[kovarex][0.17.8] Crash when removing combinator

[AnatolySwE]

Every time I try to remove this combinator the game crashes.
There is no difference when I try to do that by hand or using robots.
A similar problem once occured when I was trying to remove a power pole (but have no logs from that incident).

[Twinsen]

That combinator is in an invalid state. It has a green connection to a non-existent entity.
Do you remember how it was built, connected and disconnected? And what it was connected to?

[kovarex]

Hello, this error is most probably related to the addition of circuit network into the undo logic I did for 0.17.8

What I did for 0.17.9:

• I fixed 2 things that were related to that problem and probably caused this invalid state.
• Added more checks to make sure that this kind of error is noticed as soon as possible.
• Added migration for saves before 0.17.9 that removes the invalid connections

This means, that the problem will probably not happen again, but if it does we should know it sooner.

[AnatolySwE]

I've tried to recreate this crash in previous save. So.. this is what I've got

In action

This save has full version of my combinator build