I got a lua error in a multiplayer game from Factorio 2.0.67, canal excavator 1.13.3. I was placing canal excavation tiles and excavators from a blueprint using construction bots. This may have something to do with placing an excavation tile on an already mined or partly mined but non-water tile. Here's the last part of the logs. Full logfile at https://drive.google.com/file/d/15ZDRYUBzUDLFghrvGnN6zEXdUC8IR_ta/view?usp=sharing – too long for this message.

128307.454 Info AppManagerStates.cpp:2111: Saving finished
128663.588 Error MainLoop.cpp:1468: Exception at tick 10929369: The mod Canal Excavator (1.13.3) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event canal-excavator::on_built_entity (ID 6)
__canal-excavator__/control/events/entityBuilt.lua:58: attempt to index local 'undo_item' (a nil value)
stack traceback:
    __canal-excavator__/control/events/entityBuilt.lua:58: in function 'undo_last_create_digable_ghost'
    __canal-excavator__/control/events/entityBuilt.lua:109: in function 'handle_ghost_digable_tile'
    __canal-excavator__/control/events/entityBuilt.lua:125: in function <__canal-excavator__/control/events/entityBuilt.lua:115>
128663.588 Error ServerMultiplayerManager.cpp:84: MultiplayerManager failed: "The mod Canal Excavator (1.13.3) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event canal-excavator::on_built_entity (ID 6)
__canal-excavator__/control/events/entityBuilt.lua:58: attempt to index local 'undo_item' (a nil value)
stack traceback:
    __canal-excavator__/control/events/entityBuilt.lua:58: in function 'undo_last_create_digable_ghost'
    __canal-excavator__/control/events/entityBuilt.lua:109: in function 'handle_ghost_digable_tile'
    __canal-excavator__/control/events/entityBuilt.lua:125: in function <__canal-excavator__/control/events/entityBuilt.lua:115>"
128663.588 Info ServerMultiplayerManager.cpp:808: updateTick(10929369) changing state from(InGame) to(Failed)
128663.604 Quitting: multiplayer error.
128663.605 Info GlobalContext.cpp:781: Deleting active scenario.
128664.136 Info ServerMultiplayerManager.cpp:146: Quitting multiplayer connection.
128664.136 Info ServerMultiplayerManager.cpp:808: updateTick(18446744073709551615) changing state from(Failed) to(Closed)
128664.136 Info ServerMultiplayerManager.cpp:166: Deleting active scenario (global = true).
128664.137 Info HttpSharedState.cpp:57: Downloading https://multiplayer.factorio.com/remove-game/511928
128664.618 Info UDPSocket.cpp:238: Closing socket
128664.618 Info UDPSocket.cpp:268: Socket closed
128664.621 Goodbye

Hi, thanks for letting me know! I'll see what I can do. Could you maybe share your mod-list so I can better reproduce the error?

The mod list is near the start of the log file.

   0.128 Loading mod core 0.0.0 (data.lua)
   0.149 Loading mod base 2.0.76 (data.lua)
   0.352 Loading mod aai-containers 0.3.2 (data.lua)
   0.368 Loading mod Adjustable-Inventory-Size 2.2.0 (data.lua)
   0.375 Loading mod Advanced-Electric-Revamped-v16 0.7.7 (data.lua)
   0.385 Loading mod blueprint-shotgun 0.2.19 (data.lua)
   0.394 Loading mod classic-rocket-silo 0.1.2 (data.lua)
   0.403 Loading mod FactorySearch 1.14.0 (data.lua)
   0.410 Loading mod FilterChests 1.2.0 (data.lua)
   0.417 Loading mod flib 0.16.5 (data.lua)
   0.426 Loading mod hide-uis 1.0.1 (data.lua)
   0.433 Loading mod IntermodalContainers 2.1.2 (data.lua)
   0.443 Loading mod inventory-mover 0.1.6 (data.lua)
   0.450 Loading mod inventory-sensor-improved 2.0.1 (data.lua)
   0.467 Loading mod miniloader-redux 0.13.0 (data.lua)
   0.484 Loading mod qol_research 3.4.2 (data.lua)
   0.495 Loading mod radar-equipment 0.1.6 (data.lua)
   0.504 Loading mod RealisticDecorationCleanup 2.0.2 (data.lua)
   0.512 Loading mod underground-pipe-pack 2.0.6 (data.lua)
   0.570 Loading mod canal-excavator 1.13.3 (data.lua)
   0.586 Loading mod base 2.0.76 (data-updates.lua)
   0.596 Loading mod CircuitNetworkItemsStackTo50 0.1.0 (data-updates.lua)
   0.605 Loading mod classic-rocket-silo 0.1.2 (data-updates.lua)
   0.614 Loading mod FactorySearch 1.14.0 (data-updates.lua)
   0.623 Loading mod FilterChests 1.2.0 (data-updates.lua)
   0.631 Loading mod IntermodalContainers 2.1.2 (data-updates.lua)
   0.643 Loading mod inventory-sensor-improved 2.0.1 (data-updates.lua)
   0.661 Loading mod miniloader-redux 0.13.0 (data-updates.lua)
   0.697 Loading mod aai-containers 0.3.2 (data-final-fixes.lua)
   0.706 Loading mod Adjustable-Inventory-Size 2.2.0 (data-final-fixes.lua)
   0.715 Loading mod Advanced-Electric-Revamped-v16 0.7.7 (data-final-fixes.lua)
   0.724 Loading mod FilterChests 1.2.0 (data-final-fixes.lua)
   0.732 Loading mod IntermodalContainers 2.1.2 (data-final-fixes.lua)
   0.758 Loading mod inventory-sensor-improved 2.0.1 (data-final-fixes.lua)
   0.778 Loading mod miniloader-redux 0.13.0 (data-final-fixes.lua)
   0.835 Loading mod sbUnlimitedDeconstruction 1.0.1 (data-final-fixes.lua)
   0.848 Loading mod canal-excavator 1.13.3 (data-final-fixes.lua)

Mods:
- https://mods.factorio.com/mod/aai-containers large chests.
- https://mods.factorio.com/mod/miniloader-redux loaders useful with large chests to input/output balance, input/output lane balance, input/output prioritize, or filter.
- https://mods.factorio.com/mod/underground-pipe-pack Advanced Fluid Handling: long underground pipe connectors, valves, and more. The valves and pumps got upgrades for Factorio 2.0.
- https://mods.factorio.com/mod/Advanced-Electric-Revamped-v16 solar panels and accumulators compressed to smaller area.
- https://mods.factorio.com/mod/blueprint-shotgun Blueprint shotgun: personal construction the fun way.
- https://mods.factorio.com/mod/canal-excavator dig for water, but only by extending existing water (you can landfill over).
- https://mods.factorio.com/mod/CircuitNetworkItemsStackTo50 restore stack size of power switches and speakers to 50.
- https://mods.factorio.com/mod/classic-rocket-silo space science arrives into the rocket silo, not a landing pad.
- https://mods.factorio.com/mod/FactorySearch other player built a mall but how do I find items in it.
- https://mods.factorio.com/mod/FilterChests chest inventory slots can be filtered.
- https://mods.factorio.com/mod/First_One_Is_Free carry one of each type of item for free, not counting in your inventory size.
- https://mods.factorio.com/mod/qol_research research bonuses for personal inventory size, mining speed, movement speed, reach.
- https://mods.factorio.com/mod/Adjustable-Inventory-Size start with 20 fewer inventory slots to counteract the unbalanced inventory bonus from the two previous mods.
- https://mods.factorio.com/mod/hide-uis show or hide minimap or other parts of HUD easily with keyboard shortcuts or a graphical menu.
- https://mods.factorio.com/mod/inventory-sensor-improved read number of empty slots in a chest, or rocket parts in a rocket, and more.
- https://mods.factorio.com/mod/IntermodalContainers compress ores or other intermediates on belts, but you have to deal with returning the empty boxes.
- https://mods.factorio.com/mod/inventory-mover move all items from one chest to another without having to stash your personal inventory.
- https://mods.factorio.com/mod/radar-equipment put in a tank.
- https://mods.factorio.com/mod/RealisticDecorationCleanup remove annoying decoratives like grass, small rocks, tree stumps, whenever you build or pave.
- https://mods.factorio.com/mod/sbUnlimitedDeconstruction decon planners have more slots. this will be redundant in Factorio 2.1.
Mod settings:
- AAI Containers & Warehouses:
- Reduce 1×1 container collision: false
- Adjustable inventory size:
- Enable: true
- Player inventory size: 60
- Advanced Solar High Resolution:
- Enabled tiers: Advanced + Elite
- Intermodal containers:
- Containerization machine dimensions: 3×4
- Stacks per container: 0.4
- Loaded container stack size: 10
- Miniloaders (Redux):
- Chute: true
- Quality of Life research:
- Crafting speed research: false
- Custom configuration: 1,23,crafting-speed,150*L,automation-science-pack,inventory-size,75,chemical-science-pack,150+300*l,logistic-science-pack,utility-science-pack,150+150*(l-1)*l,space-science-pack,150*2^L,mining-speed,75*l,150*l*(l+1),movement-speed,175*L,225*L,300*L,500*2^L,player-reach,production-science-pack,250*2^L,5,1,1,5,59,0,0,2,10,1,1,3,4,4,1,5,0,0,5,10,1,1,3,1,5,1,1,6,7,20,3,1,3,1,8,1,6,4,5,1,1,9,10,25,4,1,3,1,8,1,6,1,9,0,5,1,1,11,12,60,5,1,3,1,8,1,6,1,9,1,11,13,2,1,25,0,0,14,10,1,1,3,3,25,1,1,8,15,10,2,1,3,1,8,16,5,4,5,0,0,2,10,1,1,3,4,5,2,1,8,17,15,2,1,3,1,8,4,5,2,1,6,18,20,3,1,3,1,8,1,6,4,5,2,1,9,19,25,4,1,3,1,8,1,6,1,9,0,5,4,1,11,20,30,5,1,3,1,8,1,6,1,9,1,11,21,5,3,1,0,0,2,10,1,1,3,3,1,2,1,8,17,15,2,1,3,1,8,3,1,2,1,6,18,20,3,1,3,1,8,1,6,3,1,2,1,22,19,25,4,1,3,1,8,1,6,1,22,0,1,3,1,11,23,30,5,1,3,1,8,1,6,1,22,1,11
Map settings: water coverage 75%, no enemy bases, no pollution.

For about 9 more days, this is also an ongoing game on a public server that you can connect to at 74.80.183.162:10010 ; or download saves from https://m45sci.xyz/u/fact2/autosaves/k/ . After the game finishes, final save will show up in https://m45sci.xyz/u/fact2/archive/2.0%20maps/ with a name similar to k-peaceful-QoL-twoweek-2026-05-30.zip (I'm not sure about the exact name). The canal excavator mod was added later than the start of the map.

Probably fixed in version 1.13.4.

Good to hear, thanks again for the help of tracking the issue down!