Cast scalar meta values as string

php/context/class-fieldmanager-context-post.php

@@ -310,6 +310,7 @@ protected function add_data( $post_id, $meta_key, $meta_value, $unique = false )
 	 *                                Default empty.
 	 */
 	protected function update_data( $post_id, $meta_key, $meta_value, $data_prev_value = '' ) {
+		$meta_value = $this->sanitize_scalar_value( $meta_value );
 		return update_post_meta( $post_id, $meta_key, $meta_value, $data_prev_value );
 	}
 

php/context/class-fieldmanager-context-quickedit.php

@@ -281,6 +281,7 @@ protected function add_data( $post_id, $meta_key, $meta_value, $unique = false )
 	 *                                Default empty.
 	 */
 	protected function update_data( $post_id, $meta_key, $meta_value, $data_prev_value = '' ) {
+		$meta_value = $this->sanitize_scalar_value( $meta_value );
 		return update_post_meta( $post_id, $meta_key, $meta_value, $data_prev_value );
 	}
 

php/context/class-fieldmanager-context-storable.php

@@ -163,6 +163,23 @@ protected function load_walk_children( $field ) {
 		}
 	}
 
+	/**
+	 * Meta and options are always stored as strings, so it's best to ensure
+	 * that scalar values get cast as strings to ensure that `update_metadata()`
+	 * and `update_option()` are able to correctly compare the current value
+	 * against the previous value.
+	 *
+	 * @param  mixed $value Value being stored.
+	 * @return string|array If $value is scalar, a string is returned. Otherwise,
+	 *                      $value returns untouched.
+	 */
+	public static function sanitize_scalar_value( $value ) {
+		if ( is_scalar( $value ) && ! is_string( $value ) ) {
+			return strval( $value );
+		}
+		return $value;
+	}
+
 	/**
 	 * Method to get data from the context's storage engine.
 	 *

php/context/class-fieldmanager-context-submenu.php

@@ -239,6 +239,7 @@ protected function add_data( $data_id, $option_name, $option_value, $unique = fa
 	 * @return bool Option updated successfully.
 	 */
 	protected function update_data( $data_id, $option_name, $option_value, $option_prev_value = '' ) {
+		$option_value = $this->sanitize_scalar_value( $option_value );
 		return update_option( $option_name, $option_value );
 	}
 

php/context/class-fieldmanager-context-term.php

@@ -384,6 +384,7 @@ protected function add_data( $term_id, $meta_key, $meta_value, $unique = false )
 	 * @param bool   $meta_prev_value The previous meta value.
 	 */
 	protected function update_data( $term_id, $meta_key, $meta_value, $meta_prev_value = '' ) {
+		$meta_value = $this->sanitize_scalar_value( $meta_value );
 		if ( $this->use_fm_meta ) {
 			return fm_update_term_meta( $term_id, $this->current_taxonomy, $meta_key, $meta_value, $meta_prev_value );
 		} else {

php/context/class-fieldmanager-context-user.php

@@ -174,6 +174,7 @@ protected function add_data( $user_id, $meta_key, $meta_value, $unique = false )
 	 * @param mixed  $data_prev_value The previous meta data.
 	 */
 	protected function update_data( $user_id, $meta_key, $meta_value, $data_prev_value = '' ) {
+		$meta_value = $this->sanitize_scalar_value( $meta_value );
 		return call_user_func(
 			/**
 			 * Filters function used to update user meta. This improves compatibility with

tests/php/test-fieldmanager-context-storable.php

@@ -0,0 +1,32 @@
+<?php
+
+/**
+ * Tests the Storable Context base.
+ *
+ * @group context
+ */
+class Test_Fieldmanager_Context_Storable extends WP_UnitTestCase {
+	public function scalar_sanitize_data() {
+		return array(
+			array( 1, '1' ),
+			array( 0, '0' ),
+			array( true, '1' ),
+			array( false, '' ),
+			array( 'abc', 'abc' ),
+			array( array(), array() ),
+			array( array( 1, 2, 3 ), array( 1, 2, 3 ) ),
+			array( 1.234, '1.234' ),
+			array( null, null ),
+			array( '', '' ),
+		);
+	}
+
+	/**
+	 * @dataProvider scalar_sanitize_data
+	 * @param  mixed $test     Test cases.
+	 * @param  mixed $expected Expected values.
+	 */
+	public function test_sanitize_scalar_values( $test, $expected ) {
+		$this->assertSame( $expected, \Fieldmanager_Context_Post::sanitize_scalar_value( $test ) );
+	}
+}