refactor(media): Refactor month retrieval and add new function for easier caching

src/wp-admin/includes/media.php

@@ -2869,12 +2869,11 @@ function media_upload_library_form( $errors ) {
 
 	<div class="alignleft actions">
 		<?php
-		$months = $wpdb->get_results(
-			"SELECT DISTINCT YEAR( post_date ) AS year, MONTH( post_date ) AS month
-			FROM $wpdb->posts
-			WHERE post_type = 'attachment'
-			ORDER BY post_date DESC"
-		);
+		/** This filter is documented in wp-includes/media.php */
+		$months = apply_filters( 'media_library_months_with_files', null );
+		if ( ! is_array( $months ) ) {
+			$months = wp_get_media_library_attachment_months();
+		}
 
 		$month_count    = count( $months );
 		$selected_month = isset( $_GET['m'] ) ? (int) $_GET['m'] : 0;

src/wp-includes/media.php

@@ -4883,16 +4883,9 @@ function wp_enqueue_media( $args = array() ) {
 	 */
 	$months = apply_filters( 'media_library_months_with_files', null );
 	if ( ! is_array( $months ) ) {
-		$months = $wpdb->get_results(
-			$wpdb->prepare(
-				"SELECT DISTINCT YEAR( post_date ) AS year, MONTH( post_date ) AS month
-				FROM $wpdb->posts
-				WHERE post_type = %s
-				ORDER BY post_date DESC",
-				'attachment'
-			)
-		);
+		$months = wp_get_media_library_attachment_months();
 	}
+
 	foreach ( $months as $month_year ) {
 		$month_year->text = sprintf(
 			/* translators: 1: Month, 2: Year. */
@@ -5152,6 +5145,37 @@ function wp_enqueue_media( $args = array() ) {
 	do_action( 'wp_enqueue_media' );
 }
 
+/**
+ * Retrieves the months that have media library attachments.
+ *
+ * Example:
+ *
+ *     $months = wp_get_media_library_attachment_months();
+ *     $months === array(
+ *         (object) array( 'year' => '2025', 'month' => '2' ),
+ *         (object) array( 'year' => '2024', 'month' => '11' ),
+ *     );
+ *
+ * @since tbd
+ *
+ * @global wpdb $wpdb WordPress database abstraction object.
+ *
+ * @return array<int, object{year: string, month: string}> Months with associated attachment post dates.
+ */
+function wp_get_media_library_attachment_months(): array {
+	global $wpdb;
+
+	return $wpdb->get_results(
+		$wpdb->prepare(
+			"SELECT DISTINCT YEAR( post_date ) AS year, MONTH( post_date ) AS month
+				FROM $wpdb->posts
+				WHERE post_type = %s
+				ORDER BY post_date DESC",
+			'attachment'
+		)
+	);
+}
+
 /**
  * Retrieves media attached to the passed post.
  *

tests/phpunit/tests/media/wpGetMediaLibraryAttachmentMonths.php

@@ -0,0 +1,38 @@
+<?php
+
+/**
+ * Tests for the `wp_get_media_library_attachment_months()` function.
+ *
+ * @group media
+ * @covers ::wp_get_media_library_attachment_months
+ */
+class Tests_Media_wpGetMediaLibraryAttachmentMonths extends WP_UnitTestCase {
+
+	/**
+	 * Tests that the function returns the correct months.
+	 *
+	 * @ticket 63279
+	 */
+	public function test_returns_months() {
+		self::factory()->post->create(
+			array(
+				'post_type' => 'attachment',
+				'post_date' => '2025-03-15 00:00:00',
+			)
+		);
+		self::factory()->post->create(
+			array(
+				'post_type' => 'attachment',
+				'post_date' => '2024-11-01 00:00:00',
+			)
+		);
+
+		$months = wp_get_media_library_attachment_months();
+
+		$this->assertCount( 2, $months );
+		$this->assertSame( '2025', $months[0]->year );
+		$this->assertSame( '3', $months[0]->month );
+		$this->assertSame( '2024', $months[1]->year );
+		$this->assertSame( '11', $months[1]->month );
+	}
+}