Fixes type error in /includes/class-acf-data.php

* Updated `_key()` to first verify that the provided key is a string or integer before accessing aliases.
* Updated `get()` to verify the derived key is valid before accessing the data array.

Signed-off-by: mavrokordato <info@wordpress-premium.net>

Author: mavrokordato

includes/class-acf-data.php

@@ -93,7 +93,17 @@ function prop( $name = '', $value = null ) {
 		 * @return  type Description.
 		 */
 		function _key( $name = '' ) {
-			return isset( $this->aliases[ $name ] ) ? $this->aliases[ $name ] : $name;
+			// Check if $name is a valid array key type
+			if (!is_string($name) && !is_int($name)) {
+				return $name;
+			}
+
+			// Check if aliases property is an array and the key exists
+			if (is_array($this->aliases) && isset($this->aliases[$name])) {
+				return $this->aliases[$name];
+			}
+
+			return $name;
 		}
 
 		/**
@@ -139,16 +149,20 @@ function is( $key = '' ) {
 		 * @return  mixed
 		 */
 		function get( $name = false ) {
-
 			// Get all.
 			if ( $name === false ) {
 				return $this->data;
+			}
 
-				// Get specific.
-			} else {
-				$key = $this->_key( $name );
-				return isset( $this->data[ $key ] ) ? $this->data[ $key ] : null;
+			// Get specific.
+			$key = $this->_key( $name );
+
+			// Check if $key is a valid array key type and data exists
+			if ((is_string($key) || is_int($key)) && is_array($this->data) && isset($this->data[$key])) {
+				return $this->data[$key];
 			}
+
+			return null;
 		}
 
 		/**