Customize: Account for existing query params in the admin URL when wp_customize_url() adds the theme query param.

Query parameters may be inserted in the initial `customize.php` URL via the `admin_url` and `site_url` filters.

Props xipasduarte, westonruter.
Fixes #63632.


git-svn-id: https://develop.svn.wordpress.org/trunk@60499 602fd350-edb4-49c9-b593-d223f7449a82

Author: westonruter

src/wp-includes/theme.php

@@ -3771,7 +3771,7 @@ function _wp_customize_loader_settings() {
 function wp_customize_url( $stylesheet = '' ) {
 	$url = admin_url( 'customize.php' );
 	if ( $stylesheet ) {
-		$url .= '?theme=' . urlencode( $stylesheet );
+		$url = add_query_arg( 'theme', urlencode( $stylesheet ), $url );
 	}
 	return esc_url( $url );
 }

tests/phpunit/tests/theme/wpTheme.php

@@ -375,6 +375,101 @@ public function test_get_files_nonexistent_theme() {
 		$this->assertEmpty( $files );
 	}
 
+	/**
+	 * Test wp_customize_url with no $stylesheet argument.
+	 *
+	 * @ticket 63632
+	 *
+	 * @covers ::wp_customize_url
+	 */
+	public function test_wp_customize_url_no_stylesheet() {
+		$this->assertSame( esc_url( admin_url( 'customize.php' ) ), wp_customize_url() );
+	}
+
+	/**
+	 * Test wp_customize_url with no query args.
+	 *
+	 * @ticket 63632
+	 *
+	 * @covers ::wp_customize_url
+	 */
+	public function test_wp_customize_url_without_query_args() {
+		$this->assertSame( esc_url( admin_url( 'customize.php?theme=foo' ) ), wp_customize_url( 'foo' ) );
+	}
+
+	/**
+	 * Test wp_customize_url with existing query args.
+	 *
+	 * @ticket 63632
+	 *
+	 * @covers ::wp_customize_url
+	 */
+	public function test_wp_customize_url_with_existing_query_args() {
+		$clean_admin_url = admin_url( 'customize.php' );
+
+		// Ensure the existing query arg is present in the URL.
+		add_filter(
+			'admin_url',
+			function ( $url ) {
+				return add_query_arg( 'existing_arg', 'value', $url );
+			}
+		);
+		$this->assertSame( esc_url( $clean_admin_url . '?existing_arg=value&theme=foo' ), wp_customize_url( 'foo' ) );
+	}
+
+	/**
+	 * Test wp_customize_url with existing theme query arg.
+	 *
+	 * @ticket 63632
+	 *
+	 * @covers ::wp_customize_url
+	 */
+	public function test_wp_customize_url_with_existing_theme_query_arg() {
+		$clean_admin_url = admin_url( 'customize.php' );
+
+		// Ensure the theme query arg is replaced with the new value.
+		add_filter(
+			'admin_url',
+			function ( $url ) {
+				return add_query_arg( 'theme', 'to-be-replaced', $url );
+			}
+		);
+		$this->assertSame( esc_url( $clean_admin_url . '?theme=foo' ), wp_customize_url( 'foo' ) );
+	}
+
+	/**
+	 * Test wp_customize_url with multiple theme query args in array syntax.
+	 *
+	 * @ticket 63632
+	 *
+	 * @covers ::wp_customize_url
+	 */
+	public function test_wp_customize_url_with_multiple_theme_query_args() {
+		$clean_admin_url = admin_url( 'customize.php' );
+
+		// Ensure the theme query arg is replaced with the new value.
+		add_filter(
+			'admin_url',
+			function ( $url ) {
+				return add_query_arg( array( 'theme' => array( 'to-be-replaced-1', 'to-be-replaced-2' ) ), $url );
+			}
+		);
+		$this->assertSame( esc_url( $clean_admin_url . '?theme=foo' ), wp_customize_url( 'foo' ) );
+	}
+
+	/**
+	 * Test wp_customize_url with special characters in the theme name.
+	 *
+	 * @ticket 63632
+	 *
+	 * @covers ::wp_customize_url
+	 */
+	public function test_wp_customize_url_with_special_chars() {
+		$stylesheet = 'foo!@-_ +';
+		$expected   = admin_url( 'customize.php?theme=' . urlencode( $stylesheet ) );
+		$this->assertSame( esc_url( $expected ), wp_customize_url( $stylesheet ) );
+	}
+
 	/**
 	 * Data provider.
 	 *