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glm-5.1 c9c32a6aa6 decompose reconciler roadmap into 20 implementation tasks across 5 phases

Tasks follow the architecture spec phases:
- Phase 0: key field on UElement (2 tasks + review)
- Phase 1: reactive-host bridge / fiber tree (4 tasks + review)
- Phase 2: key-based children reconciliation (3 tasks + review)
- Phase 3: unmount & dispose support (4 tasks)
- Phase 4: TypeBox value optimizations (4 tasks)

Validated with taskgraph CLI: no cycles, 15 parallel generations,
3 high-risk tasks identified (signal-driven-updates, commit-mutations,
fiber-disposal).

2026-05-18 16:26:52 +00:00

2.2 KiB

Raw Blame History

id, name, status, depends_on, created, modified, scope, risk, impact, level

name

status

depends_on

created

modified

scope

risk

impact

level

key-matching-algorithm

Key-based old↔new child matching

pending

review-reactive-host-bridge

2026-05-18T16:22:57.216123897Z

2026-05-18T16:22:57.216124341Z

narrow

medium

component

implementation

Description

Implement the key-based matching algorithm that maps old children to new children by key field. When the tree structure changes (children added, removed, reordered), positional matching is insufficient — it would destroy and recreate instances instead of moving them.

This algorithm builds two maps from the old and new child lists:

oldKeyMap: Map<key | null, Fiber> — old children keyed by their key field (positional fallback for null keys)
New children are classified as: matched (key exists in old), added (new key), removed (old key not in new)

For matched children:

Same type: will reconcile props (same as Step 2)
Type changed: remove old + insert new

Unkeyed children (key = undefined) fall back to positional matching.

Acceptance Criteria

reconcileChildren function implemented in src/host/reconcile.ts
Builds oldKeyMap from existing fiber children
Classifies new children into matched, added, removed sets
Matched children with same type → flag for prop reconciliation
Matched children with different type → old removed, new inserted
Unkeyed children (key = undefined) use positional matching fallback
Duplicate keys: warn and use last-wins (per ADR-004 consequences)
Pure function — no side effects, returns classification for downstream use
New test: keyed children reordered → matched correctly by key
New test: keyed child added at start → old children matched, new child added
New test: keyed child removed → classified as removed
New test: mixed keyed and unkeyed children → key-based for keyed, positional for unkeyed
New test: duplicate key → last-wins, no crash

References

docs/architecture/reconciler.md — Step 3 (Reconcile Children, Key-Based)
docs/architecture/decisions/004-key-as-first-class-field.md — ADR-004, duplicate key behavior

Notes

To be filled by implementation agent

Summary

To be filled on completion

2.2 KiB Raw Blame History