VSCode stuck on fetching cargo metadata, even without dependencies

[SeseMueller]

The rust-analyzer in VSCode runs into an infinite loop of fetching cargo metadata in the latest version.
It happened after I updated to Rust 1.88 and at first blamed the macros of my own project, but managed to reproduce the error on a VSCode Profile with only the rust-analyzer extension installed, in a freshly initialized folder.
Edit: running rustup override set 1.87(or 1.80) does not fix it, so it's most likely not a version problem.

rust-analyzer version: rust-analyzer version: 0.4.2525-standalone (2d518c73d9 2025-07-05) [/Users/USERNAME/.vscode/extensions/rust-lang.rust-analyzer-0.4.2525-darwin-arm64/server/rust-analyzer]
(Pre-release has the same version and same problem)

rustc version: rustc 1.88.0 (6b00bc388 2025-06-23)

editor or extension: VSCode, latest version; rust-analyzer extension version: 0.3.2519

relevant settings: Only $RUSTC_WRAPPER=/Path/to/sccache.

repository link (if public, optional): Default rust hello world; cargo init

code snippet to reproduce:

mkdir test
cd test
cargo init
code .
(Then enter a profile with only the rust-analyzer)

I'm honestly not sure what I am doing wrong; I expect this to have to do something with something of my setup, else this should have happened to quite a few more people yet.
I did record the logs for this:

https://pastebin.com/tfTWELhU
(And yes, this also happens outside of the ~/Desktop folder.)

It's making work on my Rust projects basically impossible because the CPU is caught up with fetching metadata and the results only show for a fraction of a second before the next fetch starts.

[ShoyuVanilla]

In a quick glance, copied lockfiles are watched by vfs somehow and re-triggering metadata fetch, which causes another write on copied lockfiles -> infinite loop 🤔

[ShoyuVanilla]

I'm on my phone right now so cannot take a serious look into this but here's my hypothesis:

• We might have been suffering this "watched lockfile problem" for moments
• But for normal projects, this might not be noticeable since lockfiles are copied from the workspace root, which is updated via other processes like cargo commands from user or flychecks triggered by rust-analyzer itself, so no further updates in lockfiles
• But if a sysroot dependencies are updated via toolchain updates, rust-analyzer tries to update the sysroot lockfile cached by itself and this infinite loop happens, since there is no "original lockfile" that can be updated by other processes
• Possible solutions: Make our vfs to ignore updates on copied lockfiles, or we might have to fix somewhere on sysroot metadata fetch routine to prevent this infinite loop

I might be wrong but it will take some time to check this because I'm outside now 😢

[SanchayanMaity]

Not sure what is the real problem, but, FWIW, was running into the same issue with neovim + rust-analyzer. Even cargo build would be stuck. ps aux | grep rust would point to cargo metadata. Adding the below to cargo config helped.

[net]
git-fetch-with-cli = true

[SeseMueller]

[net]
git-fetch-with-cli = true

Thanks for the suggestion, but this didn't fix it. Your issue is most likely different; for me cargo build does work, I can even get a Hello, world! output. And there are no hogging cargo metadata in the processes.

[ShoyuVanilla]

Not sure what is the real problem, but, FWIW, was running into the same issue with neovim + rust-analyzer. Even cargo build would be stuck. ps aux | grep rust would point to cargo metadata. Adding the below to cargo config helped.

[net]
git-fetch-with-cli = true

I guess your problem might be different, as this one seems infinite loop of re-triggering cargo metadata but yours seems cargo failing to fetch some dependencies, as net.git-fetch-with-cli helps.
Do you have dependencies from some private git repositories in your workspace?

[ShoyuVanilla]

I'm honestly not sure what I am doing wrong; I expect this to have to do something with something of my setup, else this should have happened to quite a few more people yet.

Bit more information would help figuring this out.
So, I'd like to ask some details:

• I guess this wasn't happening before updating rust to 1.88.0, right? Then this happened after you just updated it, even though you didn't update rust-analyzer?
• Could you let me know your rust-analyzer settings?

[SeseMueller]

Do you have dependencies from some private git repositories in your workspace?

No, I get this issue right after cargo init without any changes to the code.

I guess this wasn't happening before updating rust to 1.88.0, right? Then this happened after you just updated it, even though you didn't update rust-analyzer?

Yes, that's correct, if I remember correctly.

Could you let me know your rust-analyzer settings?

I am using a newly installed rust-analyzer extension, with no settings changed.

If it could help track down the issue, I could try a fresh VSCode install.

[ShoyuVanilla]

Do you have dependencies from some private git repositories in your workspace?

No, I get this issue right after cargo init without any changes to the code.

Oh, this question was for SanchayanMaity 😄

Anyway, thanks for the answers. It helps a lot!

Trying fresh new vs-code install wouldn't be so fruitful since you don't have any settings changed.

Not sure this would help or not but clearing your cargo registry cache - in most cases, it's ~/.cargo/registry and deleting this directory is totally safe - might make things work, I guess

[SeseMueller]

Oh sorry, I misunderstood.
Deleting the registry did not fix it sadly.

[ShoyuVanilla]

Oh, that doesn't work 🤔
Does running rustup override set 1.87.0 (or your previous rust toolchain version before updating to 1.88.0) and restarting vs-code help?

[SeseMueller]

No, also not; Neither with rustup override set 1.80, so it's probably not a version problem.

[ShoyuVanilla]

Then I guess this happened by auto update of rust-analyzer vs-code plugin, as auto update option is enabled by default in vs-code.
Another possible action is trying previous stable releases, like current newest version number -2 or current newest version number -3

[SeseMueller]

I'll try it.

Trying releases: 0.3.2457 good 0.3.2490 good, 0.3.2509 good, 0.3.2519 good,

That's weird. Can I even reproduce?
0.4.2525 good. That's bad, that was the version I previously had problems with.
Can I reproduce with the official version previously? (0.3.2527)
Nope.

Lastly, does it work again on my larger projects?
Yes, it works again. 0.4.2526.
Weird.

I'll recollect the details from above:
rust-analyzer version: rust-analyzer version: 0.4.2525-standalone (2d518c7 2025-07-05) [/Users/USERNAME/.vscode/extensions/rust-lang.rust-analyzer-0.4.2525-darwin-arm64/server/rust-analyzer]
rustc version: rustc 1.88.0 (6b00bc388 2025-06-23)
I guess I set the CARGO_HOME??

Given that I can't find anyone else with the same issue, I'll blame it on a faulty install somehow.

After running through multiple versions of the rust-analyzer, I cannot reproduce the error, even with the same version.
And also the same rustc version; nothing changed.

Closing as cannot reproduce.