Skip to main content
Version: dev

Migration notes

Noir is in full-speed development. Things break fast, wild, and often. This page attempts to leave some notes on errors you might encounter when upgrading and how to resolve them until proper patches are built.

backend encountered an error: libc++.so.1​

Depending on your OS, you may encounter the following error when running nargo prove for the first time:

The backend encountered an error: "/home/codespace/.nargo/backends/acvm-backend-barretenberg/backend_binary: error while loading shared libraries: libc++.so.1: cannot open shared object file: No such file or directory\n"

Install the libc++-dev library with:

sudo apt install libc++-dev

≥0.19​

Enforcing compiler_version​

From this version on, the compiler will check for the compiler_version field in Nargo.toml, and will error if it doesn't match the current Nargo version in use.

To update, please make sure this field in Nargo.toml matches the output of nargo --version.

≥0.14​

The index of the for loops is now of type u64 instead of Field. An example refactor would be:

for i in 0..10 {
    let i = i as Field;
}

≥v0.11.0 and Nargo backend​

From this version onwards, Nargo starts managing backends through the nargo backend command. Upgrading to the versions per usual steps might lead to:

backend encountered an error​

This is likely due to the existing locally installed version of proving backend (e.g. barretenberg) is incompatible with the version of Nargo in use.

To fix the issue:

  1. Uninstall the existing backend
nargo backend uninstall acvm-backend-barretenberg

You may replace acvm-backend-barretenberg with the name of your backend listed in nargo backend ls or in ~/.nargo/backends.

  1. Reinstall a compatible version of the proving backend.

If you are using the default barretenberg backend, simply run:

nargo prove

with your Noir program.

This will trigger the download and installation of the latest version of barretenberg compatible with your Nargo in use.

backend encountered an error: illegal instruction​

On certain Intel-based systems, an illegal instruction error may arise due to incompatibility of barretenberg with certain CPU instructions.

To fix the issue:

  1. Uninstall the existing backend
nargo backend uninstall acvm-backend-barretenberg

You may replace acvm-backend-barretenberg with the name of your backend listed in nargo backend ls or in ~/.nargo/backends.

  1. Reinstall a compatible version of the proving backend.

If you are using the default barretenberg backend, simply run:

nargo backend install acvm-backend-barretenberg https://github.com/noir-lang/barretenberg-js-binary/raw/master/run-bb.tar.gz

This downloads and installs a specific bb.js based version of barretenberg binary from GitHub.

The gzipped file is running this bash script, where we need to gzip it as the Nargo currently expect the backend to be zipped up.

Then run:

DESIRED_BINARY_VERSION=0.8.1 nargo info

This overrides the bb native binary with a bb.js node application instead, which should be compatible with most if not all hardware. This does come with the drawback of being generally slower than native binary.

0.8.1 indicates bb.js version 0.8.1, so if you change that it will update to a different version or the default version in the script if none was supplied.