gui/pathable crashes with multiple depots when one is underwater

[vityav]

I've found (don't ask how) that if you have multiple trade depots, and one has been submerged underwater, that running gui/pathable and clicking on the depot tab will lock up the game. After finding this I tested a number of situations to try to narrow it down and it seems that there have to be multiple depots and one must be underwater (not merely inaccessible). Any other conditions seem to work fine. I tested with the underwater depot both in a completely sealed room, and behind a grate that led out to the ocean, and both conditions behaved the same. Using liquids to drain the water in any crashing situation led to it working. Adding the water back and running again would return to crashing.

A Exists	A Accessible	A Submerged	B Exists	B Accessible	B Submerged	✔️Works/Crashes❌
✔️	✔️	❌				✔️
✔️	❌	✔️				✔️
✔️	✔️	❌	✔️	✔️	❌	✔️
✔️	❌	❌	✔️	✔️	❌	✔️
✔️	❌	✔️	✔️	✔️	❌	❌

Version: Windows 50.13-r4

[vityav]

Adding a save for debugging.
region6.zip

[lethosor]

Speculation: I think there is a special "not walkable" tile group, which is probably getting assigned here if the depot itself is truly submerged (i.e. not just in an enclosed room that happens to be submerged and unreachable). We may not be handling depots with that group assigned correctly. I can't easily explain why that would only happen if two depots are present from a quick look at pathable.cpp, though.

[vityav]

If I edit line 316 in pathable.cpp; if (!cache_scan_for_painting) to if (cache_scan_for_painting) (or just edit out the if statement entirely) , it works. It paths to the non-submerged depot, indicates all submerged tiles as impassible, and everything seems to behave the way I'd expect without it (including zooming between available depots if I make them both accessible).

I can also just edit out the call to wagon_flood and get incorrect results but no crash. I don't know why wagon_flood works if my only depot is submerged but fails when it's one of multiple depots, though. I feel like somewhere something is getting set to indicate that a depot should be accessible, and then the loop checks for routes to all depots expecting them all to be accessible? I'm still digging but calling it a night for now.

Functioning example: