Task 103: DAG 分析の Rust モデリング

Status: DONE

Motivation

Human directive: DAG は単に並べて可視化するだけでは分かりにくい。解きほぐして表示しないと、どんな依存関係があって、何を変更したら何を直さないといけなくなるのかがわかりにくい。DAG の分析も Rust でモデリングすることで、可視化時に WASM 呼び出しで分析が可能になる。

Scope

1. Rust DAG module (crates/solar-line-core/dag.rs):

- DAG data structure (nodes, edges, types, statuses)

- Topological sort / layered layout algorithm

- Dependency chain extraction (upstream/downstream)

- Impact analysis (invalidation cascade)

- Critical path detection

- Cluster detection (strongly connected components, communities)

- Cycle detection

1. WASM bindings (crates/solar-line-wasm/):

- Expose DAG analysis functions to browser via wasm-bindgen

- Accept JSON DAG state, return analysis results (also JSON)

1. Browser integration (dag-viewer.js):

- Replace current TS-only layout with WASM-powered analysis

- "Untangle" view: show dependency chains clearly, not just flat node layout

- Interactive dependency exploration: click a node → show full upstream/downstream chain highlighted

- Impact visualization: select a node → show cascade of what needs rebuilding

- Better layout that respects dependency flow (left-to-right or top-to-bottom DAG layout)

Dependencies

• Task 085 (DAG foundation — DONE)
• Task 088 (DAG improvements — DONE)

Completed

Phase 1: Rust DAG Module (dag.rs) — 33 tests

• Types: DagNode, Dag, NodeType (5 variants), NodeStatus (3 variants)
• Topological sort (Kahn's algorithm)
• Depth computation (longest path from roots)
• Critical path detection (trace back from deepest node)
• Sugiyama-style layout with barycenter crossing minimization
• Impact analysis with type breakdown
• Subgraph extraction (tag-based with depth expansion)
• Path finding between nodes (DFS with max_paths limit)
• Edge crossing counter (segment intersection)
• Cycle detection (DFS 3-color)
• Orphan detection
• Zero external dependencies maintained

Phase 2: WASM Bindings — 8 tests

• dag_layout: Sugiyama → {ids, x, y, layers, crossings}
• dag_impact: Cascade → {affected, cascade_count, by_type}
• dag_analyze: Full → {topo_order, critical_path, depths, orphans}
• dag_upstream / dag_downstream: Transitive chains
• dag_find_paths: All paths between two nodes
• dag_subgraph: Tag-based extraction

Phase 3: DAG Viewer Enhancement

• WASM integration with JS fallback
• Depth-based Sugiyama layout replaces type-based layout
• Impact / upstream / downstream analysis buttons on node click
• Analysis panel with color-coded affected node badges
• Critical path marking in tooltip
• Edge crossing count display
• Engine badge (WASM/JS indicator)

Notes

• Cluster detection (communities/SCC) deferred — current DAG is acyclic by design
• Keep zero-dependency policy in solar-line-core