From 5ea3c91d57c17fdadbd0ef910b65c4ff8891ff87 Mon Sep 17 00:00:00 2001
From: James Nylen <jnylen0@git.wordpress.org>
Date: Mon, 22 May 2017 16:15:25 +0000
Subject: [PATCH] REST API: Fix changing parameters with `set_param()` for some
 requests.

Prior to this commit, `WP_Rest_Request::get_param()` traversed through the parameter order but `WP_Rest_Request::set_param()` did not. For JSON requests (and likely other situations as well), this meant that changing a parameter with `set_param()` would have no effect on `get_param()`.

Props TimothyBlynJacobs.
Fixes #40344.



git-svn-id: https://develop.svn.wordpress.org/trunk@40815 602fd350-edb4-49c9-b593-d223f7449a82
---
 .../rest-api/class-wp-rest-request.php        | 17 +++++-------
 tests/phpunit/tests/rest-api/rest-request.php | 27 +++++++++++++++++++
 2 files changed, 34 insertions(+), 10 deletions(-)

diff --git a/src/wp-includes/rest-api/class-wp-rest-request.php b/src/wp-includes/rest-api/class-wp-rest-request.php
index 0a26d0fe3d..e41c014557 100644
--- a/src/wp-includes/rest-api/class-wp-rest-request.php
+++ b/src/wp-includes/rest-api/class-wp-rest-request.php
@@ -354,7 +354,11 @@ class WP_REST_Request implements ArrayAccess {
 	 */
 	protected function get_parameter_order() {
 		$order = array();
-		$order[] = 'JSON';
+
+		$content_type = $this->get_content_type();
+		if ( $content_type['value'] === 'application/json' ) {
+			$order[] = 'JSON';
+		}
 
 		$this->parse_json_params();
 
@@ -424,15 +428,8 @@ class WP_REST_Request implements ArrayAccess {
 	 * @param mixed  $value Parameter value.
 	 */
 	public function set_param( $key, $value ) {
-		switch ( $this->method ) {
-			case 'POST':
-				$this->params['POST'][ $key ] = $value;
-				break;
-
-			default:
-				$this->params['GET'][ $key ] = $value;
-				break;
-		}
+		$order = $this->get_parameter_order();
+		$this->params[ $order[0] ][ $key ] = $value;
 	}
 
 	/**
diff --git a/tests/phpunit/tests/rest-api/rest-request.php b/tests/phpunit/tests/rest-api/rest-request.php
index db876bdb79..b7f043d6e7 100644
--- a/tests/phpunit/tests/rest-api/rest-request.php
+++ b/tests/phpunit/tests/rest-api/rest-request.php
@@ -580,4 +580,31 @@ class Tests_REST_Request extends WP_UnitTestCase {
 		$request = WP_REST_Request::from_url( $using_home );
 		$this->assertFalse( $request );
 	}
+
+	public function test_set_param() {
+		$request = new WP_REST_Request();
+		$request->set_param( 'param', 'value' );
+		$this->assertEquals( 'value', $request->get_param( 'param' ) );
+	}
+
+	public function test_set_param_follows_parameter_order() {
+		$request = new WP_REST_Request();
+		$request->add_header( 'content-type', 'application/json' );
+		$request->set_method( 'POST' );
+		$request->set_body( wp_json_encode( array(
+			'param' => 'value'
+		) ) );
+		$this->assertEquals( 'value', $request->get_param( 'param' ) );
+		$this->assertEquals(
+			array( 'param' => 'value' ),
+			$request->get_json_params()
+		);
+
+		$request->set_param( 'param', 'new_value' );
+		$this->assertEquals( 'new_value', $request->get_param( 'param' ) );
+		$this->assertEquals(
+			array( 'param' => 'new_value' ),
+			$request->get_json_params()
+		);
+	}
 }