﻿id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc
3906	Objects get lost (missing) after subsequent download	kay_D	team	"Hi.

This behaviour is - to my observation - new to JOSM 2417. It worked for
be before (at least in version 2400 and earlier)

Repository Root: http://josm.openstreetmap.de/svn
Build-Date: 2009-11-09 02:31:34
Last Changed Author: Gubaer
Revision: 2417
Repository UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
URL: http://josm.openstreetmap.de/svn/trunk
Last Changed Date: 2009-11-09 01:03:08 +0100 (Mon, 09 Nov 2009)
Last Changed Rev: 2417

The problem is that objects (e.g. ways) are ""forgotten"" after downloading an additional area. E.g. I work in area 1, change and upload something, then scroll a bit around, download something again. After that, usually some ways are missing (to my observation in the first area), which leads to corrupt data and failing uploads after that. 
The problem may be worse: bogus changes are made and may be uploaded without noticing. So far, I only observed failures though, like this:

{{{
ResponseCode=412, Error Header=<Precondition failed: Cannot update way 42977479: data is invalid.>
}}}

Please see the attached image. The area in question is: http://www.openstreetmap.org/?lat=49.798838&lon=9.949303&zoom=18&layers=B000FTF

(I'm just noticing it, and it may or may not be of relevance: reproducing the error now, I see that again the railroad tracks are affected, they were part of the problem before. That may be just a coincidence or not.)

If the upload problems occur, there's no way to save/restore your edits. You also cannot save and load the data, because collisions will occur when you try to merge the save. I can - if desired - provide an example osm save file.

I would rate the problem critical, but I could work around it by only changing small bits and uploading much more frequently, so if objects are lost during edits, you are losing only small bits of work. So I reduced priority to ""major"".
"	defect	closed	major		Core	latest	duplicate	objects missing inconsistency data integrity	kay_D
