maproulette3: Trying to create challenge fails without obvious reason (due to [out:json][timeout:3600] header)

problems tracked down in https://github.com/maproulette/maproulette3/issues/1892#issuecomment-1360286738 and https://github.com/maproulette/maproulette3/issues/1908

original report below

creating project works fine - https://maproulette.org/admin/project/50406

trying to create challenge fails with

    Unable to save your changes{details}
    Unable to retrieve latest challenge data from server.

I supplied

dead wikipedia tags in Germany

as name and

[out:xml][timeout:3600];
( 
    node(101409102)['wikipedia'='de:Roth (Lahn)'];
    node(1018918855)['wikipedia'='de:Charlottenhof (Passow)'];
    node(117178037)['wikipedia'='de:Brombach (Schmitten)'];
); out meta;

as an overpass query and

dead wikipedia tags in Germany

as description

About this issue

Original URL
State: open
Created 2 years ago
Comments: 17 (4 by maintainers)

Most upvoted comments

I opened a project to collect all the open tickets (and future ones) that have to do with improving the Overpass experience for challenge makers: https://github.com/orgs/maproulette/projects/1

That’s a good project idea… I took a quick look and the code’s parsing of overpass queries does not handle various orderings of the “Settings” statement. And the code adds additional settings when it thinks those are missing, so if the query is misinterpreted the other settings may be injected and essentially corrupts the query.

A few overpass Settings examples and how it influences the settings used in the query sent to overpass:

[out:json]; works fine, and [timeout:X]; works fine (although it is changed to [out:json][timeout:X];)
[out:json][timeout:X] works fine
[out:json]; (space at the front) breaks, resulting in [out:json][timeout:Y]; [out:json];
[out:json][timeout:X]; (whitespace) is broken, resulting in [out:json][timeout:Y]; [out:json][timeout:X];
- Conflicting timeout: X is from the user and timeout Y is from the maproulette settings
[timeout:X][out:json]; is technically broken with the result being [out:json][timeout:X][out:json];
[out:xml]; breaks, resulting in [out:json][timeout:Y];[out:xml];

ljdelight on Jan 5, 2023

I created https://maproulette.org/browse/challenges/37135 with that query but leaving out the top statements:

(
    node(301320843); 
    relation(1168916)['wikipedia'='de:Landwehr (Gemeinde)'];
    relation(1182652); 
    ); out center;

So MapRoulette gets confused by those. We need to make that clearer. I opened a project to collect all the open tickets (and future ones) that have to do with improving the Overpass experience for challenge makers: https://github.com/orgs/maproulette/projects/1

mvexel on Dec 20, 2022