rust-lang / rust-lang/rustup

rustc --print sysroot can be slow

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Dominant language
Rust
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Description

Hi!

Looks like sometimes rustc --print sysroot can take as long as three seconds to complete. I think this a bit too much, and I suppose that rustup is to blame. See https://github.com/intellij-rust/intellij-rust/issues/754#issuecomment-255958020 for example of this issue. We've raised timeout to five seconds in IntelliJ Rust, so this shouldn't be a problem, but it seems fishy anyway!

Many thanks to @la10736 for investigating this issue!

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First steps

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Research direction

Start by reproducing the timing of rustc --print sysroot, then read the linked IntelliJ Rust issue comment for the existing investigation. Trace which rustup entry point handles this command and compare slow and fast runs. Done means identifying the cause of the delay and confirming that the command completes within an acceptable time.

Written by the indexing model from the issue text.

Assessment

Tech stack
rust
Domain
performance, tooling
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
35/100

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