Feature/overrides

[leaanthony]

Overview

This PR introduces a new overrides keyword that allows Taskfiles to override tasks from other Taskfiles, providing a more flexible way to customize and extend task definitions. I have taken what was done in the includes directive and mapped it to overrides.

Key Features

• Task replacement: Unlike includes which errors on duplicate task names, overrides replaces existing tasks with the overridden version
• Automatic flattening: Overridden tasks are automatically available in the local namespace without prefixes
• Nested overrides: Support for multi-level override chains with proper precedence
• Full feature parity: Supports all include options (optional, internal, vars, dir, excludes, aliases)

Implementation Details

New Files

• taskfile/ast/override.go - Core override functionality and AST node definition
• testdata/overrides/ - Comprehensive test cases for override functionality
• testdata/overrides_cycle/ - Cycle detection tests
• testdata/overrides_flatten/ - Flattening behavior tests
• testdata/overrides_interpolation/ - Variable interpolation tests
• testdata/overrides_nested/ - Nested override tests
• testdata/overrides_optional/ - Optional override tests
• testdata/overrides_with_includes/ - Combined includes/overrides tests
• testdata/overrides_with_vars/ - Variable override tests

Modified Files

• taskfile/ast/taskfile.go - Added Overrides field to Taskfile struct
• taskfile/reader.go - Override processing logic with cycle detection
• task_test.go - Comprehensive test coverage for all override scenarios
• website/docs/usage.mdx - Documentation for the new feature
• Various schema and parsing files for YAML/JSON support

Usage Example

  version: '3'

  overrides:
    lib:
      taskfile: ./overrides.yml

  tasks:
    greet:
      cmds:
        - echo "Original"

If ./overrides.yml contains a greet task, it will replace the original version.

Testing

• Added extensive test coverage including:
  • Basic override functionality
  • Cycle detection and prevention
  • Nested overrides with proper precedence
  • Variable interpolation in overrides
  • Integration with existing includes
  • Optional and internal override modes
  • Task exclusion from overrides

Documentation

• Added comprehensive documentation in website/docs/usage.mdx covering:
  • Basic usage and syntax
  • Key differences from includes
  • All configuration options
  • Integration patterns with existing features
  • Multiple examples with tabbed code blocks

Backwards Compatibility

• Fully backwards compatible - existing Taskfiles continue to work unchanged
• The overrides keyword is optional and only processed when present
• Works alongside existing includes functionality

[trulede]

Could you use the existing ´imports´ schema with flatten, and then adjust the behaviour which currently results in the error "If multiple tasks have the same name, an error will be thrown:"?

version: '3'
includes:
  lib:
    taskfile: ./Included.yml
    override: true  # flatten is implicit with this option, perhaps.

[leaanthony]

Could you use the existing ´imports´ schema with flatten, and then adjust the behaviour which currently results in the error "If multiple tasks have the same name, an error will be thrown:"?

version: '3'
includes:
  lib:
    taskfile: ./Included.yml
    override: true  # flatten is implicit with this option, perhaps.

That was my original idea but @andreynering suggested creating a separate key. I may have misinterpreted the request, which is fine, we can adjust.