"Placeholder IDs must be unique for created elements" after using Lakewalker or tracing many nodes manually

[avarab@…]

1. Use lakewalker to trace a bunch of lakes
2. End up with this data

$ grep "id='-" unique-fail.osm |perl -pe "s/.*id='(.*?)'.*/\$1/"|sort -n|uniq -c|sort -n|tail -n15
      1 -97
      1 -98
      1 -99
      2 -464
      2 -465
      2 -466
      2 -467
      2 -468
      2 -469
      2 -470
      2 -471
      2 -472
      2 -473
      2 -474
      2 -567

The data has a bunch of duplicate ways, e.g.:

  <way id='-567' visible='true'>
    <nd ref='-467' />
    <nd ref='-468' />
    <nd ref='-469' />
    <nd ref='-470' />
    <nd ref='-471' />
    <nd ref='-464' />
    <nd ref='-465' />
    <nd ref='-466' />
    <nd ref='-472' />
    <nd ref='-473' />
    <nd ref='-474' />
    <nd ref='-467' />
    <tag k='source' v='Landsat' />
    <tag k='natural' v='water' />
  </way>
  <way id='-567' visible='true'>
    <nd ref='-467' />
    <nd ref='-468' />
    <nd ref='-469' />
    <nd ref='-470' />
    <nd ref='-471' />
    <nd ref='-464' />
    <nd ref='-465' />
    <nd ref='-466' />
    <nd ref='-472' />
    <nd ref='-473' />
    <nd ref='-474' />
    <nd ref='-467' />
    <tag k='source' v='Landsat' />
    <tag k='natural' v='water' />
  </way>

How do I fix this?

[avarab@…]

A .osm file with a bunch of duplicate objects with negative IDs

[avarab@…]

A version of unique-fail.osm that's been manually fixed up

[RichardB]

Error in OSM file created by JOSM

[RichardB]

I have also had a similar error - this time I was tracing manually using JOSM-tested (2255). Whilst tracing, an error message popped up saying something like "An error has occured - this is always a coding error". I tried to save my edits and it failed saying there were duplicate placeholders. I saved a copy of the code and there were two nodes with id '-83' - and the coordinates were identical. I checked the JOSM editing window and found them - and there were two nodes on the same spot. I deleted one of the node '-83's and both disappeared and this enabled me to upload. See attached excerpt of the original .osm ("JOSM_error - duplicatenode - part.osm") file before removing the duplicated nodes.

[stoecker]

Should be fix in recent update. Reopen if not.