glm-5.1
131e3e929b
Break the @alkdev/taskgraph architecture specs into dependency-ordered implementation tasks across 8 component directories: setup, schema, error, graph, analysis, cost-benefit, frontmatter, api, and review. Each task has clear acceptance criteria referencing specific architecture docs. Three review tasks serve as quality gates at critical junction points (schemas-and-errors, graph-complete, complete-library). The dependency graph is validated acyclic with 9 topological levels enabling significant parallelism across independent work streams.
53 lines
2.6 KiB
Markdown
53 lines
2.6 KiB
Markdown
---
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id: graph/queries
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name: Implement TaskGraph query methods (hasCycles, findCycles, topologicalOrder, dependencies, dependents, taskCount, getTask)
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status: pending
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depends_on:
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- graph/taskgraph-class
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scope: moderate
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risk: medium
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impact: component
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level: implementation
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---
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## Description
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Implement query methods in `src/graph/queries.ts` and integrate on `TaskGraph`. The `findCycles` implementation requires a custom 3-color DFS since `graphology-components` only gives SCCs, not cycle paths.
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Per [errors-validation.md](../../../docs/architecture/errors-validation.md):
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- `hasCycles()` returns boolean (uses `graphology-dag` or `graphology-components` for fast check)
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- `findCycles()` returns `string[][]` — each inner array is an ordered cycle path
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- `topologicalOrder()` throws `CircularDependencyError` with `cycles` populated when graph is cyclic (per ADR-003)
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## Acceptance Criteria
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- [ ] `hasCycles(): boolean` — uses `graphology-dag.hasCycle()` or `graphology-components` SCC check as fast pre-check
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- [ ] `findCycles(): string[][]`:
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- Uses `stronglyConnectedComponents()` as pre-check: if zero multi-node SCCs and no self-loops, skip DFS
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- Custom 3-color DFS (WHITE/GREY/BLACK) to extract cycle paths
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- Returns one representative cycle per back edge, not exhaustive enumeration
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- Each inner array is an ordered node sequence where last node has edge back to first
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- [ ] `topologicalOrder(): string[]`:
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- Uses `graphology-dag.topologicalSort()` for the actual sort
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- **Throws `CircularDependencyError`** (with `cycles` from `findCycles()`) when graph is cyclic
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- Returns `string[]` of task IDs in prerequisite→dependent order
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- [ ] `dependencies(taskId: string): string[]` — returns prerequisite task IDs (inNeighbors). Throws `TaskNotFoundError` if ID doesn't exist.
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- [ ] `dependents(taskId: string): string[]` — returns dependent task IDs (outNeighbors). Throws `TaskNotFoundError` if ID doesn't exist.
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- [ ] `taskCount(): number` — returns number of nodes
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- [ ] `getTask(taskId: string): TaskGraphNodeAttributes | undefined` — returns node attributes or undefined
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- [ ] Unit tests: cycle detection on known cyclic/acyclic graphs, topologicalOrder on DAG, topologicalOrder throws on cyclic graph, dependency/dependent queries
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## References
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- docs/architecture/api-surface.md — query methods
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- docs/architecture/errors-validation.md — cycle handling, CircularDependencyError
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- docs/architecture/cost-benefit.md — findCycles algorithm description
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- docs/architecture/decisions/003-topo-order-throws-on-cycle.md — ADR-003
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## Notes
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> To be filled by implementation agent
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## Summary
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> To be filled on completion |