lineguard

LineGuard Implementation Plan (COMPLETED)

Note: This implementation plan has been fully completed. All planned features have been successfully implemented and tested. The project was developed following strict Test-Driven Development (TDD) practices as specified in PRODUCT_SPEC.md.

Implementation Summary

✅ Completed Features:

1. Core Functionality
   • Newline ending check
   • Trailing space detection
   • Parallel file processing
   • Multiple output formats (human, JSON, GitHub Actions)
2. Advanced Features
   • Configuration file support (.lineguardrc)
   • Auto-fix capability with dry-run mode
   • Streaming support for large files (>10MB)
   • Permission error handling
   • CLI flags to disable specific checks
   • Ignore patterns and file extension filtering
   • Progress indicators for large file sets
   • Binary file detection and skipping
3. Developer Experience
   • Comprehensive test coverage
   • Clear documentation
   • Colored output support
   • Intuitive CLI interface
   • Helpful error messages

Original Development Phases

Phase 1: Project Setup and Core Infrastructure ✅

Goal: Establish project foundation and basic structure

Milestone 1.1: Project Initialization ✅

• Initialize Rust project with Cargo
• Set up directory structure
• Configure Cargo.toml with basic dependencies
• Set up Git repository
• Create initial README.md

Milestone 1.2: Development Environment ✅

• Set up Rust formatter (rustfmt.toml)
• Configure Clippy linting rules
• Create Makefile for common tasks
• Set up pre-commit hooks
• Configure GitHub Actions for CI

Milestone 1.3: Core Types and Error Handling ✅

• Define core data structures
• Implement error types with thiserror
• Create result type aliases
• Write unit tests for types

Phase 2: File Discovery and CLI

Goal: Implement file discovery and basic CLI functionality

Milestone 2.1: CLI Argument Parsing

• Test: CLI accepts file paths
• Test: CLI validates arguments
• Test: Help and version display
• Implement CLI module with clap
• Handle argument validation

Milestone 2.2: File Discovery

• Test: Discover single file
• Test: Discover multiple files
• Test: Handle glob patterns
• Test: Recursive directory search
• Implement file discovery module

Milestone 2.3: Configuration Loading

• Test: Load default configuration
• Test: Parse config file
• Test: Merge CLI and file config
• Implement configuration module

Phase 3: Core Checking Logic

Goal: Implement the actual lint checking functionality

Milestone 3.1: Newline Ending Check

• Test: Detect missing newline
• Test: Detect multiple newlines
• Test: Handle empty files
• Implement newline checking logic
• Handle different line endings (LF/CRLF)

Milestone 3.2: Trailing Space Detection

• Test: Detect trailing spaces
• Test: Detect trailing tabs
• Test: Handle mixed whitespace
• Implement trailing space detection
• Track line numbers accurately

Milestone 3.3: File Processing

• Test: Process single file
• Test: Handle binary files
• Test: Handle large files
• Implement file reading with streaming
• Add parallel processing support

Phase 4: Output and Reporting

Goal: Implement various output formats

Milestone 4.1: Human-Readable Output

• Test: Format single issue
• Test: Format multiple issues
• Test: Summary statistics
• Implement human-readable reporter
• Add color support

Milestone 4.2: JSON Output

• Test: Serialize results to JSON
• Test: Handle edge cases
• Implement JSON reporter
• Validate against schema

Milestone 4.3: GitHub Actions Output

• Test: Format for GitHub Actions
• Implement GitHub reporter
• Test in actual GitHub workflow

Phase 5: Advanced Features

Goal: Add configuration and usability features

Milestone 5.1: Ignore Patterns

• Test: Parse gitignore syntax
• Test: Apply ignore patterns
• Implement ignore functionality
• Support custom ignore files

Milestone 5.2: Progress Indication

• Test: Progress bar updates
• Implement progress tracking
• Handle terminal capabilities

Milestone 5.3: Performance Optimization

• Benchmark current performance
• Optimize file reading
• Tune parallel processing
• Add performance tests

Phase 6: Polish and Release

Goal: Prepare for public release

Milestone 6.1: Documentation

• Write comprehensive README
• Create user documentation
• Document API for library usage
• Add code examples

Milestone 6.2: Testing and Quality

• Achieve 90%+ test coverage
• Add integration test suite
• Fuzz testing for edge cases
• Performance regression tests

Milestone 6.3: Release Preparation

• Create release binaries
• Set up automated releases
• Publish to crates.io
• Create homebrew formula

Testing Strategy per Milestone

TDD Cycle for Each Feature

1. Red Phase: Write failing test
   • Define expected behavior
   • Test should be minimal and focused
   • Verify test fails for right reason
2. Green Phase: Make test pass
   • Write minimal implementation
   • Don’t add extra functionality
   • All tests must pass
3. Refactor Phase: Improve code
   • Only after git commit
   • Maintain all passing tests
   • Improve structure and clarity

Test Categories

• Unit Tests: Test individual functions
• Integration Tests: Test module interactions
• CLI Tests: Test command-line interface
• Performance Tests: Ensure speed requirements

Quality Gates

Before Each Commit

• All tests pass (cargo test)
• No Clippy warnings (cargo clippy)
• Code formatted (cargo fmt --all -- --check)
• Builds without warnings (cargo build)

Before Each Milestone

• Test coverage > 85%
• Documentation updated
• Changelog updated
• No TODO comments in code

Before Release

• All milestones complete
• Security audit passed
• Performance benchmarks met
• Cross-platform testing done

Time Estimates

Phase	Duration	Description
Phase 1	1 day	Project setup
Phase 2	3 days	CLI and file discovery
Phase 3	3 days	Core checking logic
Phase 4	2 days	Output formatting
Phase 5	2 days	Advanced features
Phase 6	2 days	Polish and release
Total	13 days	Full implementation

Risk Mitigation

Technical Risks

• Large file handling: Implement streaming early
• Performance issues: Profile and benchmark regularly
• Cross-platform bugs: Test on CI from start

Process Risks

• Scope creep: Stick to MVP features first
• Test coverage: Enforce coverage in CI
• Documentation drift: Update docs with code

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