Get Move source code from module published on chain

[banool]

Originally from Stack Overflow.

I have an address with some deployed modules, is there a way for me to get the source code so it will be human readable?

[banool]

When you publish a Move module by default the CLI will include the source code as well as the bytecode. Authors do have the option to opt out of this behavior however. So there are two approaches:

Source available on chain

By default, the source for a Move module is included when it is published on chain. If that is the case, you can download it like this:

aptos move download --account 0x1 --package MoveStdlib

Source not available on chain

Aptos Labs + Verichains recently released a decompiler for this purpose. The source code won't be an exact match syntactically of the original code, but it should be semantically identical.

# Install Revela. The CLI needs this separate tool to decompile the bytecode.
aptos update revela

# Download the package from on chain, in this case MoveStdlib.
aptos move download --account 0x1 --bytecode --package MoveStdlib

# Decompile!
aptos move decompile --package-path MoveStdlib/bytecode_modules

The output should be in MoveStdlib/bytecode_modules. Look for files with the .mv.move extension.

Learn more here: https://aptoslabs.medium.com/move-revealed-the-revela-decompiler-b206eaf48b45.