fix: prevent prompt expiration with invalid expiration date

includes/class-newspack-popups-expiry.php

@@ -37,11 +37,17 @@ public static function revert_expired_to_draft() {
 				'post_type'      => Newspack_Popups::NEWSPACK_POPUPS_CPT,
 				'posts_per_page' => -1,
 				'meta_query'     => [ // phpcs:ignore WordPress.DB.SlowDBQuery.slow_db_query_meta_query
+					'relation' => 'AND',
 					[
 						'key'     => 'expiration_date',
 						'value'   => gmdate( 'Y-m-d H:i:s' ),
 						'compare' => '<=',
 					],
+					[
+						'key'     => 'expiration_date',
+						'compare' => 'REGEXP', // phpcs:ignore WordPressVIPMinimum.Performance.RegexpCompare.compare_compare
+						'value'   => '[0-9]{4}-[0-9]{2}-[0-9]{2} [0-9]{2}:[0-9]{2}:[0-9]{2}',
+					],
 				],
 			]
 		);

tests/test-popups-expiry.php

@@ -76,4 +76,26 @@ public function test_prompt_expiry_transition_post_status() {
 		// Check that the expiration_date meta is now deleted.
 		$this->assertEmpty( get_post_meta( $post_id, 'expiration_date', true ) );
 	}
+
+	/**
+	 * Test invalid expiration_date value.
+	 */
+	public function test_prompt_expiry_invalid_meta() {
+		// Create a post with an invalid expiration date.
+		$post_id = $this->factory->post->create(
+			[
+				'post_type' => Newspack_Popups::NEWSPACK_POPUPS_CPT,
+			]
+		);
+		// Set post expiration date meta - for some reason setting this as 'meta_input' while post status is publish does not work.
+		update_post_meta( $post_id, 'expiration_date', '' );
+
+		$this->assertEquals( 'publish', get_post_status( $post_id ) );
+
+		// This will run in a cron job.
+		Newspack_Popups_Expiry::revert_expired_to_draft();
+
+		// Should not have been reverted to draft.
+		$this->assertEquals( 'publish', get_post_status( $post_id ) );
+	}
 }