fix: surface validation error for incomplete date segment values

[AKnassa]

Problem

When a user partially fills a date field (e.g., clears the month segment but leaves year and day set), no validation error was surfaced. The value state remains null for incomplete dates — so getValidationResult never saw it as invalid, and the field appeared valid even though the user had entered an incomplete value.

Affects: DateField, DatePicker, DateRangePicker, TimeField
Fixes #9958, #9801, #9624

Solution

Introduce an isValuePartial flag that tracks whether the display buffer has some-but-not-all editable segments filled. This flag is:

• Computed in useDateFieldState from displayValue.isComplete() / displayValue.isCleared()
• Passed into getValidationResult to mark the field invalid and set valueMissing: true
• Lifted from inner DateField components up to DatePicker / DateRangePicker via a private prop (privateSetIsValuePartialProp) so the parent's validation pipeline sees it
• Reset synchronously when setValue() is called with a complete value, preventing stale errors after calendar selection

When a partial value also violates a constraint (min/max/unavailableDate), the descriptive constraint message is shown instead of the generic "Please enter a value." fallback.

Changes

• useDateFieldState.ts — adds isValuePartial to state; passes it to getValidationResult
• useDatePickerState.ts / useDateRangePickerState.ts — lift partial state from inner fields; wrap setValue to reset flags on commit
• utils.ts — getValidationResult / getRangeValidationResult accept isValuePartial; constraint errors take priority over the generic message
• useDateField.ts — commits validation on blur when partial; pushes partial state to parent; empties hidden input when partial
• useDatePicker.ts / useDateRangePicker.ts — forward privateSetIsValuePartialProp to inner fields
• useFormValidationState.ts — exports privateSetIsValuePartialProp constant
• intl/datepicker/*.json — adds incompleteValue key to all 36 locale files
• scripts/missingTranslations.js — extended to scan intl/datepicker/ subdirectories

Test plan

• DateField: clear a segment → blur → error appears; refill → error clears
• DatePicker: clear a segment → blur → error appears; select from calendar → error clears on FIRST selection
• DateRangePicker: clear a start/end segment → blur → error appears; select range → error clears on FIRST selection
• TimeField: clear hour segment → blur → error appears; refill → error clears
• Partial value with violated min/max shows descriptive message, not generic one
• isRequired validation still works as before
• validationBehavior="aria" path unaffected

[0xZeroTrace]

Hello @3bdo64 @AKnassa could you please share the expected timeline for this fix? We’ll use it to align our production deployment plans.

[AKnassa]

Thanks @0xZeroTrace. The fix is complete, CI is green, and it has full test coverage; it's just awaiting maintainer review. Nothing's blocking it: there's no change request on the PR (the lone inline comment has no actionable feedback)

[0xZeroTrace]

Thanks @AKnassa for the update. @3bdo64 Could you please look into the approval part.

[LFDanLu]

The new behavior looks promising! One issue that I found when poking around locally was that a DateField with validationBehavior="aria" now immediately displays "Please enter a value." once you fill in any of it segments from a empty state OR delete a segment if it was already filled. You can reproduce this via the

react-spectrum/packages/react-aria-components/stories/DatePicker.stories.tsx

Line 296 in f0190cf

export const DatePickerAutofill = props => (

story if you use the storybook's controls to set the validationBehavior to aria

[snowystinger]

Added some more tests for aria behaviour, please double check them. I also removed unnecessary comments, and added more checks for ui state during the tests. Please check those for correctness as well. Right now, two of the tests fail which I believe indicate bugs, one of which @LFDanLu pointed out

[snowystinger]

it's partial, we don't know if it's a violation of min or max. native date inputs still say to complete the date

<form>
<label for="start">Start date:</label>

<input
  type="date"
  id="start"
  name="trip-start"
  value="2018-07-22"
  min="2018-01-01"
  max="2018-12-31" />
  <button type="submit">Submit</button>
</form>

delete the year, then press submit

[AKnassa]

Thanks @LFDanLu @snowystinger ; went through the comments and the new tests

@LFDanLu I can reproduce the aria issue. Root cause: with validationBehavior="aria" the builtin validation is displayed in realtime, and I was feeding the live partial-segment state straight into it; so every value looked "partial" mid-edit. I'm gating the partial error behind commitValidation() so it only appears after blur, while still clearing in realtime once the date is complete

@snowystinger agreed on the min/max point; while the display is partial the committed value is stale, so constraints can't really be evaluated. I'm changing it to report only the generic incomplete message like native inputs do, and updating the two tests. Your DateRangePicker test also caught a second real bug: refilling a segment back to the same committed value never triggered a commit, so the error could never clear, fixing that too. If you'd rather partial behave differently for any of these, happy to adjust

Really appreciate the detailed feedback from you both. Updated commit coming soon; please take a look when convenient!

[0xZeroTrace]

@AKnassa Thanks for your best work.