From cae86036aaa8929805bd158b4f269e999a87625c Mon Sep 17 00:00:00 2001
From: Stanislav Malyshev <smalyshev@gmail.com>
Date: Thu, 9 Feb 2017 13:30:12 -0800
Subject: [PATCH] Allow fields to define their own merge strategy via callback.

Change-Id: Ic1cc1581f07381224d3f4fcba4feb1eac7085057
---
 .../search/SearchIndexFieldDefinition.php     | 15 ++++++++++
 .../includes/search/SearchIndexFieldTest.php  | 30 +++++++++++++++----
 2 files changed, 39 insertions(+), 6 deletions(-)

diff --git a/includes/search/SearchIndexFieldDefinition.php b/includes/search/SearchIndexFieldDefinition.php
index 910fd77acc..04344fdadd 100644
--- a/includes/search/SearchIndexFieldDefinition.php
+++ b/includes/search/SearchIndexFieldDefinition.php
@@ -33,6 +33,11 @@ abstract class SearchIndexFieldDefinition implements SearchIndexField {
 	 */
 	protected $subfields = [];
 
+	/**
+	 * @var callable
+	 */
+	private $mergeCallback;
+
 	/**
 	 * SearchIndexFieldDefinition constructor.
 	 * @param string $name Field name
@@ -91,6 +96,9 @@ abstract class SearchIndexFieldDefinition implements SearchIndexField {
 	 * @return SearchIndexField|false New definition or false if not mergeable.
 	 */
 	public function merge( SearchIndexField $that ) {
+		if ( !empty( $this->mergeCallback ) ) {
+			return call_user_func( $this->mergeCallback, $this, $that );
+		}
 		// TODO: which definitions may be compatible?
 		if ( ( $that instanceof self ) && $this->type === $that->type &&
 			$this->flags === $that->flags && $this->type !== self::INDEX_TYPE_NESTED
@@ -125,4 +133,11 @@ abstract class SearchIndexFieldDefinition implements SearchIndexField {
 	 */
 	abstract public function getMapping( SearchEngine $engine );
 
+	/**
+	 * Set field-specific merge strategy.
+	 * @param callable $callback
+	 */
+	public function setMergeCallback( $callback ) {
+		$this->mergeCallback = $callback;
+	}
 }
diff --git a/tests/phpunit/includes/search/SearchIndexFieldTest.php b/tests/phpunit/includes/search/SearchIndexFieldTest.php
index 9c10e49976..a5a1b7acc0 100644
--- a/tests/phpunit/includes/search/SearchIndexFieldTest.php
+++ b/tests/phpunit/includes/search/SearchIndexFieldTest.php
@@ -18,14 +18,23 @@ class SearchIndexFieldTest extends MediaWikiTestCase {
 
 	/**
 	 * @dataProvider getMergeCases
+	 * @param $t1
+	 * @param $n1
+	 * @param $t2
+	 * @param $n2
+	 * @param $result
 	 */
 	public function testMerge( $t1, $n1, $t2, $n2, $result ) {
-		$field1 = $this->getMockBuilder( 'SearchIndexFieldDefinition' )
-			->setMethods( [ 'getMapping' ] )
-			->setConstructorArgs( [ $n1, $t1 ] )->getMock();
-		$field2 = $this->getMockBuilder( 'SearchIndexFieldDefinition' )
-			->setMethods( [ 'getMapping' ] )
-			->setConstructorArgs( [ $n2, $t2 ] )->getMock();
+		$field1 =
+			$this->getMockBuilder( SearchIndexFieldDefinition::class )
+				->setMethods( [ 'getMapping' ] )
+				->setConstructorArgs( [ $n1, $t1 ] )
+				->getMock();
+		$field2 =
+			$this->getMockBuilder( SearchIndexFieldDefinition::class )
+				->setMethods( [ 'getMapping' ] )
+				->setConstructorArgs( [ $n2, $t2 ] )
+				->getMock();
 
 		if ( $result ) {
 			$this->assertNotFalse( $field1->merge( $field2 ) );
@@ -35,5 +44,14 @@ class SearchIndexFieldTest extends MediaWikiTestCase {
 
 		$field1->setFlag( 0xFF );
 		$this->assertFalse( $field1->merge( $field2 ) );
+
+		$field1->setMergeCallback(
+			function ( $this, $that ) {
+				return "test";
+			}
+		);
+		$this->assertEquals( "test", $field1->merge( $field2 ) );
+
 	}
+
 }
-- 
2.20.1