Data-bound chart components 4/8: serve composite plan tokens

[FarhanAliRaza]

Stacked on #463. Base is stack/3-plans-and-data-vars.

Makes xyp1|<digest>|<data token> a servable figure identity.

Change

The namespace learns one concept — what a token reveals about affinity and rebuildability — instead of branching on prefixes at each call site:

• a composite enforces affinity through its embedded data token and rebuilds like any state token;
• a bare xyd1 token names columns, never a figure, so it keeps affinity but is never served or rebuilt as one.

Serving a composite is plan lookup + columns (registry hit, else the data method re-run against session state) + bind into a fresh Chart. Both halves are independently recoverable on any worker, so §3.2's reconnect promise holds for this tier without a central store.

Failures are typed rather than flattened to "unknown figure token": a plan miss (hot-reload digest drift) answers err {resync} naming the digest, and a bind mismatch answers the reason naming both sides.

The registry's error seam is wired to a room-wide err broadcast here — a column republish whose bind fails has no request to answer, and without this subscribers would sit on stale pixels with nothing in the log.

The wire envelope grew no fields. Rooms, versions, mid addressing, and the attachment cap treat a composite as an ordinary fig string.

Spec

reflex-integration.md §3.6 (composite tokens, republish fan-out), file map.

Test plan

• uv run pytest tests/reflex_adapter tests/test_validation_timing.py — 208 passed, including composite fan-out, plan-miss resync, and bind-error frames against a real uvicorn + socket.io client
• pre-commit run --all-files, ruff check, ruff format --check, ty check — clean

[coderabbitai]

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[greptile-apps]

Greptile Summary

The PR makes composite plan/data tokens servable as figure identities and adds recovery, affinity, fan-out, and typed error handling for that tier.

• Resolves composite figures by combining a registered plan with cached or rebuilt state-backed columns.
• Tracks mounted plan dependencies and prunes them across subscription, release, rebuild, and TTL lifecycle transitions.
• Adds Socket.IO integration coverage for serving, state recovery, affinity, republishing, and error responses.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains.

Important Files Changed

Filename	Overview
python/reflex_xy/namespace.py	Adds composite-token identity, affinity, rebuild dispatch, plan binding after successful resolution, and typed request or room-wide errors.
python/reflex_xy/registry.py	Extends plan-index cleanup across the transitions that end a composite mount.
python/reflex_xy/state_bridge.py	Rebuilds data-backed figures by resolving plans, recovering columns from Reflex state, and binding them into fresh figures.
python/reflex_xy/app.py	Wires registry-side failures to namespace room broadcasts.
spec/design/reflex-integration.md	Documents composite-token serving, recovery, affinity, fan-out, and cleanup semantics.
tests/reflex_adapter/test_data_var.py	Covers plan-index cleanup for unsubscribe, disconnect, release, and TTL sweep transitions.
tests/reflex_adapter/test_socket_data_plane.py	Adds transport-level composite-token tests for serving, interactions, recovery, affinity, fan-out, and typed errors.

_{Reviews (3): Last reviewed commit: "fix(reflex): unbind plan index on every ..." | Re-trigger Greptile}

[codspeed-hq]

Merging this PR will not alter performance

✅ 109 untouched benchmarks
⏩ 2 skipped benchmarks¹

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_{Comparing stack/4-composite-serving (0e39225) with stack/3-plans-and-data-vars (9fd4362)²}

Footnotes

1. 2 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

2. No successful run was found on stack/3-plans-and-data-vars (794dae6) during the generation of this report, so 72b4f87 was used instead as the comparison base. There might be some changes unrelated to this pull request in this report. ↩

[cubic-dev-ai]

All reported issues were addressed across 6 files

<sub>Reply with feedback, questions, or to request a fix.

Fix all with cubic | Re-trigger cubic</sub>

[FarhanAliRaza]

Review addressed in bf312d0 — plan-index lifecycle (P2): _digests_by_data_token is now pruned on every transition that can end a mount — last unsubscribe, disconnect, release, failed-rebuild cleanup, TTL sweep, and the republish-finds-unmounted path — all funneling through _unbind_plan_if_unmounted_locked. A cached figure entry keeps the binding alive (still mounted); dropping the last of entry+subscribers drops it, so short-lived sessions no longer accumulate bindings that only a later republish would have collected. "Bounded by mounted plans" now holds unconditionally; pinned by test_data_var.py::test_unmount_transitions_drop_plan_bindings, spec updated.

[greptile-apps]

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