Feature/v0.0.4 phase1 prep

[dev-parkins]

PR Description: Phase 2 Complete + Signal Support + Coverage Improvements

Branch: feature/v0.0.4-phase1-prep → develop
Version: v0.0.4-dev
Commits: 11 commits
Tests: 405 passing (+15 new)

---

🎯 Overview

This PR completes Phase 2 of v0.0.4 by implementing Godot lifecycle callbacks, signal support, and comprehensive test coverage improvements. All quality gates passing with 0 warnings.

Key Achievements

✅ Signal System: Full signal declaration, registration, and emission support
✅ Phase 2 Lifecycle: All 4 callbacks (_input, _physics_process, _enter_tree, _exit_tree)
✅ Test Coverage: +15 new unit tests (405 total, all passing)
✅ Documentation: Signal visibility research (850+ lines) + coverage justification
✅ Quality: 0 clippy warnings, 0 test failures, all markdown validated

---

📦 Commits Breakdown (11 commits)

🔔 Signal Support (3 commits)

1. d3d05ff - feat(parser): add signal declaration parsing

   • Added signal declaration syntax to parser
   • Foundation for signal system in FerrisScript

2. 466c83a - feat: Add complete signal support for FerrisScript v0.0.4

   • Implemented signal registration in runtime
   • Added emit() functionality for signal emission
   • Integrated with Godot's signal system

3. c69bd95 - feat(signal): enhance documentation for dynamic signal registration

   • Comprehensive signal usage documentation
   • Examples of signal declaration and emission
   • Best practices for signal naming

🔄 Phase 2 Lifecycle Callbacks (4 commits)

4. 70f26be - Merge branch 'develop' into feature/v0.0.4-phase1-prep

   • Sync with latest develop changes
   • Prepare for Phase 2 implementation

5. b437fc4 - feat(phase2.1): Add InputEvent type and _input() callback infrastructure

   • Created InputEvent type system
   • Added _input() lifecycle callback support
   • Foundation for user input handling

6. dcc12d6 - feat(phase2.1): Add _input() lifecycle function validation and tests

   • Type checking for _input(event: InputEvent) signature
   • Error code E305 for invalid lifecycle signatures
   • Comprehensive validation tests

7. 557024c - feat(phase2.2-2.3): Add _physics_process, _enter_tree, _exit_tree callbacks

   • Implemented _physics_process(delta: f32) for physics updates
   • Added _enter_tree() for scene tree entry
   • Added _exit_tree() for cleanup on removal
   • All callbacks fully integrated with Godot lifecycle

8. 6f8b72d - docs(phase2): Complete Phase 2 callbacks + signal visibility architecture research

   • PHASE_2_COMPLETION_REPORT.md (850+ lines)
   • Signal visibility architecture research (V1-V4 approaches)
   • Trade-off analysis for implementation decisions
   • Comprehensive testing documentation

🧪 Testing & Coverage (2 commits)

9. 99492fb - test(phase2): Add comprehensive lifecycle callback tests

   • Validation tests for all 4 lifecycle functions
   • Edge case coverage (multiple callbacks, complex bodies)
   • Error message validation tests

10. 5cc60de - test: Improve test coverage for Phase 2 lifecycle functions

    • +9 compiler tests: E305 validation, combination scenarios
    • +6 runtime tests: InputEvent API, lifecycle execution
    • Total: 405 tests (240 compiler + 74 runtime + 91 integration)

📚 Documentation & Quality (2 commits)

11. d83e88f - docs: Fix markdown linting issues in GODOT_BIND_COVERAGE.md
    • Created GODOT_BIND_COVERAGE.md
    • Explained why godot_bind has 0% unit test coverage
    • Justified integration testing approach
    • Fixed all markdown linting issues

---

✨ Features Added

1. Signal System

Syntax:

signal health_changed
signal position_updated

fn take_damage(amount: f32) {
    emit("health_changed", health - amount);
}

Implementation:

• Parser support for signal keyword
• Runtime registration with Godot
• Dynamic signal emission via emit(signal_name, value)

2. Lifecycle Callbacks

_input(event: InputEvent)

fn _input(event: InputEvent) {
    if event.is_action_pressed("ui_accept") {
        print("Action pressed!");
    }
}

_physics_process(delta: f32)

fn _physics_process(delta: f32) {
    let speed: f32 = 100.0;
    let movement: f32 = speed * delta;
    move_player(movement);
}

_enter_tree() and _exit_tree()

fn _enter_tree() {
    print("Node added to scene tree");
    initialize_resources();
}

fn _exit_tree() {
    print("Node removed from scene tree");
    cleanup_resources();
}

3. InputEvent Type System

API:

• is_action_pressed(action: str) -> bool
• is_action_released(action: str) -> bool
• Runtime validation of input action names

---

🧪 Testing Summary

Test Count Changes

Category	Before	After	Change
Compiler	231	240	+9 ✨
Runtime	68	74	+6 ✨
Integration	91	91	-
Total	396	405	+15 🎉

New Test Coverage

Compiler Tests (+9):

1. test_all_semantic_errors - E301-E305 error code coverage
2. test_input_function_error_code_e305 - _input signature validation
3. test_physics_process_function_error_code_e305 - _physics_process validation
4. test_enter_tree_function_error_code_e305 - _enter_tree validation
5. test_exit_tree_function_error_code_e305 - _exit_tree validation
6. test_multiple_lifecycle_functions - All 4 callbacks coexisting
7. test_lifecycle_function_with_body - Complex function bodies
8. test_input_function_no_param_error_message - Specific error messages
9. test_physics_process_no_param_error_message - Parameter validation

Runtime Tests (+6):

1. test_input_event_is_action_pressed - InputEvent API validation
2. test_input_event_is_action_released - Action release detection
3. test_input_function_with_event_parameter - _input execution
4. test_lifecycle_functions_with_return_values - Return value handling
5. test_lifecycle_functions_with_variables - Local variable scope
6. test_call_function_wrong_arg_count - Error handling

Quality Metrics

✅ cargo test --workspace: 405 passing, 0 failures
✅ cargo clippy: 0 warnings
✅ cargo fmt: All formatted
✅ npm run docs:lint: All passing
✅ npm run docs:links: All valid

---

📚 Documentation Added

1. PHASE_2_COMPLETION_REPORT.md (850+ lines)

Contents:

• Complete Phase 2 implementation details
• Signal visibility architecture research
• 4 implementation approaches (V1-V4) with trade-offs
• Testing strategy and results
• Future roadmap considerations

Key Sections:

• Lifecycle callback implementation
• InputEvent type system design
• Signal registration architecture
• Godot integration patterns

2. GODOT_BIND_COVERAGE.md

Purpose: Explains why crates/godot_bind has 0% unit test coverage

Key Points:

• Integration code requires running Godot engine
• Cannot be unit tested in isolation (needs GDExtension API)
• Tested via godot_test project with manual validation
• Future automation: headless Godot testing, mock API layer

Impact: Justifies coverage exclusion from metrics

---

🔄 Breaking Changes

None - All changes are additive and backward compatible.

Compatibility

• ✅ Existing FerrisScript code continues to work
• ✅ Signal declarations are optional
• ✅ Lifecycle callbacks are opt-in
• ✅ No changes to existing syntax or semantics

---

🎯 Migration Guide

No migration needed - This is a feature addition release.

For New Features

To use signals:

signal my_signal
emit("my_signal", value);

To use lifecycle callbacks:

fn _input(event: InputEvent) { /* handle input */ }
fn _physics_process(delta: f32) { /* update physics */ }
fn _enter_tree() { /* initialize */ }
fn _exit_tree() { /* cleanup */ }

---

📊 Code Coverage Analysis

Patch Coverage: 48.83%

Breakdown:

• godot_bind/lib.rs: 0.00% (43 lines) - Expected (integration code)
• type_checker.rs: 77.92% (17 missing lines) - Improved with new tests
• runtime/lib.rs: 16.66% (5 missing lines) - Improved with lifecycle tests
• error_code.rs: 66.66% (1 missing line) - Covered by semantic error test

Coverage Justification

godot_bind 0% coverage is expected:

• Integration code that bridges Rust ↔ Godot
• Requires running Godot engine for testing
• Tested via godot_test/ integration tests
• Cannot be unit tested in isolation

Remaining gaps (22 lines):

• Edge cases in type checker (complex type inference)
• Runtime error paths (rare execution branches)
• Future improvement target for v0.0.5

---

✅ Quality Gates

All checks passing:

• ✅ Tests: 405/405 passing (0 failures)
• ✅ Clippy: 0 warnings
• ✅ Format: All code formatted
• ✅ Markdown Lint: All docs validated
• ✅ Link Check: All links valid
• ✅ Build: Release build successful

---

🚀 What's Next (v0.0.4 Phase 3)

After this PR merges, Phase 3 will focus on:

1. Property System: @export annotations for Godot inspector
2. Signal Connections: Connect signals to functions in FerrisScript
3. Node References: Type-safe node path access
4. Performance: Optimize runtime execution

Estimated Timeline: Phase 3 completion by end of current sprint

---

📝 Notes for Reviewers

Key Files to Review

1. crates/compiler/src/type_checker.rs - Lifecycle validation logic
2. crates/runtime/src/lib.rs - InputEvent and callback execution
3. docs/planning/v0.0.4/PHASE_2_COMPLETION_REPORT.md - Architecture decisions
4. docs/planning/v0.0.4/GODOT_BIND_COVERAGE.md - Coverage justification

Testing Instructions

# Run all tests
cargo test --workspace

# Run specific lifecycle tests
cargo test --package ferrisscript_compiler lifecycle
cargo test --package ferrisscript_runtime lifecycle

# Check code quality
cargo clippy
cargo fmt --check

# Validate documentation
npm run docs:check

Integration Testing

# Test in godot_test project
cd godot_test
# Open project.godot in Godot 4.x
# Run test_scene.tscn
# Verify lifecycle callbacks execute correctly

---

🎉 Summary

This PR represents complete Phase 2 implementation for FerrisScript v0.0.4:

• ✅ Signal system fully functional
• ✅ All 4 Godot lifecycle callbacks implemented
• ✅ Comprehensive testing with 405 tests passing
• ✅ Extensive documentation (1000+ lines)
• ✅ All quality gates passing with 0 warnings

Ready to merge into develop for continued v0.0.4 development.

[codecov]

Codecov Report

❌ Patch coverage is 52.71318% with 61 lines in your changes missing coverage. Please review.

Files with missing lines	Patch %	Lines
crates/godot_bind/src/lib.rs	0.00%	43 Missing ⚠️
crates/compiler/src/type_checker.rs	77.92%	17 Missing ⚠️
crates/runtime/src/lib.rs	83.33%	1 Missing ⚠️

📢 Thoughts on this report? Let us know!