'Move node into way' can sometimes result in multiple duplicate nodes

[rickmastfan67]

Steps to reproduce:

1. Download attached *.osm file.
2. Activate the 'select' tool and draw a box over the intersection in the attached file.
3. Hit 'n' twice to 'Move Node into Way'.

What happens:
If you select the left hand 'primary' highway and look at the history, you see multiple duplicate nodes in the way now.

What should happen:
JOSM shouldn't allow you to hit 'n' more than once on a section unless you change part of it. It should also somehow refuse anyways because of the 3 duplicate nodes right there.

Repository Root: http://josm.openstreetmap.de/svn
Build-Date: 2015-02-11 02:34:32
Last Changed Author: Klumbumbus
Revision: 8045
Repository UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Relative URL: ^/trunk
URL: http://josm.openstreetmap.de/svn/trunk
Last Changed Date: 2015-02-11 00:55:31 +0100 (Wed, 11 Feb 2015)
Last Changed Rev: 8045

Identification: JOSM/1.5 (8045 en) Windows 7 64-Bit
Memory Usage: 361 MB / 1820 MB (96 MB allocated, but free)
Java version: 1.7.0_71, Oracle Corporation, Java HotSpot(TM) 64-Bit Server VM
Dataset consistency test: No problems found

Plugins:
- ImageryCache (30892)
- OpeningHoursEditor (30962)
- buildings_tools (30955)
- measurement (30892)
- mirrored_download (30962)
- notes (v0.9.5)
- osmarender (30892)
- reverter (30953)
- turnrestrictions (30962)
- undelete (30892)
- utilsplugin2 (30958)

[mdk]

I think the problem is more general. "Move Node onto Way" behaves strange, if more then one node is selected.

In this example we start with an illegal state:

• Errors (1)
  • Highway duplicated nodes - Duplicated nodes (1)
• Warnings (10)
  • Way end node near other highway (2)
  • Crossing ways (5)

Already the first move operation ('N') cause

• Errors (1)
  • Highway duplicated nodes - Duplicated nodes (1)
• Warnings (11)
  • Overlapping highways (1)
  • Crossing ways (7)

The second move operation produces

• Errors (2)
  • Way contains segment twice (1)
  • Highway duplicated nodes - Duplicated nodes (1)
• Warnings (18)
  • Overlapping highways (3)
  • Self-intersecting ways (3)
  • Crossing ways (9)

And the third move operation results in

• Errors (4)
  • Way contains segment twice (3)
  • Highway duplicated nodes - Duplicated nodes (1)
• Warnings (15)
  • Self-intersecting ways (3)
  • Crossing ways (9)

"Move Node onto Way" do unexpected things, if more than one node is selected.

Load attached ticket11099_2.osm select the 4 nodes of the footway and press 'N'.

Something like this should happens: The selected nodes are processed one after the other. The actual processed node chooses a way to be moved on (the nearest way?), then he's moved onto this way and joined to the way.
In this case, the 4 footway nodes should be in line with the unclassified highway. But instead the unclassified highway follows a "zig-zag". And even worst, if you undo the operation, change the zoom factor, and execute "Move Node onto Way" again, you get a completely different result.