Cargo build hangs with " Blocking waiting for file lock on the registry index" after building parity from source

Running cargo clean seems to fix the problem.

This happens when you run two compilations of the same project at the same time. The compiler uses a lock file to avoid having data race issues.

There are some possibilities:

• If you ran the two compilations yourself, the solution is obvious: you need to cancel one of them.

• If you use an IDE that automatically compiles your project: you can wait for the job to be finished or close the IDE. If it does not work, this is probably because of RLS hanging out. You can run pkill rls to solve the issue.

• As a last resort, you can force the removal of the lock using rm -rf ~/.cargo/registry/index/* as said in jvatic's answer.

It is important to ensure you have no other rls or cargo running. sudo pkill rls cargo is a good way to ensure they are not.

Removing rm $CARGO_HOME/.package-cache worked for me.

I accidentally hit ctrl+z instead of ctrl+c while executing cargo run and the next execution of cargo run showed me Blocking waiting for file lock on the registry index. I removed the said file and then it worked again.

Edit:
If you accidentally hit ctrl+z like me, you can unsuspend the cargo run process by running fg instead of deleting the package cache file. ctrl+z actually sends a SIGTSTP signal to the process and that process will be suspended until you tell it to continue. See this answer for more info.

I am using this command in macOS Monterey 12.4:

rm -rf ~/.cargo/.package-cache 

then rerun the build command, works.

You usually get this error when you run the cargo build command twice at the same time. If you are using an IDE check if a plugin is running a cargo command in the background, this was the case for me with VS Code.

My issue was the IDE was running cargo and had locked the directory. Try closing your IDE

You can point your IDE to use a different path when building the code. This will prevent conflicts with locks in the future. Add the following compile flags to the IDE:

--target-dir target/rls/ 

In VSCode use the following setting:

"rust-analyzer.runnables.extraArgs": [ "--target-dir", "target/rls/" ] 

My VSCode intellisense was working on a build. Make sure your intellisense is not builing. It displays a little gear icon spinning on bottom. Happens mostly when you update Cargo.toml

I fixed this issue by running the following commands:

1. Search for all rust related processes by $ ps aux | grep rls
2. Stop all of them one by one with $ sudo kill -9 <PID>

Windows: i opened the task manager and end the Cargos processes

Same issue in VScode : if you've installed RLS

1. File | Preferences | Settings
2. Search for "rls"
3. In "rust" extension, uncheck "Start RLS automatically when opening a file or project"

Re-open your project, and it should be solved.

it's work for me on the linux (ubuntu) :

$ rm ~/.cargo/.package-cache 

I had a case where there was an update to my rust extension rust-analyzer in vscode that was causing it. I updated and reloaded the extension and then cargo build ran fine.

This helped to resolve the issue rm ~/.cargo/.package-cache

Blocking started after I added rand = "0.8.5" to my cargo.toml.

Before removing the Cargo registry index as suggested in the accepted answer, make sure no other process is currently compiling Parity or any other Rust package.

I tried to create a Polkadot Node by following the Readme instructions.

I was able to build it by running the following commands (copy/paste into Bash Terminal):

git clone https://github.com/paritytech/polkadot; cd polkadot; git checkout master; rustup update nightly; rustup target add wasm32-unknown-unknown --toolchain nightly; rustup update stable; rustup default stable; cargo install --git https://github.com/alexcrichton/wasm-gc --force; cargo install --git https://github.com/pepyakin/wasm-export-table.git --force; brew install openssl; brew upgrade openssl; rustc --version; cargo --version; ./build.sh; cargo build; cargo run -- --help; ./target/debug/polkadot --help; 

I then tried to run a Polkadot Node with the following commands (which are equivalent):

./target/debug/polkadot -- --chain=dev --validator --key Alice -d /tmp/alice; cargo run -- --chain=dev --validator --key Alice -d /tmp/alice; 

But instead it showed the following:

Blocking waiting for file lock on the git checkouts Blocking waiting for file lock on build directory 

I found it was caused by CLion (Jetbrains IDE).

I solved the problem by closing CLion. I used Visual Studio Code editor instead, which also allows for debugging Rust code with breakpoints

if you ever hit "Blocking waiting for file lock on package cache",

Run the command below and run cargo again. rm $CARGO_HOME/.package-cache

On macOS Sonoma 14.1.1, the way I fixed Blocking waiting for file lock on the registry index when I was trying to run cargo build was to open the Activity Monitor application:

• Press CMD + Space, then type "Activity Monitor.app"
• Click the CPU tab, and enter "cargo" in the search input field at the top right.
• Select all processes with "cargo" in the "Process Name" column
• Click the (X) icon and choose "Force Quit" those processes
• Wait for about a minute or so for those cargo processes to quit
• Re-run your cargo build command without it hanging.

Note: I tried other solutions like quitting VSCode but that wasn't the cause in my situation.

Problem was another process using cargo. I could not find the process to kill so I restarted my local machine and it worked.

What worked for me

For me, I found that the issue was caused by configuring my target dir:

[build] target-dir = ".cargo/target" 

in my .cargo/config.

What didn't work

I ran cargo build --release -vv and saw a message that didn't appear without the -vv flag:

Blocking waiting for file lock on build directory 

I thought this a big clue so I tried stuff like disabling my file backups. I also tried all the answers on this page with no luck.

I think you should use cargo clean and re-run the cargo run command and wait for some time. This usually happens when you try to use a new module in your code by adding it into Cargo.toml file.

On the risk of coming late to the party, while cargo, rls or rust-analyzer are responsible for the lock to avoid data races. An underlying issue maybe the number of inotify filewatchers.

Usually they work fine by spawning a new watcher and wait their turn but if they run out of watchers space this can be a problem. Agreeing to all the above solutions but suggesting to check the number of max_user_watches

# view current settings cat /proc/sys/fs/inotify/max_user_watches # increasing it, /etc/sysctl.conf fs.inotify.max_user_watches=524288 # The new value can then be loaded in by running s $sudo sysctl -p. 

the must fast way is to update your rustc compiler :

rustup update stable 

I was facing a such situation, but then I updated my rustc, the problem has been resolved.