From ee9687d441d625a420dc65590bbd0b930f800b3f Mon Sep 17 00:00:00 2001
From: James Huston <james@jameshuston.net>
Date: Tue, 16 Oct 2012 14:51:54 -0400
Subject: [PATCH] Fix #12751. Ensure parseJson throws in the same situations as
 JSON.parse. Close gh-993.

---
 AUTHORS.txt       |  3 ++-
 src/core.js       | 35 ++++++++++++++++-------------
 test/unit/ajax.js | 14 ++++++++++++
 test/unit/core.js | 57 ++++++++++++++++++++++++++++++++++++++++++++---
 4 files changed, 90 insertions(+), 19 deletions(-)

diff --git a/AUTHORS.txt b/AUTHORS.txt
index 5a213d5a2..b2dd8bfab 100644
--- a/AUTHORS.txt
+++ b/AUTHORS.txt
@@ -133,4 +133,5 @@ Daniel Chatfield <chatfielddaniel@gmail.com>
 Nikita Govorov <nikita.govorov@gmail.com>
 Michael Pennisi <mike@mikepennisi.com>
 Markus Staab <markus.staab@redaxo.de>
-Daniel Gálvez <dgalvez@editablething.com>
\ No newline at end of file
+Daniel Gálvez <dgalvez@editablething.com>
+James Huston <james@jameshuston.net>
\ No newline at end of file
diff --git a/src/core.js b/src/core.js
index 5564a9870..2f5908b55 100644
--- a/src/core.js
+++ b/src/core.js
@@ -488,27 +488,32 @@ jQuery.extend({
 	},
 
 	parseJSON: function( data ) {
-		if ( !data || typeof data !== "string") {
-			return null;
-		}
-
-		// Make sure leading/trailing whitespace is removed (IE can't handle it)
-		data = jQuery.trim( data );
-
 		// Attempt to parse using the native JSON parser first
 		if ( window.JSON && window.JSON.parse ) {
 			return window.JSON.parse( data );
 		}
 
-		// Make sure the incoming data is actual JSON
-		// Logic borrowed from http://json.org/json2.js
-		if ( rvalidchars.test( data.replace( rvalidescape, "@" )
-			.replace( rvalidtokens, "]" )
-			.replace( rvalidbraces, "")) ) {
-
-			return ( new Function( "return " + data ) )();
-
+		if ( data === null ) {
+			return data;
 		}
+
+		if ( typeof data === "string" ) {
+			
+			// Make sure leading/trailing whitespace is removed (IE can't handle it)
+			data = jQuery.trim( data );
+
+			if ( data ) {
+				// Make sure the incoming data is actual JSON
+				// Logic borrowed from http://json.org/json2.js
+				if ( rvalidchars.test( data.replace( rvalidescape, "@" )
+					.replace( rvalidtokens, "]" )
+					.replace( rvalidbraces, "")) ) {
+
+					return ( new Function( "return " + data ) )();
+				}
+			}
+		}
+
 		jQuery.error( "Invalid JSON: " + data );
 	},
 
diff --git a/test/unit/ajax.js b/test/unit/ajax.js
index 4a93c65fe..c5185efb3 100644
--- a/test/unit/ajax.js
+++ b/test/unit/ajax.js
@@ -2759,4 +2759,18 @@ if ( jQuery.ajax && ( !isLocal || hasPHP ) ) {
 			start();
 		});
 	});
+	
+	test( "jQuery.ajax - empty json gets to error callback instead of success callback.", function() {
+		expect( 1 );
+
+		stop();
+
+		jQuery.ajax( url("data/echoData.php"), {
+			error: function( _, __, error ) {
+				equal( typeof error === "object", true,  "Didn't get back error object for empty json response" );
+				start();
+			},
+			dataType: "json"
+		});
+	});
 }
diff --git a/test/unit/core.js b/test/unit/core.js
index c0a719fe3..85d394e98 100644
--- a/test/unit/core.js
+++ b/test/unit/core.js
@@ -1150,9 +1150,13 @@ test("jQuery.parseHTML", function() {
 test("jQuery.parseJSON", function(){
 	expect(8);
 
-	equal( jQuery.parseJSON(), null, "Nothing in, null out." );
-	equal( jQuery.parseJSON( null ), null, "Nothing in, null out." );
-	equal( jQuery.parseJSON( "" ), null, "Nothing in, null out." );
+	raises(function() {
+		jQuery.parseJSON();
+	}, null, "parseJson now matches JSON.parse for empty input." );
+	equal(jQuery.parseJSON( null ), null, "parseJson now matches JSON.parse on null input." );
+	raises( function() {
+		jQuery.parseJSON( "" );
+	}, null, "parseJson now matches JSON.parse for empty strings." );
 
 	deepEqual( jQuery.parseJSON("{}"), {}, "Plain object parsing." );
 	deepEqual( jQuery.parseJSON("{\"test\":1}"), {"test":1}, "Plain object parsing." );
@@ -1346,3 +1350,50 @@ test("jQuery.camelCase()", function() {
 		equal( jQuery.camelCase( key ), val, "Converts: " + key + " => " + val );
 	});
 });
+
+test( "JQuery.parseJSON() test internal parseJson (using fallback) to make sure that it throws like JSON.parse", function() {
+	expect( 10 );
+
+	var jsonParse = window.JSON;
+	window.JSON = null;
+
+	raises(function() {
+		jsonParse.parse("''");
+	});
+
+	raises(function() {
+		jQuery.parseJSON("''");
+	});
+
+	raises(function() {
+		jsonParse.parse("");
+	});
+
+	raises(function() {
+		jQuery.parseJSON("");
+	});
+
+	raises(function() {
+		jsonParse.parse({});
+	});
+
+	raises(function() {
+		jQuery.parseJSON({});
+	});
+
+	var parsedValue = jsonParse.parse(null);
+	equal( parsedValue, null );
+
+	parsedValue = jQuery.parseJSON(null);
+	equal( parsedValue, null );
+
+	parsedValue = jsonParse.parse("{}");
+	equal( (typeof parsedValue === "object"), true );
+
+	parsedValue = jQuery.parseJSON("{}");
+	equal( (typeof parsedValue === "object"), true );
+	
+
+	window.JSON = jsonParse;
+} );
+