Crash with MAUI Android 7.0

[bertt]

A Mapsui MAUI (5.0.2 - net10.0-android) getting started app (https://mapsui.com/documentation/getting-started-maui.html) is crashing on Android 7.0 - API 24.0 (emulator and real device) while navigating map.

To reproduce:

• Install Android 7.0 - API 24.0 emulator

• Create getting started Mapsui MAUI app

• Run on emulator and navigate the map

Real device crash log see attached file.

crash_mapsui.txt

[bertt]

AI suggests something with JNI (local reference table overflow (max=512)), last 10 entries look like response headers.

12-31 10:40:59.494 F/art     (17306): art/runtime/indirect_reference_table.cc:116] JNI ERROR (app bug): local reference table overflow (max=512)
12-31 10:40:59.494 F/art     (17306): art/runtime/indirect_reference_table.cc:116] local reference table dump:
12-31 10:40:59.494 F/art     (17306): art/runtime/indirect_reference_table.cc:116]   Last 10 entries (of 512):
12-31 10:40:59.494 F/art     (17306): art/runtime/indirect_reference_table.cc:116]       511: 0x12f0bf70 java.lang.String "Age"
12-31 10:40:59.494 F/art     (17306): art/runtime/indirect_reference_table.cc:116]       510: 0x12ee6e80 java.lang.String "Age"
12-31 10:40:59.495 F/art     (17306): art/runtime/indirect_reference_table.cc:116]       509: 0x12ee6e20 java.lang.String "*"
12-31 10:40:59.495 F/art     (17306): art/runtime/indirect_reference_table.cc:116]       508: 0x12ef68f8 java.lang.String "Access-Control-A... (27 chars)
12-31 10:40:59.495 F/art     (17306): art/runtime/indirect_reference_table.cc:116]       507: 0x12cf6220 java.lang.String "bytes"
12-31 10:40:59.495 F/art     (17306): art/runtime/indirect_reference_table.cc:116]       506: 0x12e925e0 java.lang.String "Accept-Ranges"
12-31 10:40:59.495 F/art     (17306): art/runtime/indirect_reference_table.cc:116]       505: 0x12ef6e98 java.lang.String "S1767174059.2520... (26 chars)
12-31 10:40:59.495 F/art     (17306): art/runtime/indirect_reference_table.cc:116]       504: 0x12cee360 java.lang.String "X-Timer"
12-31 10:40:59.495 F/art     (17306): art/runtime/indirect_reference_table.cc:116]       503: 0x12ef6d78 java.lang.String "nidhogg.openstre... (25 chars)
12-31 10:40:59.495 F/art     (17306): art/runtime/indirect_reference_table.cc:116]       502: 0x12d67308 java.lang.String "X-TileRender"
12-31 10:40:59.495 F/art     (17306): art/runtime/indirect_reference_table.cc:116]   Summary:
12-31 10:40:59.495 F/art     (17306): art/runtime/indirect_reference_table.cc:116]       512 of java.lang.String (472 unique instances)
12-31 10:40:59.495 F/art     (17306): art/runtime/indirect_reference_table.cc:116] 
12-31 10:40:59.561 F/art     (17306): art/runtime/runtime.cc:403] Runtime aborting...

[pauldendulk]

Thanks for the report!

I did some chatgpting on the JNI problem, and it could be anything wrapping a java class but the most likely causes are HttpClient and HttpResponseMessage (and this is what we use in the TileLayer used in the the quick start app). We have only one HttpClient instance and we dispose the HttpResponseMessage so this seems to be correct.

This problem can occur in a correct implementation if the pressure is too high (which is more likely to be a problem on an old device). So perhaps there should be a way to reduce the pressure by doing less. One thing you can try is to change the number of parallel requests. This can be done with:

TileFetchPlanner.DefaultNumberOfSimultaneousFetches = 2; // Or you could try 1. The default is 4

This is a global static setting for all tile layers.

[bertt]

some more testing:

• setting TileFetchPlanner.DefaultNumberOfSimultaneousFetcher didn't have any effect

• when using targetframework 'net9.0-android' instead of 'net10.0-android' the crash does not occur

[pauldendulk]

Thanks. I won't dig into this anymore at this point, since it is an old device, and so far only reproduced on the emulator. At some Mapsui will compile to net10, so then we could test again. Also a newer sdk version may change things.

[janusw]

* when using targetframework 'net9.0-android' instead of 'net10.0-android' the crash does not occur

Seems to be a problem specific to .NET 10 then. Does the crash only occur on Android 7 (which is pretty old), or also on later versions?