Fixup Usage

This note covers the Compact fixup tool, which automatically migrates your code when the language changes.

Docs: Fixup Usage

Intuition First

The fixup tool exists because Compact evolves. When the language adds new syntax or changes existing behavior, old code may not compile.

Fixup reads your source file, applies automatic migrations for known language changes, writes the updated code. It’s like a linter that fixes things for you.

Fixup doesn’t make arbitrary changes. It only applies known transformations from documented language changes.

Installation

Fixup comes with the Compact toolchain:

fixup-compact --version

Basic Usage

Fixup to Standard Output

fixup-compact contracts/contract.compact

Prints the updated code to stdout.

Fixup to a File

fixup-compact contracts/contract.compact fixed/contract.compact

Writes to the specified output file.

Fixup In-Place

fixup-compact contracts/contract.compact contracts/contract.compact

Overwrites the original.

Warning: Always output to a different file first and review the changes. Fixup can introduce errors if the transformation doesn’t apply to your code.

Command-Line Flags

Update Uint Ranges

fixup-compact --update-Uint-ranges contracts/contract.compact

This transforms Uint<0..n> declarations where n is a constant.

Compact Search Path

fixup-compact --compact-path /path/to/modules contracts/contract.compact

Sets directories where the fixup tool searches for imported modules.

Via the Compact CLI

The main compact CLI invokes fixup:

compact fixup contracts/           # fixup all .compact files in directory

Reviewing Changes

Always review before committing:

# 1. Fixup to a new file
fixup-compact contracts/contract.compact fixed/contract.compact

# 2. Compare
diff contracts/contract.compact fixed/contract.compact

# 3. If OK, replace
mv fixed/contract.compact contracts/contract.compact

# 4. Recompile
compact compile contracts/contract.compact contracts/managed/contract

Never run fixup and commit without reviewing.

Error Handling

If the source file has errors that fixup can’t handle:

$ fixup-compact contracts/broken.compact
Exception: /path/contracts/broken.compact line 12 char 5:
  type error: expected Uint<64>, got Field

Fixup reports static errors and exits without producing output.

Before Upgrading the Toolchain

# 1. Update compact
compact update

# 2. Run fixup on your codebase
compact fixup contracts/

# 3. Recompile
compact compile contracts/contract.compact contracts/managed/contract

# 4. Run tests
npm test

Quick Recap

• Fixup automatically migrates code for language changes.
• Always review changes before committing.
• Recompile and test after applying fixup.
• Fixup doesn’t fix logic errors, only deprecated syntax.

Cross-Links

• Previous: Formatter Usage Code formatting
• Next: Neovim Setup Editor integration
• See also: Testing and Debugging Error handling