Lock

[…] alas! either the locks were too large, or the key was too small, but at any rate it would not open any of them. – Lewis Carroll, Alice’s Adventures in Wonderland The Long-Standing Issue rustup#988 is probably one of the oldest open issues in the whole history of the rustup project, filed by no other than @matklad when he was working on Intellij Rust. As it turned out, rustup the toolchain manager did not have a proper locking mechanism to prevent concurrent invocation of its commands. The original issue explicitly mentioned that two concurrent rustup component add invocations (i.e. writing modifications) would cancel each other out with an error. ...