Error message for liquids with liquid_range of 0

[Elkien3]

Minetest version

Minetest 5.5.1 Windows 64 bit Release

OS / Hardware

Operating system: Windows 10
CPU: Intel i7-6700hq

Summary

I made a liquid node that has a liquid_range of 0, and I get error messages in chat when the liquid is supposed to be updated (when it's placed and when nodes near it are changed)
Example Error Message: Map::setNode(): Not allowing to place CONTENT_IGNORE while trying to replace "air" at (78,5,-34) (block (4,0,-3))
It has an error for each air node neighboring it and also itself.
Also I noticed if you add a liquid_alternative_flowing it will place that node around the liquid node, even though the liquid range is supposed to be 0.

Steps to reproduce

add a mod with this code:
minetest.register_node("water_bug:liquid", { description = "Liquid test", tiles = {"default_stone.png"}, paramtype = "light", liquidtype = "source", liquid_range = 0, })
place this node somewhere and you should get the error message.

[Wuzzy2]

Just add liquid_alternative_flowing = "water_bug:liquid", liquid_alternative_source = "water_bug:liquid"` to the definition and it should work.

[Elkien3]

That does stop the error message, thanks for the tip!

[appgurueu]

Not a bug, just a poor & spammy error message that should be raised at load time when the invalid liquid def is made.

[sfan5]

Sounds like a definite bug to me, if liquid range is zero then the liquid should never try to flow anywhere and hence not need any flowing/source node defined.
Very low priority though, it's already possible to get liquid appearance without its physics (drawtype = "liquid", liquidtype = "none").

[Elkien3]

My reason for a node like this is to get the liquid_pointable effect

[sfence]

@sfan5 liquid_alternative_flowing and liquid_alternative_source fields is used to detect some liquid in content_mapblock.cpp.
So is a better way to fix this to add some check to the register_item function, to cause an error if some of these fields are missing, or to change the way, how method sameLiquidRender works?

[appgurueu]

My reason for a node like this is to get the liquid_pointable effect

There now is a "pointability" API (introduced in #13992). If you have control over the tool, that should be sufficient.