refactor(match-clause): Complete architecture overhaul - split monoli…

[genezhang]

…thic file into modules

This PR refactors the 4,333-line match_clause.rs monolith into a well-organized module structure:

Module Structure

• traversal.rs (1,159 lines) - Core MATCH pattern traversal and evaluation
• view_scan.rs (899 lines) - ViewScan generation for nodes and relationships
• type_inference.rs (570 lines) - Node label and relationship type inference
• helpers.rs (536 lines) - 14 reusable helper functions
• tests.rs (1,560 lines) - Unit tests
• mod.rs (49 lines) - Public API
• errors.rs (7 lines) - Error types

Key Improvements

• Eliminated 500+ lines of code duplication via helper extraction
• Clear separation of concerns with single-responsibility modules
• Improved testability and maintainability
• Renamed legacy.rs to traversal.rs (final naming)
• Updated method names for graph_catalog compatibility

All 801 tests passing. No functional changes - pure refactoring.

[Copilot]

Pull request overview

This PR successfully refactors the massive 4,333-line match_clause.rs monolith into a well-organized module structure with clear separation of concerns. The refactoring splits the code into 7 focused modules, eliminating significant code duplication and improving maintainability while maintaining all 801 passing tests.

Changes:

• Split monolithic match_clause.rs into 7 specialized modules (traversal, view_scan, type_inference, helpers, tests, errors, mod)
• Eliminated 500+ lines of duplicated code through helper function extraction
• Renamed legacy.rs to traversal.rs for final module naming
• Updated return_clause.rs to use TryFrom instead of From for ProjectionItem conversion

Reviewed changes

Copilot reviewed 9 out of 10 changed files in this pull request and generated 6 comments.

Show a summary per file

File	Description
src/query_planner/logical_plan/match_clause/mod.rs	Public API module with clear re-exports of all functionality
src/query_planner/logical_plan/match_clause/traversal.rs	Core pattern traversal logic (1,159 lines) - handles MATCH evaluation
src/query_planner/logical_plan/match_clause/view_scan.rs	ViewScan generation for nodes and relationships (899 lines)
src/query_planner/logical_plan/match_clause/type_inference.rs	Node label and relationship type inference (570 lines)
src/query_planner/logical_plan/match_clause/helpers.rs	14 reusable utility functions (536 lines)
src/query_planner/logical_plan/match_clause/tests.rs	Comprehensive unit tests (1,560 lines)
src/query_planner/logical_plan/match_clause/errors.rs	Error type re-exports (7 lines)
src/query_planner/logical_plan/return_clause.rs	Updated to use TryFrom with expect for error handling
docs/audits/MATCH_CLAUSE_ARCHITECTURE_PROPOSAL.md	Architecture proposal document (reference material)

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