[6.x] Fix field filters returning all results when filtering by 0

[joshuablum]

On listing views filtering a field using 0 as the value returns items as no filter was being used instead of matching ones with an actual value of 0.

Example: A text or integer field like Levels containing values like 0, 1, 2, 3, filtering for 0 ignores the filter entirely and returns all entries.

Statamic\Query\Scopes\Filters\Fields\FieldtypeFilter::isComplete() does $values = array_filter($values) where array_filter() with no callback removes every falsy element including both the string '0' and integer 0. With the value stripped, isComplete() returns false and never applies the filter.

The fix is to replace array_filter() with explicit checks, so 0 and '0' are treated as actual values while actual empty filters (null, '') are skipped.

Related:

• Using null or 0 for title or slug causes issues #13785
• [5.x] Handle 0 values in text fields and null string in slugs #13786