[2.1.16] Roboport entities do not refresh roboport connections following mod update

[MeteorSwarm]

Whether this issue should be considered a bug or a modding interface request is unclear to me, so I will post it as a bug.

This is in response to this bug report I've received.

Recently, I posted an update to Muluna that increased the logistic range of burner roboports from the range of vanilla roboports to a value twice as high. This user reports that burner roboports placed before this change to range do not automatically update their logistic networks to connect to the new logistic network they are in range of. Deleting the burner roboport and placing another one in the same position results in the new roboport being properly connected as expected.

It makes sense to me that logistic networks would only be updated on building new roboports, but there seems to be no way to account for changes to roboport ranges following mod updates, leaving stale roboports that are unintuitively disconnected from other parts of the logistic network. If there was a function to make roboports reevaluate their logistic network, I would call that function in a migration, but that function doesn't exist. I could make a script delete and reconstruct every burner roboport, but that could cause unintended consequences.

This problem could be fixed in the following ways:
1. When checking the consistency of saves, if any roboport prototypes have had their logistic range updated, their logistic networks should be reevaluated, as if they were built for the first time.
2. Add a function to LuaEntity that reevaluates a roboport's logistic network. This function could be invoked by me in a migration to fix this user's save.

[Rseding91]

It looks like roboports need to implement update_connections https://lua-api.factorio.com/stable/cla ... onnections

[Rseding91]

I've made update_connections handle this for the next release.

[MeteorSwarm]

Thank you! I've tested this migration in 2.1.17, and I can confirm it addresses this issue. I was initially confused when I did not notice any update to the description of LuaEntity.update_connections() in the latest documentation, so you should definitely update that documentation to mention that roboport connections are also updated.