Error with recursive function calls in the instrumented JavaScript code #62

gantony · 2020-04-19T23:04:23Z

First, congrats on creating BLeak, this is such a wonderful and helpful software :)

I ran into an issue when using recursive function calls in the instrumented JavaScript code.

The issue is with an old version of the jQuery (haven't checked a newer version).

The original code causing the issue is:

    add: function() {
        if ( list ) {

            // If we have memory from a past run, we should fire after adding
            if ( memory && !firing ) {
                firingIndex = list.length - 1;
                queue.push( memory );
            }

            ( function add( args ) {
                jQuery.each( args, function( _, arg ) {
                    if ( jQuery.isFunction( arg ) ) {
                        if ( !options.unique || !self.has( arg ) ) {
                            list.push( arg );
                        }
                    } else if ( arg && arg.length && jQuery.type( arg ) !== "string" ) {

                        // Inspect recursively
                        // !!! This is where the error happens !!! 
                        add( arg );
                    }
                } );
            } )( arguments );

            if ( memory && !firing ) {
                fire();
            }
        }
        return this;
    },

The instrumented code is as follows:

s31.self = {
      add: $$$FUNCTION_EXPRESSION$$$(function () {
        if (s31.list) {
          if (s31.memory && !s31.firing) {
            s31.firingIndex = s31.list.length - 1;
            s31.queue.push(s31.memory);
          }
          $$$FUNCTION_EXPRESSION$$$(function add(args) {
            var s32 = $$$CREATE_SCOPE_OBJECT$$$(s31, ["add"], {}, [], []);
            s1.jQuery.each(args, $$$FUNCTION_EXPRESSION$$$(function (_, arg) {
              if (s1.jQuery.isFunction(arg)) {
                if (!s31.options.unique || !s31.self.has(arg)) {
                  s31.list.push(arg);
                }
              } else if (arg && arg.length && !$$$SEQ$$$(s1.jQuery.type(arg), "string")) {
                // !!! This is where the error happens !!!
                (s32.add || s32.add)(arg);
              }
            }, s32));
          }, s31)(arguments);
          if (s31.memory && !s31.firing) {
            (s31.fire || s31.fire)();
          }
        }
        return this;
      }, s31),

I was able to work around the issue by rewriting the function so that the instrumented code becomes:

s31.self = {
      add: $$$FUNCTION_EXPRESSION$$$(function () {
        var s32 = $$$CREATE_SCOPE_OBJECT$$$(s31, ["add2", "callAdd2"], {}, [], []);
        if (s31.list) {
          if (s31.memory && !s31.firing) {
            s31.firingIndex = s31.list.length - 1;
            s31.queue.push(s31.memory);
          }
          s32.add2 = $$$FUNCTION_EXPRESSION$$$(function (args) {
            s1.jQuery.each(args, $$$FUNCTION_EXPRESSION$$$(function (_, arg) {
              if (s1.jQuery.isFunction(arg)) {
                if (!s31.options.unique || !s31.self.has(arg)) {
                  s31.list.push(arg);
                }
              } else if (arg && arg.length && !$$$SEQ$$$(s1.jQuery.type(arg), "string")) {
                (s32.callAdd2 || s32.callAdd2)(arg);
              }
            }, s32));
          }, s32);
          s32.callAdd2 = $$$FUNCTION_EXPRESSION$$$(function (args) {
            (s32.add2 || s32.add2)(args);
          }, s32);
          (s32.add2 || s32.add2)(arguments);
          if (s31.memory && !s31.firing) {
            (s31.fire || s31.fire)();
          }
        }
        return this;
      }, s31),

This is not blocking me anymore, but other people may run into similar issues.

Please let me know if I can provide anything else to help solve this issue.

gantony · 2020-04-19T23:15:14Z

I can actually reduce this to a somewhat more minimal example if that helps:

recursive-function.html

<html>

<body>
    <button id="addToList">addToList()</button>

    <script src="./recursive-function.js"></script>
</body>
</html>

recursive-function.js

var list = [];

function isWindow( obj ) {
    return obj != null && obj === obj.window;
}
function isArrayLike( obj ) {

	// Support: iOS 8.2 (not reproducible in simulator)
	// `in` check used to prevent JIT error (gh-2145)
	// hasOwn isn't used here due to false negatives
	// regarding Nodelist length in IE
	var length = !!obj && "length" in obj && obj.length,
		type = typeof obj;

	if ( type === "function" || isWindow( obj ) ) {
		return false;
	}

	return type === "array" || length === 0 ||
		typeof length === "number" && length > 0 && ( length - 1 ) in obj;
}

var jQueryEach = function(obj, callback) {
		var length, i = 0;

		if ( isArrayLike( obj ) ) {
			length = obj.length;
			for ( ; i < length; i++ ) {
				if ( callback.call( obj[ i ], i, obj[ i ] ) === false ) {
					break;
				}
			}
		} else {
			for ( i in obj ) {
				if ( callback.call( obj[ i ], i, obj[ i ] ) === false ) {
					break;
				}
			}
		}

		return obj;
}
var add = function() {
    ( function innerAdd( args ) {
        jQueryEach( args, function( _, arg ) {
            if ( typeof arg === "function" ) {
                list.push( arg );
            } else if ( arg && arg.length && typeof arg !== "string" ) {
                // Inspect recursively
                innerAdd( arg );
            }
        });
    } )( arguments );
};

function addToList() {
    
    // Please don't ask why I'm doing this, it's coming from another library initialising...
    var crazyArgs = {
        0: undefined,
        1: {
            0: undefined,
            length: 1
        },
        length: 2
    }
    add(crazyArgs);
    console.log("list: ", list);
}

document.getElementById('addToList').addEventListener('click', addToList);

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Error with recursive function calls in the instrumented JavaScript code #62

Error with recursive function calls in the instrumented JavaScript code #62

gantony commented Apr 19, 2020

gantony commented Apr 19, 2020

Error with recursive function calls in the instrumented JavaScript code #62

Error with recursive function calls in the instrumented JavaScript code #62

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gantony commented Apr 19, 2020

gantony commented Apr 19, 2020