Core: Report browser errors in parseXML

Fixes gh-4784
Closes gh-4816

Author: mgol

src/core/parseXML.js

@@ -2,7 +2,7 @@ import jQuery from "../core.js";
 
 // Cross-browser xml parsing
 jQuery.parseXML = function( data ) {
-	var xml;
+	var xml, parserErrorElem;
 	if ( !data || typeof data !== "string" ) {
 		return null;
 	}
@@ -11,12 +11,17 @@ jQuery.parseXML = function( data ) {
 	// IE throws on parseFromString with invalid input.
 	try {
 		xml = ( new window.DOMParser() ).parseFromString( data, "text/xml" );
-	} catch ( e ) {
-		xml = undefined;
-	}
+	} catch ( e ) {}
 
-	if ( !xml || xml.getElementsByTagName( "parsererror" ).length ) {
-		jQuery.error( "Invalid XML: " + data );
+	parserErrorElem = xml && xml.getElementsByTagName( "parsererror" )[ 0 ];
+	if ( !xml || parserErrorElem ) {
+		jQuery.error( "Invalid XML: " + (
+			parserErrorElem ?
+				jQuery.map( parserErrorElem.childNodes, function( el ) {
+					return el.textContent;
+				} ).join( "\n" ) :
+				data
+		) );
 	}
 	return xml;
 };

test/unit/core.js

@@ -1418,9 +1418,9 @@ QUnit.test( "jQuery.parseXML", function( assert ) {
 	}
 	try {
 		xml = jQuery.parseXML( "<p>Not a <<b>well-formed</b> xml string</p>" );
-		assert.ok( false, "invalid xml not detected" );
+		assert.ok( false, "invalid XML not detected" );
 	} catch ( e ) {
-		assert.strictEqual( e.message, "Invalid XML: <p>Not a <<b>well-formed</b> xml string</p>", "invalid xml detected" );
+		assert.ok( e.message.indexOf( "Invalid XML:" ) === 0, "invalid XML detected" );
 	}
 	try {
 		xml = jQuery.parseXML( "" );
@@ -1436,6 +1436,29 @@ QUnit.test( "jQuery.parseXML", function( assert ) {
 	}
 } );
 
+// Support: IE 11+
+// IE throws an error when parsing invalid XML instead of reporting the error
+// in a `parsererror` element, skip the test there.
+QUnit.testUnlessIE( "jQuery.parseXML - error reporting", function( assert ) {
+	assert.expect( 2 );
+
+	var errorArg, lineMatch, line, columnMatch, column;
+
+	sinon.stub( jQuery, "error" );
+
+	jQuery.parseXML( "<p>Not a <<b>well-formed</b> xml string</p>" );
+	errorArg = jQuery.error.firstCall.lastArg.toLowerCase();
+	console.log( "errorArg", errorArg );
+
+	lineMatch = errorArg.match( /line\s*(?:number)?\s*(\d+)/ );
+	line = lineMatch && lineMatch[ 1 ];
+	columnMatch = errorArg.match( /column\s*(\d+)/ );
+	column = columnMatch && columnMatch[ 1 ];
+
+	assert.strictEqual( line, "1", "reports error line" );
+	assert.strictEqual( column, "11", "reports error column" );
+} );
+
 testIframe(
 	"document ready when jQuery loaded asynchronously (#13655)",
 	"core/dynamic_ready.html",