[BUGS-7148] Handle duplicate keys in get_multiple function (#448)

* fix: Handle duplicate keys in `get_multiple` function

Signed-off-by: Souptik Datta <souptikdatta2001@gmail.com>

* add readme update

* fix whitespace 🤦‍♂️

---------

Signed-off-by: Souptik Datta <souptikdatta2001@gmail.com>
Co-authored-by: Chris Reynolds <chris.reynolds@pantheon.io>
Co-authored-by: Chris Reynolds <chris@jazzsequence.com>

README.md

@@ -111,6 +111,7 @@ There's a known issue with WordPress `alloptions` cache design. Specifically, a
 ### 1.4.4-dev ###
 * Updates security policy [[#441](https://github.com/pantheon-systems/wp-redis/pull/441)]
 * Updates Pantheon WP Coding Standards to 2.0 [[#445](https://github.com/pantheon-systems/wp-redis/pull/445)]
+* Handle duplicate keys in `get_multiple` function [[#448](https://github.com/pantheon-systems/wp-redis/pull/448)] (props @Souptik2001)
 
 ### 1.4.3 (June 26, 2023) ###
 * Bug fix: Fixes assumption that CACHE_PORT & CACHE_PASSWORD are Set. [[428](https://github.com/pantheon-systems/wp-redis/pull/428)] (props @timnolte)

object-cache.php

@@ -759,6 +759,9 @@ public function get_multiple( $keys, $group = 'default', $force = false ) {
 			$group = 'default';
 		}
 
+		// Get unique keys.
+		$keys = array_unique( $keys );
+
 		$cache = [];
 		if ( ! $this->_should_persist( $group ) ) {
 			foreach ( $keys as $key ) {

readme.txt

@@ -108,6 +108,7 @@ Please report security bugs found in the source code of the WP Redis plugin thro
 = 1.4.4-dev =
 * Updates security policy [[#441](https://github.com/pantheon-systems/wp-redis/pull/441)]
 * Updates Pantheon WP Coding Standards to 2.0 [[#445](https://github.com/pantheon-systems/wp-redis/pull/445)]
+* Handle duplicate keys in `get_multiple` function [[#448](https://github.com/pantheon-systems/wp-redis/pull/448)] (props @souptik)
 
 = 1.4.3 (June 26, 2023)  =
 * Bug fix: Fixes assumption that CACHE_PORT & CACHE_PASSWORD are Set. [[428](https://github.com/pantheon-systems/wp-redis/pull/428)] (props @tnolte)

tests/phpunit/test-cache.php

@@ -855,6 +855,31 @@ public function test_get_multiple() {
 		} else {
 			$this->assertEmpty( $this->cache->redis_calls );
 		}
+
+		$this->cache->set( 'foo3', 'bar1', 'group1' );
+		$this->cache->set( 'foo4', 'bar2', 'group1' );
+
+		$found = $this->cache->get_multiple( [ 'foo3', 'foo3', 'foo4' ], 'group1', true );
+
+		$expected = [
+			'foo3' => 'bar1',
+			'foo4' => 'bar2',
+		];
+
+		$this->assertSame( $expected, $found );
+		$this->assertEquals( 4, $this->cache->cache_hits );
+		$this->assertEquals( 1, $this->cache->cache_misses );
+		if ( $this->cache->is_redis_connected ) {
+			$this->assertEquals(
+				[
+					self::$mget_key => 2,
+					self::$set_key  => 5,
+				],
+				$this->cache->redis_calls
+			);
+		} else {
+			$this->assertEmpty( $this->cache->redis_calls );
+		}
 	}
 
 	public function test_get_multiple_partial_cache_miss() {