finding(plugin-grid): a standalone ObjectGrid still renders an off-spec rowHeight as `medium`, the third answer to the question #4440 unified

[yinlianghui]

Found while implementing #4440. Observation-class: nothing a user hits today, and no fix is proposed here.

What

#4440 made two surfaces agree that an off-spec rowHeight gets no density — @object-ui/core's rowHeightToDensityMode and @object-ui/react's mapDensity. A third surface answers the same question without consulting either.

packages/plugin-grid/src/ObjectGrid.tsx:371 takes the value straight into state:

const [rowHeightMode, setRowHeightMode] =
  useState<'compact' | 'short' | 'medium' | 'tall' | 'extra_tall'>(schema.rowHeight ?? 'compact');

and renders it through a ternary chain whose final else is the medium styling (ObjectGrid.tsx:1834-1841, and again for cellClassName at 2370-2377):

rowHeightMode === 'compact'   ? 'px-3 py-1 h-9 text-[13px] leading-tight'
  : rowHeightMode === 'short'      ? 'px-3 py-1 h-9 text-[13px] leading-normal'
  : rowHeightMode === 'tall'       ? 'px-3 py-2.5 h-14 text-sm'
  : rowHeightMode === 'extra_tall' ? 'px-3 py-3.5 h-16 text-sm leading-relaxed'
  : 'px-3 py-1.5 h-11 text-[13px] leading-normal'   // ← medium, and everything unrecognized

So for the same garbage rowHeight, the system now says: ListView → compact (32px), the spec bridge → no density at all, a standalone ObjectGrid → medium (44px). Note the ?? on line 371 makes ABSENT resolve to compact while OFF-SPEC resolves to medium — the same absent-vs-off-spec split #4440 removed from ListView.

Only the standalone path is affected: when ListView owns the grid it overwrites the prop with a value derived from density.mode (ListView.tsx:1676-1698, one of compact/medium/tall), so nothing off-spec survives that hop.

Why it is observation-class and not a defect today

Unreachable by any metadata that exists. The three-repo sweep run for #4352 (PR #4439), re-run at newer HEADs for #4440, found zero authored off-spec rowHeight values across objectui, the objectstack example apps and one downstream app; every authored value is one of the five RowHeightSchema admits.

It is also a materially weaker case than #4440 was. This is not a mapping table with a catch-all branch — it is a rendering ternary whose default is a style, and a component's own last-resort styling default is a legitimate thing to have. What is odd is only that the default it picks (medium) differs from the default the same component picks when the key is absent (compact).

The decision, when someone takes it

1. Narrow at the boundary — validate schema.rowHeight into the state exactly as ListView now does, so off-spec and absent both land on compact. This is the finding(core): rowHeightToDensityMode coerces an off-spec rowHeight to comfortable, the opposite of what the spec bridge now does with the same input #4440 answer applied to the third surface, and it makes the ?? on line 371 mean one thing.
2. Leave it and write down why — a leaf renderer's terminal else is not a vocabulary bridge, and forcing every styling ternary to pre-validate its input has a cost. If that is the intended position, say so at line 371 and name the two surfaces that decided otherwise, so the next reader does not file this twice.

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[yinlianghui]

CLAIM — session session_017Qqyix2QcnpUC9XeYVDzx3 (objectui whole-repo seat), branch claude/issue-4443-objectgrid-rowheight-boundary.

Ruling (delegated authority, product-long-term-stability; open veto window): option 1 — narrow at the boundary.

The card fairly notes a leaf renderer's terminal else is legitimate styling, but that is not the part being ruled on. The incoherence is that ONE component gives absent → compact and off-spec → medium (the ?? on ObjectGrid.tsx:371 vs the ternary's terminal else), which is exactly the absent-vs-off-spec split #4440 removed from ListView — and the family doctrine is one answer for off-spec input everywhere (core abstains→ListView defaults compact; bridge abstains; standalone ObjectGrid must not invent a third answer). Validate schema.rowHeight into the initial state exactly as ListView now does, so off-spec and absent both land on compact and line 371's ?? means one thing. The ternary chain itself is untouched — medium remains a real value and the terminal else remains its styling arm.

Test half (red-first): standalone ObjectGrid with an off-spec rowHeight (e.g. 'garbage', plus a prototype-member spelling like 'toString' for family symmetry with #4442) — pre-fix the rows carry the medium classes (h-11), post-fix the compact classes (h-9). Cover both ternary copies (row className ~1834 and cellClassName ~2370). Also pin absent → compact (must stay green pre- and post-fix). Keep the test in packages/plugin-grid — do NOT touch the react agreement pin (RowHeightDensityAgreement.test.ts); that file is #4442's surface.

Grading: runtime-only for off-spec input; changeset patch for @object-ui/plugin-grid unless the emitted .d.ts moves (it should not).

Sequencing gate: PR #4450 (#4045's button-type population fix) is armed and touches files across the repo, possibly including plugin-grid — dev polls for #4450 in origin/main before creating the worktree.

Surface (mutual exclusion): packages/plugin-grid/src/ObjectGrid.tsx + one new/extended test file in packages/plugin-grid + one changeset. Disjoint from in-flight #4433 (plugin-calendar), #4325 (fields), #4442 (react spec-bridge).

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Generated by Claude Code

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Generated by Claude Code