ost	0.1.1
ruby	reb	0.24.1
vscode-yaml	red	0.4.1
sort-lines	Tyr	1.8.0
vscodeintellicode	Vis	1.1.7
JavaScriptSnippets	xab	1.7.2

[nbransby]

Im getting this a lot too. Could I confirm if this error message was intended for the extension developer due to incorrect use of the vscode API or an internal assertion?

[alexr00]

I can repro with the original example from @EricJizbaMSFT (thank you for the concise example!). I'm looking into it.

[alexr00]

The example nicely shows that we don't do anything to prevent multiple tree refreshes from occurring at the same time. I've added refresh queuing. If you seen any odd tree behavior in the near future, it could be that this queuing broke some other timing.