TIGER tags changed unnecessarily with Combine Way and Replace Geometry

[rickmastfan67]

I've just started noticing this while cleaning up some Tiger imported ways here in the USA. Sometimes when nodes that aren't needed in the beginning of the way are moved to a different place in the way to keep them, one of the tags on the way gets changed without warning. The tag in question is "tiger:tlid".

I've created a test file that shows this in action (will be attached below). Hopefully, nobody edits this way till you can test this it because it requires the History of the way not to be altered after I created the file.

Here's the ways to use the file to duplicate this problem (once you open the file):

1. Select the blank way and the "Hamilton Rd" way that parallels it.
2. Once you have both selected, do the "Replace Geometry" action.
3. Once that has been completed, pull up the history (Ctrl+H - hopefully no shortcut conflict on your end) on "Hamilton Rd".

Once you've done that, notice on the history window that the "tiger:tlid" tag has been changed without any warning.

Have no idea why in the first place it's getting changed. This is only happening when a node gets moved later in the line. If all the nodes stay in the same place, the "tiger:tlid" tag doesn't get changed at all when using the "Replace Geometry".

[rickmastfan67]

Whoops, forgot the build info:

Repository Root: http://josm.openstreetmap.de/svn
Build-Date: 2012-02-17 02:32:15
Last Changed Author: stoecker
Revision: 4961
Repository UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
URL: http://josm.openstreetmap.de/svn/trunk
Last Changed Date: 2012-02-16 21:21:17 +0100 (Thu, 16 Feb 2012)
Last Changed Rev: 4961

Identification: JOSM/1.5 (4961 en)
Memory Usage: 308 MB / 2730 MB (118 MB allocated, but free)
Java version: 1.6.0_31, Sun Microsystems Inc., Java HotSpot(TM) 64-Bit Server VM
Operating system: Windows 7
Dataset consistency test: No problems found

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Plugin: measurement (27464)
Plugin: openstreetbugs (27355)
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Plugin: turnrestrictions (27676)
Plugin: undelete (27649)
Plugin: utilsplugin2 (27761)

[joshdoe]

I believe this to actually be a problem in core, specifically TigerUtils.combineTags​. Note the same issue occurs if you combine a new untagged way with this same road. The tlid values are the same, the order is just changed. The order is changed because a Set is used, which doesn't guarantee an order, but guarantees there won't be any duplicates (which is why a Set is used in the first place). I believe a simple fix would be to only combine tags if there's more than one value.

Thankfully this problem isn't serious, it just adds to the noise of a changeset. It's worth fixing however.

[Don-vip]

In 5569/josm:

fix #7405 - TIGER tags sometimes changed unnecessarily when combined

[Don-vip]

@joshdoe: thanks for the problem investigation !