Crash when using a deconstruction planner aboveground on many objects including beltlayer entrances

The mod Beltlayer (0.5.2) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event beltlayer::on_player_deconstructed_area (ID 69)
The mod Beltlayer (0.5.2) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event beltlayer::on_marked_for_deconstruction (ID 20)
beltlayer/lualib/BaseEditor/BaseEditor.lua:853: attempt to index local 'bpproxy_entity' (a nil value)
stack traceback:
beltlayer/lualib/BaseEditor/BaseEditor.lua:853: in function 'create_deconstruction_proxy'
beltlayer/lualib/BaseEditor/BaseEditor.lua:1118: in function 'on_marked_for_deconstruction'
beltlayer/Editor.lua:367: in function 'on_marked_for_deconstruction'
beltlayer/control.lua:34: in function <beltlayer/control.lua:34>
[C]: in function 'order_deconstruction'
beltlayer/lualib/BaseEditor/BaseEditor.lua:921: in function 'order_underground_deconstruction'
beltlayer/Editor.lua:322: in function <beltlayer/Editor.lua:314>
(...tail calls...)
beltlayer/Editor.lua:358: in function 'on_player_deconstructed_area'
beltlayer/control.lua:36: in function <beltlayer/control.lua:36>
stack traceback:
beltlayer/lualib/BaseEditor/BaseEditor.lua:921: in function 'order_underground_deconstruction'
beltlayer/Editor.lua:322: in function <beltlayer/Editor.lua:314>
(...tail calls...)
beltlayer/Editor.lua:358: in function 'on_player_deconstructed_area'
beltlayer/control.lua:36: in function <beltlayer/control.lua:36>
stack traceback:
[C]: in function 'order_deconstruction'
beltlayer/lualib/BaseEditor/BaseEditor.lua:921: in function 'order_underground_deconstruction'
beltlayer/Editor.lua:322: in function <beltlayer/Editor.lua:314>
(...tail calls...)
beltlayer/Editor.lua:358: in function 'on_player_deconstructed_area'
beltlayer/control.lua:36: in function <beltlayer/control.lua:36>

Using the same mods as last time, most notably Space Exploration.

Could you upload the save so I can have a look? Or is it the same one from your other thread? I haven't had a chance to look at that yet.

Same one from my other thread, just a different point in time. No rush, it's playable but occasionally buggy. Wish I knew enough lua to understand what was going on.

I figured out the cause. When you mark something for deconstruction underground, Beltlayer creates a “proxy” on the surface so bots can mine it. The proxy is also a transport belt, and it’s not possible to have two transport belts in the same tile.

So anytime you mark a belt for deconstruction underground and there’s another belt on the surface directly above, you get this crash. The fix is possible but complicated.

EDIT: double post

Cool! Nice to know why it only happens intermittently

This should be fixed with v0.6.0. Please give it a try.