Ajax: Protect against exceptions thrown synchronously by xhr.send

jaubourg · jaubourg · commit 01c360f96390 · 2014-01-29T14:18:58.000+01:00
When xhr.send throws an exception synchronously, the onerror handler may have
been called already which, unchecked, makes the exception bubble up outside of
jQuery.ajax.

We now catch the exception pre-emptively and only rethrow if we know it hasn't
already been notified through the onerror handler.

Fixes #14683
diff --git a/src/ajax/xhr.js b/src/ajax/xhr.js
@@ -112,10 +112,15 @@ jQuery.ajaxTransport(function( options ) {
 				// Create the abort callback
 				callback = xhrCallbacks[ id ] = callback("abort");
 
-				// Do send the request
-				// This may raise an exception which is actually
-				// handled in jQuery.ajax (so no try/catch here)
-				xhr.send( options.hasContent && options.data || null );
+				try {
+					// Do send the request (this may raise an exception)
+					xhr.send( options.hasContent && options.data || null );
+				} catch ( e ) {
+					// #14683: Only rethrow if this hasn't been notified as an error yet
+					if ( callback ) {
+						throw e;
+					}
+				}
 			},
 
 			abort: function() {
diff --git a/test/unit/ajax.js b/test/unit/ajax.js
@@ -1544,6 +1544,36 @@ module( "ajax", {
 		});
 	}
 
+	ajaxTest( "#14683 - jQuery.ajax() - Exceptions thrown synchronously by xhr.send should be caught", 4, [
+		{
+			url: "data/params_html.php",
+			method: "POST",
+			data: {
+				toString: function() {
+					throw "Can't parse";
+				}
+			},
+			processData: false,
+			done: function( data ) {
+				ok( false, "done: " + data );
+			},
+			fail: function( jqXHR, status, error ) {
+				ok( true, "exception caught: " + error );
+				strictEqual( jqXHR.status, 0, "proper status code" );
+				strictEqual( status, "error", "proper status" );
+			}
+		},
+		{
+			url: "http://domain.org:80d",
+			done: function( data ) {
+				ok( false, "done: " + data );
+			},
+			fail: function( _, status, error ) {
+				ok( true, "fail: " + status + " - " + error );
+			}
+		}
+	]);
+
 //----------- jQuery.ajaxPrefilter()
 
 	ajaxTest( "jQuery.ajaxPrefilter() - abort", 1, {
