Intersection is wrongly empty

[ksesong]

Description/Steps to reproduce

var pathA = PathItem.create("M0,0h60v60h-60z");
var pathB = PathItem.create("M60,47c-0.89493,-0.00177 -1.72254,0.47497 -2.17,1.25l-12.12,21c-0.44703,0.77427 -0.44656,1.72831 0.00123,2.50214c0.44779,0.77383 1.27472,1.24963 2.16877,1.24786h24.24c0.89405,0.00177 1.72098,-0.47403 2.16877,-1.24786c0.44779,-0.77383 0.44826,-1.72787 0.00123,-2.50214l-12.12,-21c-0.44746,-0.77503 -1.27507,-1.25177 -2.17,-1.25M64.33,47l12.12,21c0.89315,1.54699 0.89316,3.45295 0.00003,4.99995c-0.89313,1.547 -2.54373,2.50001 -4.33003,2.50005h-24.24c-1.78631,-0.00005 -3.4369,-0.95306 -4.33003,-2.50005c-0.89313,-1.547 -0.89312,-3.45296 0.00003,-4.99995l12.12,-21c0.88236,-1.55771 2.53981,-2.51466 4.33,-2.5c1.79019,-0.01466 3.44764,0.94229 4.33,2.5z");
pathA.fillColor = 'red';
pathB.fillColor = 'blue';
var interesectAB = pathA.intersect(pathB);
interesectAB.fillColor = 'green';
console.log(interesectAB.pathData)

There is no "green" path (which would identify the interesection).

Link to reproduction test-case

http://sketch.paperjs.org/#V/0.11.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

Expected result

Strangely enough, when I move the square just a little, the intersection appears.

http://sketch.paperjs.org/#V/0.11.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

Similarly, same issue in this situation (you can move the rectangle a little bit, and the intersections become correct):

http://sketch.paperjs.org/#V/0.11.8/S/bVHRTsIwFP2VpS9gUpZ2q2WB+ND45IOJiW9YH8q4OEK3YikYNf67vVsBNeYud9s55562p5+kMy2QGXncQqgbQkntVvivO6yj8dnrwfgAPrvJHkxo7gK0ee3BBBhrcs8oayQ7StZMJPvQ5Go+DO2iVP0/Ihktq1yogueS9o1RHgtBGsmfODJJj3NTobig8UGcUSGRPCFYvaZlk7JShaDFSVgNxglJwlIu2tivc6k4rsYvW5niJ1rHN0/9vBkkF8NJ+1Pm6421t846jGi0tAcYzTG7lNsvWpMXD9BpkmLadFGxhzpgVoPbGRonA1zoovtj9w7WurfeL97dMoa83bmo3pPZ0/PXNw==

[lehni]

This can be reduced to this sketch. It looks like one intersection isn't found!

[lehni]

Possibly related is this scenario, where two intersections are found, but one is falsely assumed to not be a crossing.

[lehni]

Ok, this happens because the first path in the compound path is lacking the close command. Simply add a z there, and it works:

http://sketch.paperjs.org/#V/0.11.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

But this is a bug... When a path or compound path is filled, we should add the closing lines between the first and last segment to the curves.