bootstrap: build locking doesn't work any more

[jyn514]

I tried this code:

x t tidy & x t tidy

I expected to see this happen: Bootstrap is built, and one process runs tidy while the other says "waiting for build lock"

Instead, this happened:

; x t tidy & x t tidy 
[1] 34539
Building bootstrap
Building bootstrap
    Blocking waiting for file lock on build directory
    Finished dev [unoptimized] target(s) in 0.20s
    Finished dev [unoptimized] target(s) in 0.24s
Building tool tidy (stage0)
warning: creating symbolic link `/Users/jyn/src/rust/build/aarch64-apple-darwin/stage0-sysroot/lib/rustlib/src/rust` to `/Users/jyn/src/rust` failed with File exists (os error 17)
warning: creating symbolic link `/Users/jyn/src/rust/build/aarch64-apple-darwin/stage0-sysroot/lib/rustlib/rustc-src/rust` to `/Users/jyn/src/rust` failed with File exists (os error 17)
Building tool tidy (stage0)
    Finished release [optimized] target(s) in 0.98s
fmt check
    Finished release [optimized] target(s) in 1.14s
fmt check

Meta

HEAD is branched from 90a9f69.

; uname -a
Darwin jyns-MacBook-Pro 22.4.0 Darwin Kernel Version 22.4.0: Mon Mar  6 20:59:28 PST 2023; root:xnu-8796.101.5~3/RELEASE_ARM64_T6000 arm64

[jyn514]

I do have a build/lock file, but apparently flock isn't working correctly?

[jyn514]

@miguelraz also ran into this on Linux. I'm starting to think locking is just completely broken.

[Ezrashaw]

I can confirm it doesn't seem to work on linux. Although it is important to note that cargo still correctly locks, so most things should de-duplicate from cargo anyway.

[jyn514]

No, bootstrap has its own locking issues separate from cargo because it deletes and recreates the sysroot. See #76661.

[Ezrashaw]

Ahh, I'm just seeing the behaviour you saw here. At least x t tidy times 2 doesn't crash and burn lol.

[albertlarsan68]

Well... It may very well be #108607🤦. I see a quick fix, just move the lock guard back out of the block.

[fee1-dead]

This might be the cause of supposed "incremental errors" that has occurred to me when rust-analyzer and the command line is running at the same time.