Significant delay on check-on-save after loading workspace, and for some files it never triggers

[RalfJung]

To reproduce:

• open Miri in RA
• wait until the "budy" indicator at the bottom of the windows disappears
• change some file and hit Ctrl-S

Expected behavior:

• the check build starts pretty much immediately, with a "busy" indicator at the bottom of the window

Actual behavior:

• it can take 15s until the "busy" indicator appears and the check build actually starts

I think that's new; check builds used to be pretty responsive always, even immediately after loading a workspace.

rust-analyzer version: rust-analyzer version: 0.3.2257-standalone [/home/r/.vscode-oss/extensions/rust-lang.rust-analyzer-0.3.2257-linux-x64/server/rust-analyzer]

rustc version: very recent nightly

editor or extension: VSCodium, extension v0.3.2257

relevant settings:

{
    "rust-analyzer.rustc.source": "discover",
    "rust-analyzer.linkedProjects": [
        "Cargo.toml",
        "cargo-miri/Cargo.toml",
        "miri-script/Cargo.toml",
    ],
    "rust-analyzer.check.invocationLocation": "root",
    "rust-analyzer.check.invocationStrategy": "once",
    "rust-analyzer.check.overrideCommand": [
        "env",
        "MIRI_AUTO_OPS=no",
        "./miri",
        "clippy",
        "--message-format=json",
    ],
    // Contrary to what the name suggests, this also affects proc macros.
    "rust-analyzer.cargo.buildScripts.invocationLocation": "root",
    "rust-analyzer.cargo.buildScripts.invocationStrategy": "once",
    "rust-analyzer.cargo.buildScripts.overrideCommand": [
        "env",
        "MIRI_AUTO_OPS=no",
        "./miri",
        "check",
        "--message-format=json",
    ],
}

    "rust-analyzer.lens.enable": false,
    "rust-analyzer.cachePriming.enable": false,
    "rust-analyzer.cargo.buildScripts.useRustcWrapper": false, // https://github.com/rust-lang/rust-analyzer/issues/14722
    "rust-analyzer.diagnostics.disabled": [
        "unlinked-file",
        "macro-error" // trouble with the xshell `cmd!` macro
    ],

repository link (if public, optional): https://github.com/rust-lang/miri/

[RalfJung]

Just waiting a while doesn't always seem to help, but I don't understand what helps... I'm playing around with things randomly and at some point check builds start to happen. Very strange.

[RalfJung]

At least for Miri it seems to have to do with which file I am saving. Saving miri-script/src/commands.rs is entirely ignored, but saving src/shims/unix/linux_like/epoll.rs eventually triggers a build. Is RA trying to figure out whether the file belongs to the project and that somehow goes wrong?

[Veykril]

Is RA trying to figure out whether the file belongs to the project and that somehow goes wrong?

Most likely this

[RalfJung]

The odd this is that this used to work, a few months ago. I couldn't find recent changes mentioning check-on-save, but maybe I searched for the wrong keywords.

[RalfJung]

Okay so actually I think there are two issues here:

• For files in src/, if I save a file shortly after opening the workspace, it takes ~15s until it even starts doing the check build (or at least, until the "busy" indicator appears)
• For files outside src/, it never starts a check build; not even if the file is contained in one of the other linkedProjects

Should I report one of these as a separate issue?