Merging/Unmerging chests now results in a crash, regardless of the type of chest being merged/unmerged:

Error while running event WideChests::on_player_alt_selected_area (ID 53)
WideChests/control_init.lua:30: Arguments count error for 'get_inventory_size': Expected 1 argument but 2 were given
stack traceback:
[C]: in function 'get_inventory_size'
WideChests/control_init.lua:30: in function 'can_move_inventories'
WideChests/scripts/event_handlers/split_chest.lua:56: in function <WideChests/scripts/event_handlers/split_chest.lua:47>

Turns out there was an update that I didn't receive because I've been playing for more than 20 hours.
Oops.

Problem has disappeared now, sorry for the bother. Thank you for this amazing mod!

I'm having the same issue. Mod is 6.1.0, Factorio Space Age 2.0.15

Error while running event WideChests::on_player_selected_area (ID 52)
WideChests/control_init.lua:30: Arguments count error for 'get_inventory_size': Expected 1 argument but 2 were given
stack traceback:
[C]: in function 'get_inventory_size'
WideChests/control_init.lua:30: in function 'can_move_inventories'
WideChests/scripts/event_handlers/merge_chest.lua:195: in function <WideChests/scripts/event_handlers/merge_chest.lua:187>

Same here, I am getting this issue as well. Tried to merge a couple steel crates and errored out.

The mod Merging Chests (6.1.0) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event WideChests::on_player_selected_area (ID 52)
WideChests/control_init.lua:30: Arguments count error for 'get_inventory_size': Expected 1 argument but 2 were given
stack traceback:
[C]: in function 'get_inventory_size'
WideChests/control_init.lua:30: in function 'can_move_inventories'
WideChests/scripts/event_handlers/merge_chest.lua:195: in function <WideChests/scripts/event_handlers/merge_chest.lua:187>

I believe the mod is using a new feature from the 2.0.18 beta: https://lua-api.factorio.com/2.0.18/classes/LuaEntityPrototype.html#get_inventory_size

Should be fixed in 2.0.20, but that hasn't rolled to everyone apparently

Mod doesn't specify dependency to "base>=2.0.18". I'll remove broken version from mod portal and provide 6.1.1 with correct dependencies.