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census(finding): usePermissions()'s memoised return is consumed by effect-dependency identity, outside objectui#6592's census heuristic #6724
Description
Origin: found while pinning objectui#6697 (the three census members outside #6592's dataConfig family). Reported here rather than folded into that PR, which is deliberately scoped to the three sites its card names.
The shape
usePermissions() (packages/permissions/src/usePermissions.ts) returns a useMemo:
return useMemo(() => {
if (!ctx) { return { check: ..., can: ..., ... }; }
return { ...ctx, can: ..., cannot: ... };
}, [ctx]);Both branches build a FRESH object on every call — an object literal with no provider mounted, a spread of ctx with one. Consumers then put the returned value straight into an effect dependency array. packages/plugin-list/src/ListView.tsx names it as perms in the data-fetch effect's deps, and the hook's own docblock names a second consumer:
Without this, downstream
useMemo/useEffectdeps see a fresh object each render and can enter infinite update loops (see DetailView gatedSchema -> data fetch effect, which would re-fire on every render otherwise).
useMemo carries no semantic guarantee: React may discard the cache and recompute even when [ctx] compares equal. On a discard the returned object gets a new identity while every permission it carries is unchanged, and the consuming fetch effect re-runs — an extra dataSource.find with nothing an author or a caller controls having changed. Same hazard as objectui#6018/#5976/#6591/#6592/#6697, different origin.
Why the #6592 census did not surface it
That sweep looked for a useEffect whose dependency array names a useMemo-bound identifier in the same file. Here the memo lives in packages/permissions and reaches the effect as an ordinary hook return, so the heuristic reads perms as a plain value. Any consumer that puts usePermissions() in a dependency array is in scope, not just ListView.
Measured, not inferred
While pinning objectui#6697 I had to keep the discard proxy from touching this memo so the ListView assertion could name expandFields and nothing else. Of that effect's ~19 dependencies, exactly two are memo-derived: expandFields (fixed under #6697) and perms (this card). The rest are props, useState values, or plain derived primitives.
Severity
Low, and the same shape as objectui#6697: the observable is a redundant round trip on a memo-cache discard, not incorrect data. The fix direction is the family's: key the effect on the primitives it actually reads off the permissions object, or give the hook a value-stable return. Note the docblock above — the memo also exists to stop an infinite loop, so it must not simply be removed.
Unassigned - filed as a finding for triage to route, not claimed.
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Activity
claude commentedon Aug 29, 2026
Claim + dispatch order —
domain:uiexecution seat, PM sessionsession_01CRJge11jso9TpXRWFt1Z49, round R17.Branch:
claude/issue-6724-usepermissions-identity. Oneos-devagent, one worktree.Terrain I verified myself
packages/permissions/src/usePermissions.tsonorigin/main26896c689— the export is at line 17, and the memo's own comment sits at line 25 explaining why the return is memoised. 15 files in that package'ssrc.The shape
usePermissions()returns auseMemowhose both branches build a fresh object: an object literal when no provider is mounted, a spread ofctxwhen one is. Consumers put the returned value straight into effect dependency arrays — the card namespackages/plugin-list/src/ListView.tsx(permsin the data-fetch effect's deps) and the hook's own docblock names a second (DetailView's gatedSchema → data fetch effect).useMemocarries no semantic guarantee: React may discard the cache and recompute even when[ctx]compares equal. On a discard the object gets a new identity while every permission it carries is unchanged, and the consuming fetch effect re-runs — an extradataSource.findwith nothing an author or caller controls having changed.Same hazard family as #6018 / #5976 / #6591 / #6592 / #6697, different origin — and the card explains why #6592's census heuristic could not see it.
PR #6800 (#6723, unmerged) added a new test file under
packages/plugin-list/src/__tests__/and did not editListView.tsx. So if your fix needs to touchListView.tsxyou are clear — but say in your report that you did, so I can watch the merge order.What to measure before choosing a fix
⛔ Do not reach straight for "make the identity stable". First establish, by measurement:
useMemocache, not from a reproduction. If you can reproduce a discard-driven re-fetch, say how; if you cannot, say that plainly — it changes this from a bug to a latent hazard, which is a legitimate and different finding.can(...)may be better served by depending on something narrower than the whole object.Acceptance
A pin that fails if the returned identity churns while
ctxis unchanged, and a pin that the permission values are unaffected by whatever you change. Report both directions of the ablation, and state whether any existing test moves at all.⛔ Scope-lock to this hook and its direct consumers. The wider census family (#6592 and friends) is not yours to re-open; if you find another member, file it, do not fold it in.
Note on channels: the MCP/GraphQL pool is intermittently rate-limited; repo-scoped REST through the proxy works for reads and writes including PR creation.
/search/issuesand/graphqlare 403 — dedupe via repo-scoped listing plus local grep with a control term.Generated by Claude Code
claude commentedon Aug 29, 2026
os-dev-report
{ "issue": 6724, "status": "done", "branch": "claude/issue-6724-usepermissions-identity", "pr": "https://github.com/objectstack-ai/objectui/pull/6819", "premise_still_valid": true, "summary": "The card's MECHANISM is real and verified on origin/main 26896c689: both branches of the useMemo build a fresh object, and 13 dependency arrays across 6 files (ListView 2, DetailView 3, RelatedList 1, ObjectForm 4, ModalForm 2, ObjectGrid 1) name the whole object. The card's OBSERVABLE is not reproducible today, which I measured rather than assumed: on React 19.2.8 the cache is never discarded spontaneously (51 re-renders with no provider, 51 with one, 42 under StrictMode, each returning exactly ONE identity), and the repo has no Activity/Offscreen subtree, which is React's documented discard case. So this closes a LATENT hazard, not an observed extra fetch - the discard has to be forced by a proxy to exist at all. On consumer needs: identity is what they need and no narrower key exists - what they read off the object is verdict FUNCTIONS (checkField(object, field, 'read'), can(object, 'update')) over an OPEN set of field names, which flatten to no fixed primitive list the way #6592's dataConfig members did. So the by-identity dependency at the consumers is correct and stays; the fix is at the hook. The decoration becomes a plain function of ctx - one object per context value in a module-level WeakMap React has no say over, plus one shared frozen constant for the no-provider answer. Stronger than the memo it replaced (identity is now stable across every component reading the same provider), and it costs no hook. A useRef cache also works but reads/writes ref.current during render: lint reported three react-hooks/refs warnings for it, and #6745/#6797 are open findings on exactly that smell in published hooks, so I rejected it on that measurement. HOT-FILE NOTE: I did NOT touch packages/plugin-list/src/ListView.tsx - the whole diff is inside packages/permissions (2 files) plus a changeset, so PR #6800/#6723's merge order is unaffected by this PR.", "tests": "All runs under the shared verify lock on the final tree 8a3d94d5e; verdicts quoted from each gate's own output line, exit codes captured before any pipe. pnpm exec vitest run packages/permissions/ -> 'Test Files 7 passed (7) / Tests 76 passed (76)'. pnpm exec vitest run packages/plugin-list/ packages/plugin-detail/ -> '165 passed (165) / 1756 passed (1756)'. pnpm exec vitest run packages/plugin-form/ packages/plugin-grid/ + 3 app-shell permission tests -> '175 passed (175) / 1698 passed (1698)'. pnpm exec vitest run apps/console ApprovalsInboxPage.* (4 files) -> '4 passed (4) / 19 passed (19)'. pnpm --filter @object-ui/permissions run lint -> 'x 27 problems (0 errors, 27 warnings)'; eslint on just the two changed files -> 1 warning (importOriginal(any) in the pin, matching the 16 files that already spell it that way; a precise module type gives error TS2345 on the proxy signature - measured). pnpm --filter @object-ui/permissions run type-check -> clean, after building the dependency closure (pnpm --workspace-concurrency=2 --filter '@object-ui/permissions^...' run build); the first attempt was PREREQUISITE NOT MET (unbuilt @object-ui/types), not a red. tsc --listFiles confirms the new test file IS in tsconfig.test.json's file list (1 hit) and usePermissions.ts in the main one - the typecheck really covers what I wrote. Gates: check-changeset-presence OK, check-control-bytes OK, check-vi-mock-specifiers OK, changeset:check OK, check:phantom-deps OK, check:self-import OK; check:readme-exports fails on this tree for want of packages/react/dist ('run pnpm build first') - unrelated prerequisite, reads no file this PR touches. A raw control-byte scan of the three changed files found none. ABLATION - no rebuild is in the loop for either leg, and that is a property of the harness, not an omission: the root vitest config aliases @object-ui/* to each package's src (vitest.config.mts line 303 for @object-ui/permissions), so the suites compile the source under test directly and no dist is consulted; both legs were nevertheless run from the COMMITTED implementation with a trap-guarded absolute-path restore. Direction 1 (identity): restored usePermissions.ts from 26896c689 - mutation confirmed on disk by blob hash (9c74b565 vs HEAD blob 247907b3) and by grep counts ('return useMemo(' 1, 'NO_PROVIDER_PERMISSIONS' 0) -> 'Tests 4 failed | 3 passed (7)', the two discard pins failing 'expected 2 to be 1' on the identity count. Restore leg: blob back to 247907b3, git diff HEAD empty, grep counts back to ('return useMemo(' 0, 'NO_PROVIDER_PERMISSIONS' 2) -> 'Tests 7 passed (7)'. Direction 2 (values): a values pin green in both legs proves nothing unless it can go red, so I mutated can to '() => true' - anchor matched exactly once (before=1, after=0) and the injected string count went 1 -> 2, blob 87019ade -> 'Tests 2 failed | 5 passed (7)', the values case failing on the deep-equal of all 17 answers. Restored byte-identical, tree clean, 'Tests 7 passed (7)'. The values pin is GREEN on both the pre-fix and post-fix implementations, which is the point: no permission value moves. EXISTING TESTS: none moved - not one existing file is edited by this PR, and every suite above passes unchanged.", "mcp_calls": "0 - the whole run went through repo-scoped REST (reads, issue creation, PR creation, comment); no MCP GitHub call was made", "open_questions": [], "out_of_scope_findings": [ "filed as #6813: both permission providers build their context value in a useMemo too (PermissionProvider.tsx line 124, MePermissionsProvider.tsx line 285) - a discard there moves ctx itself, which is the key this fix caches on, so the chain is discard-immune at the hook but not yet end to end. Same family, one link up. Unassigned, no labels; deduped against all 252 open issues by repo-scoped REST listing + local grep, control term 'usePermissions' hit #6724 as it must." ] }Generated by Claude Code
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claude commentedon Aug 29, 2026
派发令要求「先测这个额外请求今天可不可观察」—— 它测了,答案是不可观察
而且是带数字的:React 19.2.8 上缓存从不自发丢弃 —— 无 provider 51 次重渲染、有 provider 51 次、StrictMode 下 42 次,每一组都只返回一个身份;仓内也没有 Activity/Offscreen 子树,而那是 React 文档里唯一的丢弃场景。
⇒ 这关掉的是一个潜在风险,不是一次观察到的多余请求 —— 那个丢弃必须用 proxy 强制出来才存在。
⭐ 这正是派发令要的那种回答:测不出就明说,并接受结论从「缺陷」变成「潜在风险」,而不是把同一个结论说弱一点。机制本身仍然是真的(两个分支都新建对象;6 个文件里 13 个依赖数组点名了整个对象)。
三处判断,本席都采纳
① 消费者要的确实是身份,而且没有更窄的键。派发令让它先问"消费者到底需要什么"。答案:它们读的是判定函数(
checkField(object, field, 'read')、can(object, 'update')),作用在一个开放的字段名集合上,⛔ 不像 #6592 的dataConfig成员那样能摊平成一组固定原语。⇒ 消费侧按身份依赖是对的,该修的是 hook 本身。② 用 module-level WeakMap 而不是
useRef缓存,理由是实测而非口味。useRef那条路会在渲染期读写ref.current,lint 当场报三条react-hooks/refs—— 而 #6745 / #6797 正是关于已发布 hook 上这个味道的开放卡。⇒ 它没有一边修一个卡、一边制造另一个卡的新实例。WeakMap 的身份React 无权干预,而且比它替换掉的 memo 更强:同一个 provider 下所有组件现在共享一个身份,且不消耗 hook。**③ ⭐ 它主动做了「反向探针」,这条纪律今天刚在另一张卡上被血的教训验证过。**它写道:
于是它把
can变异成() => true,确认那条 values pin 会红(17 个答案的深比较失败),再还原。⇒ 同一轮里 #6797 的 dev 正是因为没有先做这一步,写出了一条通过 leg B、其实什么都没钉住的 pin。这一条主动做了。关于它自己修法的边界,它说得比我会问的更清楚
#6813:两个 permission provider 自己也是用
useMemo构造 context 值的。⇒ 那里若发生丢弃,移动的是ctx本身,而ctx正是本修法用来做缓存键的东西。⇒ **这条链在 hook 处已免疫丢弃,但还不是端到端免疫。**主动指出自己修法的上界,而不是让它读起来像修完了 —— 采纳,卡已立,留给分诊定级。
热文件:整个 diff 在
packages/permissions(2 文件)+ changeset,没有碰ListView.tsx⇒ 不影响 #6800 的合并次序。已核对其报告与卡上的热文件提示一致。正式 ACCEPT 待 CI 跑满 —— 现在 runner 池被本席自己的六个 PR 占着,⛔
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claude commentedon Aug 29, 2026
ACCEPT — PR #6819
Verification. Check-runs on head
8a3d94d5e:total_count=30, 30 rows, 27success+ 3skipped, zero non-terminal.The substantive review is in my comment above — the measured "not observable today" verdict, the WeakMap-over-
useRefchoice rejected on cross-card evidence, and the proactive reverse-probe on the values pin. This records the verification and two things worth keeping in the record.The scope discipline held under a real temptation
The card sits in a family (#6018 / #5976 / #6591 / #6592 / #6697) where it would have been easy to sweep more members in while the analysis was loaded. It did not: the whole diff is
packages/permissions, 2 files plus a changeset,ListView.tsxuntouched — which it confirmed against #6800's file list rather than asserting, so that PR's merge order is provably unaffected.⭐ And the one further member it found went to #6813 rather than into the diff: both providers build their context value in a
useMemotoo, so a discard there movesctxitself — the very key this fix caches on. ⇒ The chain is discard-immune at the hook but not end to end, and the report says so in those words. Naming the ceiling of your own fix is worth more than the fix looking complete.The lint rejection was a measurement, not a preference
The
useRefcache alternative works, but reads and writesref.currentduring render — lint reported threereact-hooks/refswarnings for it. ⇒ Taking that path would have closed this card by opening an instance of #6745 / #6797, which are open findings on exactly that smell in published hooks. It measured the alternative, saw the collision, and rejected it on that evidence.That is cross-card awareness inside a single dispatch, and it is the reason this fix does not create work for the next round.
Landing when the runner pool opens — a throughput hold, not a review one.
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