Crash after restart app

[Jean-BaptisteC]

How to Reproduce

• Close app
• Start app -> app crashed (never reproduce)

Versions affected
Android 13 - v53.0

[westnordost]

What do you mean with "close app"?

[Jean-BaptisteC]

Go to list of app opened and swipe StreetComplete to close it

[westnordost]

This puzzles me, how can a crash happen on cold start of the app?

Anyway, I noticed that this is a problem in tangram-es, so an upstream issue.

This seems to happen extremely scarcely so I won't bother with some kind of workaround that may or may not work.

[Helium314]

@westnordost do you remember the reason for

StreetComplete/app/src/main/java/de/westnordost/streetcomplete/screens/main/map/components/DownloadedAreaMapComponent.kt

Lines 16 to 19 in c456a05

	// tangram does not clear a layer properly on re-setting features on it, so let's remove
	// and re-add the whole layer
	layer?.remove()
	val layer = ctrl.addDataLayer(DOWNLOADED_AREA_LAYER)

I tried removing the part above and

-    private var layer: MapData? = null
+    private val layer: MapData = ctrl.addDataLayer(DOWNLOADED_AREA_LAYER)

and

+        layer.clear()
         layer.setFeatures(listOf(
             Polygon(
                 polygons.map { polygon -> polygon.map { it.toLngLat() } },
                 mapOf()
             )
         ))
-        this.layer = layer

and didn't have a crash so far (instead of once every ~10 app starts).

[westnordost]

What do you mean, reason for that? The reason is explained in the comment above.

Do you remember, we (still) have the issue that when you solve a quest and then zoom out, the solved quest seems to reappear (flickering, while zooming out) again, because apparently the pin is still in the cache for the other zooms or something. A similar phenomen only more noticeable (IIRC) could be seen with the downloaded area visualization.

[Helium314]

The reason is explained in the comment above.

"tangram does not clear a layer properly on re-setting features on it" isn't particularly clear on the issues it causes, that's why I asked. Thanks for the clarification.

So it's occasional crashes at startup or flickering in non-downloaded areas...
Since it only happens on startup, maybe starting with an empty layer instead of null helps. I'll try that for a while.