Research: in-repo DAG validation and wave-orchestration analogues

[cursor]

Part of #300

Question

Which already-shipped DesignPatterns surfaces are the best analogues for Fork–Join Work Graph MVP Spec writing — specifically for (1) compile-time DAG / cycle / orphan validation and (2) runtime wave or parallel orchestration patterns?

Constraints: facts and options only; do not lock Spec API or severities. Primary sources: this repo (docs/design/, ADRs, generators/diagnostics for State hierarchy, Composite schema/cycles, Composite parallel traversal) plus prior notes on research/concurrency-candidates and research/compile-time-synergy-passers.

Output: research note on a research/<name> branch under docs/.Local/research/; link from this issue.

[Skymly]

Resolved: research note on branch research/work-graph-dag-analogues; see resolution comment.

[Skymly]

Resolution

Research note (local branch research/work-graph-dag-analogues):

docs/.Local/research/work-graph-dag-and-wave-analogues.md

Absolute path: C:\Code\Skymly\DesignPatterns\DesignPatterns\docs\.Local\research\work-graph-dag-and-wave-analogues.md

(Force-tracked on that branch despite .Local/ gitignore; not pushed. Commit d84ff6d.)

(1) Compile-time DAG / cycle / orphan analogues

• Composite parent-key catalog: DP011 unknown parent, DP012 cycle; schema DP063–DP065 (ADR-007) — tree/forest, not general DAG.
• State hierarchy [StateParent]: DP056–DP059 (ADR-005 / StateTransitionValidator) — hierarchy tree + "orphan parent" vocabulary (Info).
• Step Builder After/Before: DP082 cycle / DP084 unknown ref — best multi-predecessor constraint-graph precedent for DependsOn-like edges.
• Prior notes research/concurrency-candidates and research/compile-time-synergy-passers were not found.

(2) Runtime wave / parallel orchestration analogues

• Sole strong shipped precedent: Composite parallel traversal (ADR-006) — especially BFS same-level parallel (BreadthFirstParallel); plus DFS child-parallel, MaxDegreeOfParallelism, MaxParallelDepth, AggregateException.
• Not wave precedents: Chain / Command pipelines, IStateHierarchy, Step Builder (no parallel runner).

Facts/options only — no Spec API or severity locks.