microsoft / microsoft/vscode-cpptools

Edits inside a function can cause a big increase in IntelliSense update time

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#13,064 2 comments 0 reactions 0 assignees View on GitHub

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bug Language Service performance Visual Studio Works in VS
Dominant language
TypeScript
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Description

I have a repro with 3.2k functions that each calls another function (generated with the help of Copilot), and after just 4 edits it starts taking around 8 times as long to update the TU. I don't repro the same behavior in VS. The processing time goes down to the original update time after a save.

It seems to repro for all TUs in general after enough edits are made, but the particular repro case seems like a "worst case" for some reason.

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First steps

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  3. Fork the repository and make your change on a branch.
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Research direction

The payload names no source files or tests. Start by reproducing the 3.2k-function chained-call case in vscode-cpptools, measuring TU update time after successive edits and after saving, and comparing with VS. Done means the edit path no longer shows the reported growth while retaining correct IntelliSense updates.

Written by the indexing model from the issue text.

Assessment

Tech stack
cpp, typescript
Domain
performance, tooling
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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