[6.x] Look up the Comb index once when paginating search results

src/Search/Comb/Query.php

@@ -6,8 +6,10 @@
 
 class Query extends QueryBuilder
 {
+    protected $lookups = [];
+
     public function getSearchResults($query)
     {
-        return $this->index->lookup($this->query);
+        return $this->lookups[$this->query] ??= $this->index->lookup($this->query);
     }
 }

tests/Search/Comb/QueryTest.php

@@ -0,0 +1,41 @@
+<?php
+
+namespace Tests\Search\Comb;
+
+use Mockery;
+use PHPUnit\Framework\Attributes\Test;
+use Statamic\Search\Comb\Index;
+use Statamic\Search\Comb\Query;
+use Tests\TestCase;
+
+class QueryTest extends TestCase
+{
+    #[Test]
+    public function paginating_looks_up_the_index_once()
+    {
+        $index = Mockery::mock(Index::class);
+        $index->shouldReceive('lookup')->with('foo')->once()->andReturn(collect([
+            ['reference' => 'a', 'search_score' => 2],
+            ['reference' => 'b', 'search_score' => 1],
+        ]));
+
+        $paginator = (new Query($index))->query('foo')->withoutData()->paginate(1);
+
+        $this->assertEquals(2, $paginator->total());
+        $this->assertEquals(['a'], $paginator->getCollection()->map->reference->all());
+    }
+
+    #[Test]
+    public function changing_the_query_looks_up_the_index_again()
+    {
+        $index = Mockery::mock(Index::class);
+        $index->shouldReceive('lookup')->with('foo')->once()->andReturn(collect([['reference' => 'a']]));
+        $index->shouldReceive('lookup')->with('bar')->once()->andReturn(collect([['reference' => 'b']]));
+
+        $builder = (new Query($index))->withoutData();
+
+        $this->assertEquals(['a'], $builder->query('foo')->get()->map->reference->all());
+        $this->assertEquals(['b'], $builder->query('bar')->get()->map->reference->all());
+        $this->assertEquals(['a'], $builder->query('foo')->get()->map->reference->all());
+    }
+}