Was able to retreat to a just captured territory

[VictoryFirst]

I was playing a game of Europe and on the first turn during the combat phases something weird happened. My units that fought in Ukraine were able to retreat to East Poland, even though no land units moved through East Poland to reach Ukraine and East Poland was captured in a battle in that same turn.

Here is the save file: Bug.tsvg

[Panther]

@VictoryFirst Where can I download the map? It isn’t offered by TripleA itself…

Never mind, found it in the map repos.

[Panther]

@VictoryFirst said in Was able to retreat to a just captured territory:

I was playing a game of Europe and on the first turn during the combat phases something weird happened. My units that fought in Ukraine were able to retreat to East Poland, even though no land units moved through East Poland to reach Ukraine and East Poland was captured in a battle in that same turn.

Unless specific rules apply to this specific map, this appears to be a bug. When retreating has Eastern Poland been explicitly indicated as a territory to retreat to?

However, I recreated a similar situation in Global1940 map - and there it works as expected.
So I suppose it is a map-related bug rather than an engine related one.

[VictoryFirst]

@Panther said in Was able to retreat to a just captured territory:

When retreating has Eastern Poland been explicitly indicated as a territory to retreat to?

Yes, Eastern Poland was showed in the list along with Ukraine (which was actually the only legal territory to retreat to).

So I suppose it is a map-related bug rather than an engine related one.

That could be the cause of the problem, but I am not sure how that is possible. The rules for retreat are not governed by the map itself but by the engine, with a couple of properties as exceptions like “Retreating Units Remain In Place”.
Is it possible that any of the properties that are set for this map caused this bug?

[Panther]

@VictoryFirst said in Was able to retreat to a just captured territory:

Is it possible that any of the properties that are set for this map caused this bug?

I have no clue found the culprit that caused the misbehaviour in your game.

I have recreated the scenario starting with a new game and did a couple of tests without the attacking bomber. In no case preaviously token East Poland had been offered as territory to retreat to. In every case only legal territories had been offered.

But: When I added the bomber’s attack, the bomber flies over (pre-battle) East Poland. By this action it seems to open and later offer a retreat route to East Poland. What of course usually is against the rules.

[VictoryFirst]

@Panther said in Was able to retreat to a just captured territory:

But: When I added the bomber’s attack, the bomber flies over (pre-battle) East Poland. By this action it seems to open and later offer a retreat route to East Poland. What of course usually is against the rules.

Yes, I was thinking of that too. Does that also happen in other games like G40?

[Panther]

@VictoryFirst said in Was able to retreat to a just captured territory:

Yes, I was thinking of that too. Does that also happen in other games like G40?

It never obivously occurred - as this has never been reported. But that is something to test now.

[Panther]

@VictoryFirst
Tested with G40:

_2024-12-2-World-War-II-Global-1940-2nd-Edition.tsvg

So it does not happen in Global1940.

But I don’t know which core ruleset (old) Europe is based on codewise. So it might be that there are older core games where this issue has been incorrectly implemented.

I will start doing some tests recursively now. Maybe you can do some tests with older games, too.

[VictoryFirst]

Very strange. At the moment I am comparing the property lists of G40 and Europe, trying to see if there is any noteable difference there that might cause the issue.

[Panther]

@VictoryFirst

v3-v5 don’t show the issue, they work correctly. Now testing v2.

[VictoryFirst]

I tested with Classic and was able to reproduce the issue

Bug also occurs in classic.tsvg

So here the fighter from Mocsow attacked Eastern Europe through Ukraine which was captured in a battle that same turn, and the land units are able to retreat from Eastern Europe to Ukraine.

[Panther]

@VictoryFirst

And I tested v2 and the issue does not occur there.
So old Europe map is codewise based on v1 ruleset.
I am now going to check the retreat rules of v1.

[VictoryFirst]

Just checked Revised, no problems there.

[Panther]

@VictoryFirst Revised=v2

[Panther]

@VictoryFirst

OK, so the old Europe Map codewise is based on Classic (v1) rules. Here the retreat rule is as follows:

So the plane came from a territory that - at the time of retreating - is friendly (as it was captured before). The rules are different from other editions.

So engine-wise the behaviour is correct. The Europe map is codewise based on a ruleset that allows this special retrat move. It’s against the Europe rulebook however.

[VictoryFirst]

@Panther

Ah, that explains it. Thanks!

[Panther]

@VictoryFirst

It looks like the players - once again - have to take care of the game rules themselves. As v1 rules differ from the Europe 1999 -rulebook.