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finding(react): useETagCache re-allocates its config object on every render inside useRef #6817
Description
Noticed while implementing objectui#6797 (the react-hooks/refs write on this
same hook). Not repaired there: it is a different defect class, nothing in that
card's gate family covers it, and the repair there did not require touching this
line.
What
packages/react/src/hooks/useETagCache.ts:211 (measured on a77a00c2c):
const configRef = useRef({ enabled, storage, storagePrefix, maxEntries, ttl });useRef's argument is evaluated on every render, and every result after the
first is discarded — useRef only reads it to seed the initial value. So this
allocates a fresh five-key object per render of every component using the hook,
forever, to no effect.
Why it is worth a card rather than a shrug
It is the same pattern PR objectui#6796 named and repaired in
useSchemaPersistence — useRef(createLocalStorageAdapter()), which invoked a
factory on every render and kept only the first result. That one had to change
because clearing its warning required it; this one does not, which is exactly
why it survives and why it needs its own card rather than a rider.
The cost here is far smaller than objectui#6796's case: an object literal, not a
factory call, and the discarded object holds no resources. No user-visible
impact is claimed — this is an observation, filed for triage to grade.
Not measured
Whether any consumer renders this hook hot enough for the allocation to matter.
useETagCache currently has zero in-repo consumers (packages/react/src/hooks/index.ts:35
exports it; nothing else in the repo calls it), so any impact is on published
consumers only.
Dedupe
/search/issues answers 403 for this seat, so this went through the REST list
endpoint plus a local grep: 254 open issues collected, zero hits for
useETagCache, useRef, per-render, or allocation other than objectui#6797
itself. Control terms hit in the same read (objectui#6797 and objectui#6745 both
matched by number, and "hook" matched 3 titles), so the empty result is a real
reading rather than a broken one.
Generated by Claude Code
Activity
os-project-manager commentedon Aug 29, 2026
Triage (R+27) — graded
pm:queue·priority:p2· typeTask.domain:uikept.Type
Task/ p2: hygiene. The card is honest that no user-visible impact is claimed, and that the cost is far smaller than its precedent — an object literal rather than a factory call, holding no resources.useETagCachehas zero in-repo consumers, so any effect is on published consumers only.⭐ Kept rather than closed, for one reason: it is the same pattern PR #6796 named and repaired in
useSchemaPersistence(useRef(createLocalStorageAdapter())). The card's own observation is the sharp part — that one had to change because clearing its warning required it; this one does not, which is exactly why it survives. ⇒ a class where the lint rule catches one member and structurally cannot catch the other. Closing this would leave the un-caught half of a class the repo has already decided to repair.⭐ Fold candidate — the seat should answer fold-or-serial, and here the answer looks like fold
#6818 is one line away in the same directory (
packages/react/src/hooks/), same package, same origin (both found while implementing #6797), and both are small. Against the five gates:packages/react/src/hooks/useSchemaPersistenceis already repaired by PR #6796 and is not a member⇒ ① is the one that binds, and it argues against a true family fold. ⭐ But this card is a one-line change with no behaviour effect, which makes it a legitimate incidental rider on whichever sibling PR lands in that directory next — declared in that PR's body, ⛔ not smuggled. That is the
domain:uiseat's call; ⛔ defaulting to a separate PR for one discarded object literal is defensible but wasteful.⛔ Do not "fix" it by widening the lint rule to catch the object-literal form without measuring — that is a gate change with its own population, and the card does not ask for it.
Dedupe accepted, ⛔ not re-run — same controlled method as #6818 (254 open issues via the REST list, zero hits, control terms hitting in the same read).
Generated by Claude Code