JOSM is out of memory - While adding a local xml preset

[HeinerSchaefer]

I built a preset to edit trees and tree rows in OSM.
It's working fine so far.

The I've done some changes and got the following error message:

JOSM is out of memory. Strange things may happen. ...

I started trouble shooting by deleting blocks.
The original preset has more than 2000 lines.
Now I have a preset with 81 lines and the error.
And I don't know why!

This issue happens on two installations, one Ubuntu, one Debian.
JOSM Version: 17428
Java-Version 11.0.10

[HeinerSchaefer]

Very short version of the preset. Memory Error should come up.

[HeinerSchaefer]

Much longer preset, not for tree rows, but for trees. No error here.

[GerdP]

This part looks like a recursive definition. tree-row-keys -> tree-row-keys

    <chunk id="tree-row-keys">
        <reference ref="tree-row-keys" />
        <text key="name" text="Name" />
        <text key="height" text="Height (meters)" />
        <text key="start_date" text="Start date" />
    </chunk>

Not sure if that's correct but it might trigger such a memory problem.

[HeinerSchaefer]

This is the fixed part:

    <chunk id="tree-row-keys">
        <key key="natural" value="tree_row" />
        <text key="name" text="Name" />
        <text key="height" text="Height (meters)" />
        <text key="start_date" text="Start date" />
    </chunk>

This chunk was called recursive.
Copy-Paste-Problem!

[GerdP]

I think it would be good if JOSM would recognize this error

[skyper]

+1, I had the same thought.

[HeinerSchaefer]

+1, OK, with a speaking error message this should really help. Closed too fast, sorry.

[GerdP]

simple check for stack size

[GerdP]

The patch produces this popup for the bad example:

[GerdP]

The default presets never reach a stack size of more than 5 so I guess a threshold of 100 is a reasonable value. I assume it is possible to define more complex loops where a refers to b and b refers to c and c refers to a (similar to relations in OSM), so a perfect solution would show all elements that form the recursive dependency loop, but this would require much more code.

[simon04]

I like the simple solution from attachment:20578.patch​​

This is the first time an error w.r.t. recursive chunks has been reported since its introduction in r6558, so we probably don't super advanced error handing.

[GerdP]

In 17636/josm:

fix #20578: JOSM is out of memory - While adding a local xml preset

• add simple check for stack size