Hydra + OmegaConf for VS Code

A VS Code extension providing rich language support for Hydra config files and OmegaConf interpolation syntax.

Features

YAML Syntax Highlighting

Enhanced YAML highlighting for Hydra-specific constructs:

• OmegaConf interpolations: ${foo.bar}, ${oc.env:HOME}, nested ${${dynamic}}
• Hydra special keys: _target_, _recursive_, _convert_, _partial_, _args_
• Package directives: # @package _global_
• Defaults list: defaults: block with optional, override, _self_, package @ targets
• Missing values: ??? highlighted as mandatory markers
• Built-in resolvers: oc.env, oc.decode, oc.select, now, hydra, python_version, etc.
• Escaped interpolations: \${not.interpolated}

Goto Definition

Jump to config file definitions from:

• Defaults list entries: - db: mysql → opens conf/db/mysql.yaml
• _target_ values: _target_: my_app.Trainer → opens the Python source file
• Interpolation paths: ${db.host} → jumps to where host is defined

Hover Information

Hover over elements to see:

• Interpolation values: Shows the resolved value of ${...} references
• Resolver documentation: Built-in docs for oc.env, oc.select, now, etc.
• Special key docs: Explains _target_, _recursive_, etc.
• ??? markers: Explains the OmegaConf MISSING value concept
• @package directives: Documentation for package placement

Diagnostics

Real-time error and warning highlighting:

• Unclosed interpolations: Missing } in ${...} expressions
• Unresolvable references: Interpolation paths that can't be found in indexed configs
• Unknown resolvers: Hints when a resolver is not a known built-in
• Missing value markers: Warnings for ??? values that need to be set

Configuration

Setting	Default	Description
hydra.configSearchPaths	["conf", "config", "configs"]	Directories to search for Hydra config files
hydra.enableDiagnostics	true	Enable lint diagnostics for OmegaConf errors
hydra.enableHover	true	Enable hover information for interpolations

Development

# Install dependencies
npm install

# Compile
npm run compile

# Run unit tests
npm run test:unit

# Lint
npm run lint

# Package extension
npm run package

Testing

The extension has comprehensive tests covering:

• Interpolation parser: 25+ tests for ${...} parsing, nested interpolations, resolvers, edge cases
• YAML parser: 25+ tests for flattening, key path extraction, defaults list parsing
• TextMate grammar: 18+ structural tests validating completeness of all grammar patterns
• Test fixtures: Complete Hydra config workspace with realistic configs

License

Apache 2.0