fix: only save custom fields the imported row carried [3.x]

[ManukMinasyan]

Found while business-reviewing #192 end-to-end against a real consumer app.

The bug

ImporterBuilder::saveValues() delegated to saveCustomFields():

$this->customFields()->each(function (CustomField $customField) use ($customFields, $tenant): void {
    $value = $customFields[$customField->code] ?? null;   // ← absent becomes null
    $this->saveCustomFieldValue($customField, $value, $tenant);
});

That semantic is correct for a form — it renders every field, so a field absent from the submitted state means the user cleared it. It is destructive for an import, where a CSV legitimately maps a subset of columns and absent means "not in this file".

Result: an update import that mapped one custom field silently wiped every other custom field on the record.

after create:                   referral_source => 'Continuum of Care'   caseworker => 'Alex Rivera'
after update mapping only one:  referral_source => 'Street Outreach'     caseworker => null   ← wiped

Why it hasn't bitten yet

saveValues() returns early when ImportDataStorage::pull() is empty. Consumers that strip custom_fields_* keys from $this->data before Filament's Importer::fillRecord() runs never populate the storage at all, so saveValues() no-ops and nothing is written — or wiped. In the app I reviewed, that describes all 11 importers: custom field values were never persisted, which also hid this.

Fix that consumer-side ordering and the wipe becomes live immediately. So this is latent today and load-bearing the moment anyone gets the ordering right.

Fix

saveValues() now writes only the codes the row actually carried:

$this->getAllFields()
    ->filter(fn (CustomField $field): bool => array_key_exists($field->code, $customFieldsData))
    ->each(fn (CustomField $field) => $this->model->saveCustomFieldValue(
        $field, $customFieldsData[$field->code], $tenant,
    ));

Also fixes HasCustomFields::saveCustomFieldValue(), which was missing the ?Model $tenant = null parameter its UsesCustomFields implementation has accepted since multi-tenancy landed. PHPStan caught it as soon as the interface was called with three arguments. Any implementer following the contract would silently drop tenant scoping.

Verification

• New tests/Feature/Imports/ImporterBuilderSaveValuesTest.php — three cases: carried fields are saved, uncarried fields are untouched, empty payload is a no-op. Confirmed the "untouched" case fails without the fix (null instead of 'Alex Rivera'), so it isn't vacuous.
• pest --parallel — 764 passed, 0 failed
• phpstan analyse — no errors
• pint --dirty, rector --dry-run — clean
• Verified end-to-end in a consumer app: with this plus the consumer's fill-ordering fix, a subset-column update import preserves the unmapped values.

Relationship to #192

Independent, both in the import path, both should land in the same release. #192 stops optional custom fields from failing validation on a mapped-but-empty column; this stops a subset-column import from wiping data once values actually reach the save path.

[Copilot]

Pull request overview

This PR fixes destructive behavior in the import pipeline where updating a record with a subset of mapped custom-field columns could unintentionally wipe all other custom-field values, and aligns the HasCustomFields contract with the multi-tenancy-aware implementation.

Changes:

• Update ImporterBuilder::saveValues() to persist only custom field codes actually present in the imported row payload.
• Fix the HasCustomFields::saveCustomFieldValue() contract to accept an optional tenant model parameter.
• Add feature tests covering: saving carried fields, leaving uncarried fields untouched, and no-op behavior when no custom-field columns were carried.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
tests/Feature/Imports/ImporterBuilderSaveValuesTest.php	Adds regression tests to prevent imports from wiping uncarried custom fields.
src/Models/Contracts/HasCustomFields.php	Updates interface signature to include optional tenant parameter for tenant-scoped value saving.
src/Filament/Integration/Builders/ImporterBuilder.php	Changes save logic to write only row-carried custom field codes instead of nulling absent ones.