/deleteblocks causes map blackouts

[0-afflatus]

using /deleteblocks to repair mapgen anomalies appears to be deleting the light completely in those areas. I'll provide a screenshot if necessary, but I think this is pretty self-explanatory.
This is a major bug IMO.

[paramat]

Screenshot might be useful, please include the border of the dark area too. Also which mapgen?

[0-afflatus]

mgv7

most of this appears to be caused by several invocations of /deleteblocks here 100
All three admins have spent time trying to /mapfix this yesterday and given up because it's just no fun at all.

I'll try to find some undamaged parts of the map and experiment with different invocations. However this damage is so extensive I think my only option is to unexplore large areas of the map.

[0-afflatus]

Ice ...
I think these are pure mapgen errors
The border may be from a /mapfix

[paramat]

Does it happen in mgv6?
Running any mods or subgames? best disable them all.

[Fixer-007]

I see moretrees here cough :} @paramat @VanessaE

[paramat]

Moretrees doesn't tend to cause shadows that big and over ocean. I'll check the deleteblocks code and see if it uses 'update lighting'. Please try without any mods enabled, and try in mgv6 too.

[0-afflatus]

This is proving to be really difficult to debug.

This is a mapgen bug - specific to grailtest in multiplayer mode. If you take a brief glance at https://github.com/0-afflatus/grailtest and particularly https://github.com/0-afflatus/grailtest/blob/master/mods/default/mapgen.lua you'll see how difficult it would be to strip it down.

@Fixer-007 if you look at the screenshots, it's pretty obviously not caused by moretrees. As this is happening in dry treeless biomes equally. The lightbugs triggered by moretrees only occur in small patches and are easily /mapfix-able.

This only happens in multiplayer AFAICS - singleplayer works as expected.
In multiplayer all new areas (using various recent -dev versions) are generating without light. It's not just a patch it is the whole mapblock. If I do a /deleblocks here on an old (lit) mapblock, lightbugs are introduced. This can be fixed using /mapfix, but it's happening over such wide areas that it's almost impossible to make any headway (we have 5 players on the case right now)

I'm really sorry, but setting up a multiplayer server running mgv6 or any other mapgen is more work that I can handle right now - there are only so many hours in the day. From the lack of other responses, I guess that this doesn't happen in minetest_game at all. This is the best I can come up with after a solid week of investigation. I will persevere with getting some information you can work on @paramat

[paramat]

Weird. Don't bother trying in mgv6 since that's complex.

[paramat]

I looked through grailtest and can't see any obvious error. All i can suggest is removing the 'biomelib' 'moretrees' 'plantlife' mods to see if they are the cause.

[0-afflatus]

I am working on this. So far I can report that mgv6 (in multiplayer mode) doesn't have this problem even with VanessaE's mods enabled. I will test without these mods, but I'm afraid this will take a few days more ...

[paramat]

Yes the overgeneration used in other mapgens seems to make lighting bugs worse.

[paramat]

@0-afflatus still occuring? We have had many lighting improvements recently.

[nerzhul]

can we have a confirmation on this issue ? else we may close the issue as it's 3 years old and we did some light fixes between

[0-afflatus]

I've been away for 3 years, just catching up ...
I stopped using 'biomelib' 'moretrees' and 'plantlife' mods and haven't encountered lighting bugs since.
I also gave up trying to run a server or develop anything, so the above is kind of meaningless.
I seem to be working on games again.

[paramat]

Thanks, i appreciate the update.