"create parallel way" tool creates zero-length ways when clicked several times

[openstreetmap-trac]

Reporter: aseerel4c26
[Submitted to the original trac issue database at 10.07am, Monday, 30th December 2013]

(based on [https://help.openstreetmap.org/questions/29395/potlatch-2-wont-save-precondition-failed-cannot-create-way-data-is-invalid jc86035's report] at help.osm.org.)

test case:

1. Create a way/click on an existing way.

2. Press the "Create parallel way (P)" button in the toolbox several times.
   

3. Click anywhere on the map.
   

4. There will now be a large amount of ways with no nodes (which you will not see).
   

5. Press the Save button, and the error dialog box ("Precondition failed: Cannot create way: data is invalid") will pop up.

I (first created a new two-node way) clicked 5 times on it and had 5 ways without any node (visible in the data).