From a2ee8a267f166b5c3d4d7300566ba2631fd02fd0 Mon Sep 17 00:00:00 2001
From: "claude[bot]" <209825114+claude[bot]@users.noreply.github.com>
Date: Sat, 5 Sep 2026 19:53:48 +0000
Subject: [PATCH] chore(fields): narrow the datetime style cast, and make the
 #7443 changeset accurate for consumers
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Two follow-ups recorded from the contract review of objectui#7621, neither of
which gated its PASS (objectui#7747).

The `DateTimeCellRenderer` style cast goes from `as any` to
`(field as DateTimeFieldMetadata | undefined)`. Some cast is load-bearing —
`FieldMetadata` is a 37-member union and `BaseFieldMetadata` carries no
`format`, so the bare read is `TS2339` — but `as any` was wider than the job.
`DateTimeFieldMetadata` is exported from `@object-ui/types` and this file
already imports from there, so the narrow cast cost nothing. It is type-level
only: the emitted expression is unchanged, and the file's
`@typescript-eslint/no-explicit-any` warning count drops 46 to 45, the one
removed being the line changed here.

The `7443-datetime-compact-style.md` changeset claimed every existing cell
renders byte-identically. That is true measured in this repository — no
in-repo `datetime` field authors a `format` — but a changeset is a release-note
input read by consumers who are not this repository, and objectui#7621 made
`DateTimeCellRenderer` start reading `field.format`. The sentence now names its
own precondition and the measured consequence: an authored `format` other than
`'compact'` is neither rejected nor passed through, it silently selects the
verbose `formatDateTime` default. The note also states the gap rather than
papering over it — `format` has no declared value vocabulary on a datetime
field in either `@object-ui/types` or `@objectstack/spec`. Only the prose
changed; the frontmatter and its three package names are byte-identical.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01KbJQ1y1J12nZxYzFWhP8Q3
---
 .changeset/7443-datetime-compact-style.md     | 18 ++++++++++++++++--
 .../7747-datetime-format-cast-narrowing.md    | 19 +++++++++++++++++++
 packages/fields/src/index.tsx                 |  8 ++++++--
 3 files changed, 41 insertions(+), 4 deletions(-)
 create mode 100644 .changeset/7747-datetime-format-cast-narrowing.md

diff --git a/.changeset/7443-datetime-compact-style.md b/.changeset/7443-datetime-compact-style.md
index c7190f6f2..70900b838 100644
--- a/.changeset/7443-datetime-compact-style.md
+++ b/.changeset/7443-datetime-compact-style.md
@@ -13,8 +13,22 @@ The cell now reads `field.format` (it destructured `value` only, so a
 `datetime` field could not reach the style vocabulary a `date` field has) and
 renders through the shared function, and `data-table`'s `formatCellValue`
 calls `formatDateTime` instead of a third, independently authored option bag.
-Every existing cell renders byte-identically; `'compact'` is today's face
-named and rehoused, not a new one.
+Every existing cell without an authored `format`, and every cell authoring
+`'compact'`, renders byte-identically; `'compact'` is today's face named and
+rehoused, not a new one. A `datetime` field that authors any OTHER non-empty
+`format` does change: the cell previously ignored `field` altogether and always
+painted the compact face, and now anything other than `'compact'` selects the
+verbose `formatDateTime` default — measured as `Jul 4, 2024, 07:00 AM` in
+`en-US` for the instant whose compact face is `7/4/2024 7:00 am`. An
+unrecognised value is neither rejected nor passed through; it silently lands on
+that verbose face. No `datetime` field in this repository authors a `format`, so
+no cell here moves — a consumer that authored one is the case this sentence is
+for. Note that `format` has no declared value vocabulary to check a value
+against: `@object-ui/types` types it `format?: string`, and `@objectstack/spec`
+carries one free-form `format?: string` on its shared field schema, described
+"Format string (e.g. email, phone)" and accepting any string. `'compact'` is
+therefore the only value with a defined `datetime` meaning, and every other
+value means "the verbose face" by fallthrough rather than by design.
 
 Additive, no signature change: `formatDateTime(value, options?)` is unchanged
 and `formatDateTime(v, { locale })` keeps meaning what it meant.
diff --git a/.changeset/7747-datetime-format-cast-narrowing.md b/.changeset/7747-datetime-format-cast-narrowing.md
new file mode 100644
index 000000000..b9f09b92e
--- /dev/null
+++ b/.changeset/7747-datetime-format-cast-narrowing.md
@@ -0,0 +1,19 @@
+---
+---
+
+Narrow the `DateTimeCellRenderer` style cast from `as any` to the subtype that
+actually declares the property (objectui#7747).
+
+`const style = (field as any)?.format || 'compact'` becomes
+`(field as DateTimeFieldMetadata | undefined)?.format`. Some cast is
+load-bearing — `FieldMetadata` is a 37-member union and `BaseFieldMetadata`
+carries no `format`, so the bare read is `TS2339` — but `as any` was wider than
+the job: `DateTimeFieldMetadata` is exported from `@object-ui/types`, which this
+file already imports from, so the narrow cast was available at zero cost. The
+difference that buys: `as any` would also have silenced a typo in the property
+name, and the narrow cast will not.
+
+Type-level only; no package is released by this change. The emitted expression
+is identical, so every cell renders exactly what it rendered before —
+`'compact'` and an absent or empty `format` keep the compact face, and any
+other value keeps selecting the verbose `formatDateTime` default.
diff --git a/packages/fields/src/index.tsx b/packages/fields/src/index.tsx
index bb0974998..c16ba226e 100644
--- a/packages/fields/src/index.tsx
+++ b/packages/fields/src/index.tsx
@@ -7,7 +7,7 @@
  */
 
 import React from 'react';
-import type { FieldMetadata, SelectOptionMetadata } from '@object-ui/types';
+import type { DateTimeFieldMetadata, FieldMetadata, SelectOptionMetadata } from '@object-ui/types';
 import { ComponentRegistry, percentDisplayValue, getRecordDisplayName, humanizeLabel, isMissingForRequired, formatDate, formatDateTime, formatDateTimeCompactParts, formatRelativeDate, type ComponentMeta, type DateDisplayOptions } from '@object-ui/core';
 // The platform's own value-shape contract, asked rather than restated
 // (objectui#6744). See `locationStoredValueSchemaFor` below for why this is a
@@ -882,7 +882,11 @@ export function DateTimeCellRenderer({ value, field }: CellRendererProps): React
   // (objectui#7443). `||`, not `??`, matches the `date` cell and keeps an
   // authored empty string on the compact face rather than dropping it into
   // the verbose default.
-  const style = (field as any)?.format || 'compact';
+  // `FieldMetadata` is a 37-member union and `BaseFieldMetadata` carries no
+  // `format`, so the bare property read is `TS2339` — SOME cast is load-bearing.
+  // `DateTimeFieldMetadata` is the narrowest one that carries it (objectui#7747);
+  // `as any` would also silence a typo in the property name, this does not.
+  const style = (field as DateTimeFieldMetadata | undefined)?.format || 'compact';
 
   // The compact face is painted in two halves — the time is muted and offset
   // — so this branch asks the shared module for the halves rather than the