"Join selected nodes" adds an extraneous node when joining near-duplicate nodes

[Anonymous Reporter]

(bug is happening on 0.48+devel r9640)

The attached file is an open path, with end nodes at identical or almost-identical coordinates. When you select those end nodes and click "Join selected nodes", the nodes are merged and the path is closed as they should be but an extra node appears at the same position as the top node. Also, the direction of the arrow is vertical when it should be horizontal.

The bug does not occur if you ungroup 'layer1' (which has transform=translate(...)), suggesting round-off errors have an impact.

[Anonymous Reporter (isbugz)]

Also, if you make the node to the right of the duplicate nodes smooth, the bug does not occur.

[Krzysztof Kosinski (tweenk)]

This is a different manifestation of bug #515237 "Rotate shape adds node". It is caused by imprecisions in storing the last segment, and not specifically related to node join.