Make it possible to forcibly research a tech that is instantly researchable after TC due to tech leak

[daavko]

Is your feature request related to a problem? Please describe.
Currently, if RNGeezus wants, a player may end up in a situation where they have more bulbs stored than their current research target costs, due to tech leak. This happens due to player processing order, where a player might gain just-not-enough bulbs to research a tech, but a player processed later might have enough, causing the cost to drop due to tech leak. Sometimes you can then "force" the game to research the tech by switching to another one that's sufficiently expensive (so you don't insta-research it and lose your bulbs) and then switching back, forcing the server to process the research. This may not always be possible, forcing the player to wait until next TC.

Describe the solution you'd like
Two potential solutions:

1. Make the server somehow find out if tech leak would affect players that have already been processed, and process their research again (this might do weird stuff with obsoletions and stuff, I don't know the exact sequence of events in the TC sequence)
2. Quite a bit simpler, when the player sets their tech goal to the one they're currently researching, the server accepts this and processes it as if the player switched to any other tech. I'm pretty sure this would mean just removing lines 1020-1022 in techtools.cpp, but this is only from a cursory search. It does appear that the client sends the "switch research" packet even when the player clicks on a tech they're currently researching.

Describe alternatives you've considered
Leaving it as-is...

Additional context
No additional context

[lmoureaux]

Looks like techs are updated first, so obsoletions and so on shouldn't be affected.

[lmoureaux]

I can see two options to take tech leak into account during TC:

• Do multiple rounds of the current "lucky last" algorithm. This is easy to implement.
• All players that can research their tech pay the full price, then we check again with the reduced prices. So always boost behind players more.

Both cases enable a lot of gambling and micromanagement, especially in team games with a lot of info available.

Should getting techs through diplomacy also update other players' research?

[jwrober]

Need to figure out a way to easily reproduce this event as it typically only happens on LT multiplayer games.

[jwrober]

Should getting techs through diplomacy also update other players' research?

My thinking here is that any time a tech is "researched" even if its given in a diplomacy treaty is the same as if the player researched the old fashioned way.

[jwrober]

Re-opening this issue. The PR doesn't do what is expected.

[lmoureaux]

The following check in the server code prevents the player_research packet from refreshing the current tech:

freeciv21/server/techtools.cpp

Lines 998 to 1000 in 470a541

	if (research->researching == tech) {
	return;
	}

[jwrober]

Any I'll effects if we remove it?

[lmoureaux]

None that I could find by reading the code, but I haven't tried