feat(query): add field masking span query

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: Spamercz

doc/02-query-objects.md

@@ -695,6 +695,19 @@ new \Spameri\ElasticQuery\Query\SpanMulti(
 );
 ```
 
+##### FieldMaskingSpan Query
+Mask a span clause to act on a different field — enables span queries across multiple fields.
+- Class: `\Spameri\ElasticQuery\Query\FieldMaskingSpan`
+- [Documentation](https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-span-field-masking-query.html)
+- [Implementation](https://github.com/Spameri/ElasticQuery/blob/master/src/Query/FieldMaskingSpan.php)
+
+```php
+new \Spameri\ElasticQuery\Query\FieldMaskingSpan(
+	query: new \Spameri\ElasticQuery\Query\SpanTerm('text.stems', 'fox'),
+	field: 'text',
+);
+```
+
 ##### SpanTerm Query
 Match a single term in a span-aware way.
 - Class: `\Spameri\ElasticQuery\Query\SpanTerm`

src/Query/FieldMaskingSpan.php

@@ -0,0 +1,40 @@
+<?php
+
+declare(strict_types = 1);
+
+namespace Spameri\ElasticQuery\Query;
+
+/**
+ * @see https://www.elastic.co/guide/en/elasticsearch/reference/current/query-dsl-span-field-masking-query.html
+ */
+class FieldMaskingSpan implements \Spameri\ElasticQuery\Query\LeafQueryInterface
+{
+
+	public function __construct(
+		private \Spameri\ElasticQuery\Query\LeafQueryInterface $query,
+		private string $field,
+	)
+	{
+	}
+
+
+	public function key(): string
+	{
+		return 'field_masking_span_' . $this->field . '_' . $this->query->key();
+	}
+
+
+	/**
+	 * @return array<string, array<string, mixed>>
+	 */
+	public function toArray(): array
+	{
+		return [
+			'field_masking_span' => [
+				'query' => $this->query->toArray(),
+				'field' => $this->field,
+			],
+		];
+	}
+
+}

tests/SpameriTests/ElasticQuery/Query/FieldMaskingSpan.phpt

@@ -0,0 +1,64 @@
+<?php declare(strict_types = 1);
+
+namespace SpameriTests\ElasticQuery\Query;
+
+require_once __DIR__ . '/../../bootstrap.php';
+
+
+class FieldMaskingSpan extends \Tester\TestCase
+{
+
+	private const INDEX = 'spameri_test_query_field_masking_span';
+
+
+	public function setUp(): void
+	{
+		$ch = \curl_init();
+		\curl_setopt($ch, \CURLOPT_URL, \ELASTICSEARCH_HOST . '/' . self::INDEX);
+		\curl_setopt($ch, \CURLOPT_RETURNTRANSFER, 1);
+		\curl_setopt($ch, \CURLOPT_CUSTOMREQUEST, 'PUT');
+		\curl_setopt($ch, \CURLOPT_HTTPHEADER, ['Content-Type: application/json']);
+
+		\curl_exec($ch);
+	}
+
+
+	public function testToArray(): void
+	{
+		$span = new \Spameri\ElasticQuery\Query\FieldMaskingSpan(
+			query: new \Spameri\ElasticQuery\Query\SpanTerm('text.stems', 'fox'),
+			field: 'text',
+		);
+
+		$array = $span->toArray();
+
+		\Tester\Assert::same('text', $array['field_masking_span']['field']);
+		\Tester\Assert::true(isset($array['field_masking_span']['query']['span_term']));
+	}
+
+
+	public function testKey(): void
+	{
+		$span = new \Spameri\ElasticQuery\Query\FieldMaskingSpan(
+			new \Spameri\ElasticQuery\Query\SpanTerm('text.stems', 'fox'),
+			'text',
+		);
+
+		\Tester\Assert::same('field_masking_span_text_span_term_text.stems_fox', $span->key());
+	}
+
+
+	public function tearDown(): void
+	{
+		$ch = \curl_init();
+		\curl_setopt($ch, \CURLOPT_URL, \ELASTICSEARCH_HOST . '/' . self::INDEX);
+		\curl_setopt($ch, \CURLOPT_RETURNTRANSFER, 1);
+		\curl_setopt($ch, \CURLOPT_CUSTOMREQUEST, 'DELETE');
+		\curl_setopt($ch, \CURLOPT_HTTPHEADER, ['Content-Type: application/json']);
+
+		\curl_exec($ch);
+	}
+
+}
+
+(new FieldMaskingSpan())->run();