test(core): a source check fails on module-scope cross-module identity outside a shared key (AST-110 FR3) by cixzhang · Pull Request #10807 · meta/astryx

cixzhang · 2026-11-09T14:58:26Z

Stack: #10807 → #10817 → #10822 → #10831

User impact

None at runtime. A swizzled component carries its own copy of every Core module it reaches, so a module that keeps cross-module identity in module scope — a Symbol() brand, a let counter, a Map/WeakMap registry — splits into two instances: the package's components and the copy's stop agreeing. Today that ships unnoticed: a swizzled Table ignored the package's useTableRowsVirtualization (#10798), and a swizzled LayerProvider showed no toasts (#10800). This check lists such module-scope sites and fails CI on a new one, so a product team's swizzled component keeps working with the package components beside it.

Problem and solution fit

Why do these bugs ship? The FR7 swizzle proof checks each copy on its own; nothing looks for module-scope identity that a copy duplicates.
Why does that matter? spec:AST-110 FR3 requires a copy and the package to share coordinating state, brands and contexts.

scripts/shared-identity.mjs reads the shipped source of Core, Lab, Charts, RichText and Vega with the TypeScript AST and lists:

a module-local Symbol(...) or unique symbol that keys an exported type, or that an exported function reaches;
module-scope state — a let, or a Map/Set/WeakMap/WeakSet or an object or array literal that changes — that an exported function reaches, directly or through the module's own functions (exports from modifiers, export {…} lists and default exports all count);
a store keyed by Document or Window, whether the key is a type argument or a declaration annotation.

It skips state created through the shared-realm helpers (sharedKey, realmValue, createSharedContext), collections with fixed contents that nothing changes, and read-only-typed constants.

scripts/shared-identity.test.mjs fails on a hit scripts/shared-identity.baseline.json does not list, and on a listed entry the source no longer has. The baseline holds today's 253 hits: 121 open entries each name the fix group that removes them, 73 allowed entries carry a reason (memo caches, per-copy observers, idempotent style insertion, development-warning deduplication, synchronous per-call run state, per-copy motion role tables, Markdown's deliberately unshared trust and claim symbols), and 59 are open under triage. Each fix pull request deletes its group's entries.

Expected behavior and authority

spec:AST-110 FR3 (approved, authority: draft): coordinating state lives in one store per document under a registered key, and "a symbol that identifies objects across modules, such as a brand or a context key, is registered under the same kind of key, so a copy and the package agree on it." This change adds one FR7 sentence and its verification row, and updates the record's known verification gap to name the check: "A source check fails when a module that FR3 covers creates a module-local Symbol, WeakMap or registry instead of a registered shared key."

Evidence

The test's own cases: a module-local Symbol() brand on an exported type is flagged; the same brand under sharedKey with a phantom type member passes; a module-scope registry an exported register* writes is flagged; state an export reaches only through a private helper and an export {…} list is flagged; a WeakMap<Document, …> written as a declaration annotation is flagged; an object literal the module changes is flagged.
On main the check finds exactly the 253 baseline entries; it runs in about 1 s.
Two of the open groups are already fixed in flight (fix(Table): a swizzled Table honors the package's virtualization capability #10798, fix(Layer): a swizzled LayerProvider shows the package's toasts #10800); whichever lands after this deletes its entries.

Scope

A test and its baseline; no shipped code changes.
Public text contains no internal Meta context.

Writing rubric results

R1 narration: none; the FR7 sentence states present behavior.
R2 research: none.
R3 evidence: one verification row added.
R4 rejected alternatives: none added.
R5 change references: none.
R6 open questions: none.

Testing

pnpm exec vitest run --project node scripts/shared-identity.test.mjs
pnpm check:knowledge

vercel · 2026-11-09T14:58:33Z

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astracat-bot · 2026-11-09T14:58:41Z

AI review status for this pull request.

Review status	Updated
❓ Needs maintainer input (for maintainers only)	Nov 10, 2026, 1:53 AM UTC

cixzhang · 2026-11-09T15:03:22Z

/approve-spec d787148

github-actions · 2026-11-09T15:17:49Z

PR Analysis Report

🔎 Preview · `20e1229`

Storybook · Sandbox · built from this PR's head

Package size: no published package changed; no new dependencies.

API changes: none in this pull request

Committed API report behind this build: cli 29 rows, core 36 rows, theme-butter 1 row, theme-y2k 1 row; run pnpm api:report.

Not run on this PR: add ci:run-visual, ci:run-a11y or ci:run-rtl to run them.

_{Generated by PR Enrichment workflow | View full report}

astracat-bot

Requesting changes. The source check is a useful ratchet and its four tests pass, but it promises more than it checks.

The title, the User impact ("makes every such site visible") and the new FR7 sentence in docs/specs/AST-110-swizzle-output/spec.md (lines 148-149) say the check fails on any module-local Symbol, WeakMap or registry in an FR3 module, but the FR3 stores the record itself names pass with no baseline entry, namely the layer stack's entries array (packages/core/src/Layer/layerStack.ts:158), the modal outlet stack outlets (packages/core/src/Layer/modalOutlet.ts:44) and the live regions (packages/core/src/hooks/useAnnounce.ts:181), because arrays and object literals are never candidates and a let or collection counts only behind a register…/get…-style exported function that references it directly: widen the check (arrays and object literals, every exported user, private helpers, export {…} lists, annotated Document keys) and baseline the new hits, or narrow those three claims to what it detects.

Also worth fixing: line 236 of the record still says the other verification rows have no check, though the new FR7 row names this test. Because the record changes either way, the new head needs a fresh /approve-spec.

[Automated review]

cixzhang · 2026-11-09T15:42:46Z

/approve-spec 8cb1050

cixzhang · 2026-11-09T15:51:14Z

/approve-spec 7d52273

cixzhang · 2026-11-09T15:55:55Z

/approve-spec d721ce9

astracat-bot

Requesting changes. The check now catches every store the earlier review named, and its five tests pass, but one store in the announcement channel still slips through.

deferredByScope (packages/core/src/hooks/modalAnnounce.ts:349), a module-local WeakMap in the announcement channel that FR3 names, passes with no baseline entry although the new FR7 sentence (docs/specs/AST-110-swizzle-output/spec.md lines 148-149), the title and the User impact say the check fails on it, because scripts/shared-identity.mjs starts its walk only from exported names and this module hands announceFromScope to useAnnounce at load through installModalRoute({…}) (lines 474-477): also start from the functions a top-level statement names, and add the one new hit to the F5 group.

Two smaller points: collections still decide "changes" with a text regex (scripts/shared-identity.mjs lines 151-156) while literals use isMutated, and the record's gap line (line 236) could name the unverified rows instead of saying they have no check on main.

[Automated review]

astracat-bot · 2026-11-09T16:12:02Z

+| FR7      | `scripts/shared-identity.test.mjs` over the source of the packages swizzle copies from, against its baseline                                                   | A module-local `Symbol()` brand in an FR3 module; the same brand under `sharedKey`; a module-scope registry an exported register function writes                                                                                                                                                                                                                                                                                                 | The module-local brand or registry passes, the `sharedKey` brand fails, or a baseline entry the source no longer has stays listed                                                                                                                                                                                                                                                                                                                           |

-Known verification gap: only FR3's shared-context checks (`sharedContexts.test.tsx`) exist; the other rows have no check on `main`.
+Known verification gap: only FR3's shared-context checks (`sharedContexts.test.tsx`) and FR7's source check (`scripts/shared-identity.test.mjs`) exist; the other rows have no check on `main`.


Non-blocking: "the other rows have no check on main" is temporary status. Name the unverified rows instead, for example: "Known verification gap: FR1, FR2, FR3's store row, FR4, FR5, FR6 and FR7's swizzle-proof row have no check."

cixzhang · 2026-11-09T16:24:32Z

/approve-spec a13fa57

astracat-bot

Approved pending CI: CI has not run this pull request's tests on this head yet, and the deferred test lane runs before merge.

The source check now also follows functions a module hands to another module at load, so deferredByScope in packages/core/src/hooks/modalAnnounce.ts is caught and listed in the baseline, and seeded collections use the same mutation test as literals. The six tests pass, and the baseline matches the source on this head and on main.

Two optional cleanups:

docs/specs/AST-110-swizzle-output/spec.md line 236 still ends "the other rows have no check on main"; naming the unverified rows instead keeps temporary status out of the record.
The description still says 253 hits and 121 grouped entries; the baseline now holds 254 entries, 122 of them in fix groups.

[Automated review]

…y outside a shared key scripts/shared-identity.mjs reads the shipped source of the packages swizzle copies from with the TypeScript AST and lists module-local symbols that key an exported type or that an exported function reads or writes, and module-scope registries an exported register, subscribe, read or identity function uses, or that are keyed by a document or window. scripts/shared-identity.test.mjs fails on a hit the baseline does not list and on a listed entry the source no longer has. The baseline holds today's 79 hits: open entries name their fix group, allowed entries their reason. AST-110 FR7 names the check.

…s own functions

…dule changes

…s out at load

cixzhang · 2026-11-09T16:43:16Z

/approve-spec 20e1229

astracat-bot

This pull request is reviewed as part of its stack; see the review on #10831.

cixzhang requested review from imdreamrunner and josephfarina as code owners November 9, 2026 14:58

meta-cla Bot added the CLA Signed This label is managed by the Meta Open Source bot. label Nov 9, 2026

github-actions Bot added the needs:spec-owner-review Current knowledge records await owner approval label Nov 9, 2026

cixzhang force-pushed the test/fr3-shared-identity-check branch from 8883915 to d787148 Compare November 9, 2026 15:02

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Comment thread docs/specs/AST-110-swizzle-output/spec.md Resolved

Comment thread scripts/shared-identity.mjs Resolved

Comment thread docs/specs/AST-110-swizzle-output/spec.md Resolved

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feat(core): shared-realm helpers hold every kind of cross-module state (AST-110 FR3) #10817

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fix(core): page scroll and selection locks are one per page across Core loads (AST-110 FR3) #10822

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cixzhang added 6 commits November 9, 2026 08:36

test(core): the source check follows every export through the module'…

6e80383

…s own functions

test(core): move highlight registration and theme injection to triage

35a6a97

test(core): the source check counts an object or array literal the mo…

a1ac5b3

…dule changes

test(core): the source check also starts from functions a module hand…

528532e

…s out at load

test(core): drop the toast host entries #10800 fixed

20e1229

cixzhang force-pushed the test/fr3-shared-identity-check branch from a13fa57 to 20e1229 Compare November 9, 2026 16:38

cixzhang mentioned this pull request Nov 9, 2026

fix(core): focus traps and the keyboard model are one per page across swizzled copies (AST-110 FR3) #10831

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cixzhang marked this pull request as draft November 10, 2026 01:33

cixzhang marked this pull request as ready for review November 10, 2026 01:33

cixzhang merged commit 05ff3f5 into main Nov 10, 2026
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cixzhang mentioned this pull request Nov 10, 2026

test(core): the FR3 baseline follows main (fixes main's source check) #10948

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