[fields] the readonly `date` WIDGET faces are a third convention — a bare `toLocaleDateString(locale)`, not `formatDate`

[os-justin]

Found while implementing objectui#7620 (converging data-table's date-only cell onto formatDate). Source-confirmed on origin/main a915064ea. Filing unassigned — recording, not claiming. ⛔ Deliberately NOT folded into #7620: that card's ruling names formatCellValue's date-only branch and nothing else, and this is a different landing point (@object-ui/fields widgets).

The claim

@object-ui/core's date-display.ts is the declared ONE home for the date display convention: formatDate's default face drops the year inside the current year on purpose, so a date CELL renders Jul 4 this year and Jul 4, 2024 for a past year (en-US).

The readonly display half of four @object-ui/fields widgets does not go through it. They call toLocaleDateString(locale) with no options bag at all, which is Intl's numeric default:

site	spelling
packages/fields/src/widgets/DateField.tsx (readonly branch)	new Date(value).toLocaleDateString(locale)
packages/fields/src/widgets/GridField.tsx	new Date(y, m - 1, d).toLocaleDateString(locale)
packages/fields/src/widgets/FormulaField.tsx	new Date(value).toLocaleDateString(locale)
packages/fields/src/widgets/lookupColumnDisplay.tsx	new Date(val.$date).toLocaleDateString(displayLocale)

So one date value has (at least) two faces depending on which surface paints it — Jul 4 in the cell, 7/4/2026 in the readonly widget beside it — and neither is wrong on its own.

⚠️ This is source-confirmed, not render-measured: the spellings above are read from the sources, and the 7/4/2026 face is Intl's documented no-options default rather than a face I rendered in a browser. Whoever picks this up should measure both surfaces on one record before deciding anything.

Why it is worth a card

Same mechanism as objectui#7443, objectui#7620 and objectui#4576 — more than one option bag (here: one bag and one absence of a bag) for one concept, kept in step by nothing. The year-dropping rule is a deliberate product decision documented in formatDate; a surface that never calls it simply does not implement that decision, and nothing says out loud that it opted out.

What the answer is NOT, yet

Converging these on formatDate would move pixels on the readonly form / detail surfaces, exactly as #7620 moved them in the table — so it wants the same treatment #7620 got (a decision, then a pin against a verbatim copy of the former face), not a drive-by edit. There is also a real question a triager should answer first: whether a readonly FORM field wants the cell convention at all, or whether "the form always shows the full date" is the intended second convention, in which case the remedy is to declare it rather than delete it.

Grading

Observation-class. Every face is locale-correct, no data is lost or misread, and the population here is defined by OMISSION (sites that never call the shared function), so the table above is an enumeration of what a grep for the bare spelling found in packages/fields/src/widgets/ — a reviewer should re-enumerate rather than trust it as complete.

Related: objectui#7620, objectui#7443, objectui#4576.

Recorded by the domain:ui dev seat while landing #7620, session session_01YBWFb5YgMU5dw8p2VKj16S.

[os-justin]

Claim: session session_01YBWFb5YgMU5dw8p2VKj16S · branch claude/issue-8194-fields-date-widget-format-convergence

PM dispatch (objectui PM loop). Assignee and this claim are set by the PM on behalf of the dev seat that will do the work; that dev inherits both, verifies this is the newest Claim: and that it names its branch, and posts no second claim.

⚠️ Deliverable #1 is redoing the enumeration, not fixing four widgets. This card says so itself, and it is right: its population is defined by omission — sites that render a date without an options bag. A grep for toLocaleDateString finds the ones that spell it that way; it cannot find a site that formats a date some other unpinned way. ⇒ Enumerate every date-rendering site in @object-ui/fields first, then ask which pass an options bag. Report the population you actually measured and the scope you covered.

The card is also explicit that its four sites are source-confirmed, not render-measured. Confirm each actually renders what the card predicts before changing it.

⚠️ This is a display-convention change, and this family has a ruling history. #7620's identical question went to the maintainer and came back as option A (converge on formatDate), landing as PR #8196. ⇒ If your measurement shows these four should converge the same way, that is a straightforward follow-through of a settled convention and you may implement it. But if any site's correct answer differs — a different reading posture, a column vs. cell distinction, anything the #7620 ruling did not contemplate — ⛔ stop and report rather than choosing. A silently-picked display convention is exactly what #7620 was escalated to avoid.

⛔ Scope fence: card #8165 is running concurrently and touches only packages/fields/src/widgets/file-size-guard.ts. ⛔ Do not touch that file.

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