component download failed under parallel

[loynoir]

Verification

• I searched for recent similar issues at https://github.com/rust-lang/rustup/issues?q=is%3Aissue and found no duplicates.
• I am on the latest version of Rustup according to https://github.com/rust-lang/rustup/tags and am still able to reproduce my issue.

Problem

component download failed under parallel

Steps

component download failed under parallel

$ rm -rf ~/.rustup && fd Cargo.toml -x env -C {//} cargo build
info: syncing channel updates for ...
info: latest update on ... for version ...
info: downloading ... components
info: rolling back changes
error: component download failed for clippy-x86_64-unknown-linux-gnu: could not rename 'downloaded' file from '~/.rustup/downloads/fea05854f7f99eab2551578ac013c7159d9679ea657e45516bdb0c31906cf90d.partial' to '~/.rustup/downloads/fea05854f7f99eab2551578ac013c7159d9679ea657e45516bdb0c31906cf90d': No such file or directory (os error 2): No such file or directory (os error 2)
info: syncing channel updates for ...
info: latest update on ... for version ...
info: downloading ... components
info: rolling back changes
error: component download failed for clippy-x86_64-unknown-linux-gnu: could not rename 'downloaded' file from '~/.rustup/downloads/fea05854f7f99eab2551578ac013c7159d9679ea657e45516bdb0c31906cf90d.partial' to '~/.rustup/downloads/fea05854f7f99eab2551578ac013c7159d9679ea657e45516bdb0c31906cf90d': No such file or directory (os error 2): No such file or directory (os error 2)
info: syncing channel updates for ...
info: latest update on ... for version ...
info: downloading ... components
info: rolling back changes
error: component download failed for cargo-x86_64-unknown-linux-gnu: could not rename 'downloaded' file from '~/.rustup/downloads/c5421d7fad5e5c3596ba6c0748e4441a87deb237a56e1ef7c1551c0dc93dd3cd.partial' to '~/.rustup/downloads/c5421d7fad5e5c3596ba6c0748e4441a87deb237a56e1ef7c1551c0dc93dd3cd': No such file or directory (os error 2): No such file or directory (os error 2)
info: syncing channel updates for ...
info: latest update on ... for version ...
info: downloading ... components
info: rolling back changes
error: component download failed for clippy-x86_64-unknown-linux-gnu: could not rename 'downloaded' file from '~/.rustup/downloads/fea05854f7f99eab2551578ac013c7159d9679ea657e45516bdb0c31906cf90d.partial' to '~/.rustup/downloads/fea05854f7f99eab2551578ac013c7159d9679ea657e45516bdb0c31906cf90d': No such file or directory (os error 2): No such file or directory (os error 2)

Possible Solution(s)

workaround component download failed by not parallel

$ rm -rf ~/.rustup && for dir in $(fd Cargo.toml -x echo {//}); do env -C "$dir" cargo build; done
info: syncing channel updates for ...
info: latest update on ... for version ...
info: downloading ... components
    Updating `...` index
  Downloaded ... ... (registry `...`)
...
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.20s

Notes

No response

Rustup version

rustup 1.29.0

Installed toolchains

$ rm -rf ~/.rustup

OS version

nixos

[cachebag]

Can you confirm that all of the parallel cargo build invocations share the same RUSTUP_HOME and are auto-installing the same toolchain after rm -rf ~/.rustup? Also, does preinstalling the toolchain once before the parallel builds avoid the issue?

This looks like a race in the shared download cache: parallel processes can try to use the same <hash>.partial path, and one can rename or clean it up while another is still expecting it to exist.

rustup/src/dist/download.rs

Lines 85 to 89 in ed94f61

	let mut download = DownloadOptions::try_from(self.process)?
	.start(url, &partial_file_path)
	.with_hasher(&mut hasher)
	.with_status(status)
	.with_resume();

and it looks like the reported error here shows up when download.rs tries to rename the same shared partial path

rustup/src/dist/download.rs

Lines 118 to 122 in ed94f61

	utils::rename(
	"downloaded",
	&partial_file_path,
	&target_file,
	self.permit_copy_rename,

[rami3l]

@cachebag Thanks for the reply! This is very likely another duplicate of #988...

[loynoir]

Tested with

#!/bin/bash

set -xeuo pipefail

unset CARGO_HOME RUSTUP_HOME

echo === 1 ===
rm -rf ~/.rustup ~/.cargo
for dir in $(fd Cargo.toml -x echo '{//}'); do
  env -C "$dir" cargo build
done

echo === 2 ===
rm -rf ~/.rustup ~/.cargo
rustup toolchain install
fd Cargo.toml -x env -C '{//}' cargo build

echo === 3 ===
rm -rf ~/.rustup ~/.cargo
fd Cargo.toml -x env -C '{//}' cargo build

echo === 4 ===
echo DONE

Only third have

... could not rename 'downloaded' file from ...

[rami3l]

@loynoir Thanks. In that case this is indeed a duplicate of #988.

Even though it is not trivial and might require some redesign to address, I'm slowly working on a solution. Please stay tuned...