Change:
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Using a small sample extension I could see that the folding provider is hit twice per document change by the folding implementation by sticky scroll, if there's no document symbol provider for that language. It's also possible to request folding ranges from extensions using the command. You can debug that in the dev tools by setting a breakpoint here: Sample extension:
I thought I could help by trying a between (I don't remember seeing this issue last fall) and current , but I with the latest and , the problem(s) are still there, only the listener leak properly points to sticky scroll (while in main, the messages are a bit less helpful and provide an unrelated trace?): The listener leak + redundant folding ranges do seem to come together though.
Verified that both folding and sticky scroll correctly cancel their requests.
So I think on our side all works as expected. If you see more requests, it would be great if you can debug this in the dev tools to see where the requests come from. Look at the document version as well. It's possible on our side to reduce the number of requests by having sticky scroll using the result from the folding request. But as these are separate features and can be turned on/off separately, it's not trivial. As a language server you need to be ready to get multiple requests. Caching results is best done on the language server side. I would think you keep the AST around as it's needed for different type of requests.
Our team believes this is a VS Code bug still -- we're seeing the number of folding ranges grow exponentially every time the active document changes, so eventually our extension becomes unusable due having to process an "endless" number (thousands) of these requests. But there might be a limit to the number of requests, maybe 100 per visible file? The issue doesn't always repro though. Seems to repro more frequently with blank files, not 100% sure of the requirements yet. A PR to remove our "workaround" is at -- without that workaround it triggers the exponentially increasing folding ranges request.
It appears the repro of exponentially increasing get folding ranges requires 1 document to be visible at once. With 2 documents visible, I'm seeing it exponentially increase, but max out at 526 requests -- per active document change. <img width="369" alt="image" src=""That happens until this is hit: <img width="506" alt="image" src=""after which no more get folding ranges requests are sent.
I tried with multiple editors visible, also some editors showing the same file, but can not see the number of requests increasing to more than 2 requests per modified editor. create an extension () with the code snippet . add to the run VS Code with the extension and create some files open one or more java files in editors make some changes in a Java file and observe in the dev tools console that there are 2 folding provider requests fired per document change disable folding with and and verify that there are no longer requests fired. If you can come up with similar reproducible steps that would be great. Maybe check if some other extension is installed that makes requests.
does the exponential increase in requests happen with applied too, or only without? Because if it's only without, I did notice an issue with the promise resolve in: : which should probably look more like this (return the promise resolution result instead of the actual promise):
Hi . To clarify, we repro with the (simple) code The issue appears to be related to , which your example did not exercise. I can reproduce the issue easily with the following simple extension. Switching back and forth between two open java files (both simultaneously visible), and running the "Hello World" command, I see that refresh triggers more and more requests each time.

Discussion:
return null; } <del> protected createModelFromProvider(textModel: TextModel, modelVersionId: number, token: CancellationToken): Promise<FoldingRegions> { </del> <ins> protected async createModelFromProvider(textModel: TextModel, modelVersionId: number, token: CancellationToken): Promise<FoldingRegions> { </ins> const provider = new IndentRangeProvider(textModel, this._languageConfigurationService, this._foldingLimitReporter); <del> return provider.compute(token); </del> <ins> try { return await provider.compute(token); } finally { provider.dispose(); } </ins> } }

protected createModelFromProvider(textModel: TextModel, modelVersionId: number, token: CancellationToken): Promise<FoldingRegions | null> { const selectedProviders = FoldingController.getFoldingRangeProviders(this._languageFeaturesService, textModel); const provider = new SyntaxRangeProvider(textModel, selectedProviders, () => this.createModelFromProvider(textModel, modelVersionId, token), this._foldingLimitReporter, undefined); <del> return provider.compute(token); </del> <ins> try { return provider.compute(token); } finally { provider.dispose(); } </ins> } }