Fix aircraft disappearing when their carrier is teleported (#7035)

* Fix carrier teleporting without moving airplanes

* Unit test to ensure aircraft and carriers are teleported togother

* Fix other cases where teleportation may occur

* Simplify unit test condition

* Update linting and move return condition

* Allow override for teleporting transported units

* Make sure test catches if transported units get deleted

* Reviews

core/src/com/unciv/logic/map/UnitMovementAlgorithms.kt

@@ -370,10 +370,12 @@ class UnitMovementAlgorithms(val unit: MapUnit) {
      * Displace a unit - choose a viable tile close by if possible and 'teleport' the unit there.
      * This will not use movement points or check for a possible route.
      * It is used e.g. if an enemy city expands its borders, or trades or diplomacy change a unit's
-     * allowed position.
+     * allowed position. Does not teleport transported units on their own, these are teleported when
+     * the transporting unit is moved.
      * CAN DESTROY THE UNIT.
      */
     fun teleportToClosestMoveableTile() {
+        if (unit.isTransported) return // handled when carrying unit is teleported
         var allowedTile: TileInfo? = null
         var distance = 0
         // When we didn't limit the allowed distance the game would sometimes spend a whole minute looking for a suitable tile.
@@ -394,6 +396,7 @@ class UnitMovementAlgorithms(val unit: MapUnit) {
                 if (allowedTile != null) break
             }
         }
+        val origin = unit.getTile()
         if (allowedTile != null) {
             unit.removeFromTile() // we "teleport" them away
             unit.putInTile(allowedTile)
@@ -401,6 +404,15 @@ class UnitMovementAlgorithms(val unit: MapUnit) {
             if (unit.isSleeping() || unit.isFortified())
                 unit.action = null
             unit.mostRecentMoveType = UnitMovementMemoryType.UnitTeleported
+
+            // bring along the payloads
+            val payloadUnits = origin.getUnits().filter { it.isTransported && unit.canTransport(it) }.toList()
+            for (payload in payloadUnits) {
+                payload.removeFromTile()
+                payload.putInTile(allowedTile)
+                payload.isTransported = true // restore the flag to not leave the payload in the city
+                payload.mostRecentMoveType = UnitMovementMemoryType.UnitTeleported
+            }
         }
         // it's possible that there is no close tile, and all the guy's cities are full.
         // Nothing we can do.

tests/src/com/unciv/logic/map/UnitMovementAlgorithmsTests.kt

@@ -100,7 +100,7 @@ class UnitMovementAlgorithmsTests {
             if (terrain.impassable) continue
             tile.baseTerrain = terrain.name
             tile.setTransients()
-            
+
             for (type in ruleSet.unitTypes) {
                 unit.baseUnit = BaseUnit().apply { unitType = type.key; ruleset = ruleSet }
                 Assert.assertTrue("%s cannot be at %s".format(type.key, terrain.name),
@@ -197,7 +197,7 @@ class UnitMovementAlgorithmsTests {
             civInfo.tech.techsResearched.remove("Astronomy")
 
             Assert.assertTrue("$type cannot be in Ocean until Astronomy",
-                    (unit.baseUnit.isMelee() || unit.baseUnit.isRanged()) 
+                    (unit.baseUnit.isMelee() || unit.baseUnit.isRanged())
                                 != unit.movement.canPassThrough(tile))
 
             civInfo.tech.techsResearched.add("Astronomy")
@@ -208,7 +208,7 @@ class UnitMovementAlgorithmsTests {
     fun canNOTPassThroughTileWithEnemyUnits() {
         tile.baseTerrain = Constants.grassland
         tile.setTransients()
-        
+
         unit.currentTile = tile
 
         val otherCiv = CivilizationInfo()
@@ -451,4 +451,41 @@ class UnitMovementAlgorithmsTests {
             unit.currentTile == newTiles.last() && otherUnit.civInfo == unit.civInfo)
     }
 
-}
+    @Test
+    fun `can teleport transport and its transported units to the same tile`() {
+        civInfo.nation.name = Constants.spectator
+
+        tile.baseTerrain = Constants.ocean
+        tile.position.set(0f, 0f)
+        tile.setTransients()
+        createOpponentCivAndCity()
+        val newTiles = generateTileCopies(3)
+
+        setupMilitaryUnitInTheCurrentTile("Aircraft Carrier")
+        unit.owner = civInfo.civName
+        unit.civInfo = civInfo
+        unit.baseUnit.uniques.add("Can carry [2] [Aircraft] units")
+        unit.updateUniques(ruleSet)
+        civInfo.addUnit(unit, false)
+
+        val fighters = ArrayList<MapUnit>()
+        for (i in 0..1) {
+            val newFighter = MapUnit()
+            newFighter.baseUnit = BaseUnit().apply { unitType = "Fighter"; ruleset = ruleSet }
+            newFighter.owner = civInfo.civName
+            newFighter.civInfo = civInfo
+            newFighter.currentTile = unit.getTile()
+            tile.airUnits += newFighter
+            newFighter.name = "Fighter"
+            newFighter.isTransported = true
+            civInfo.addUnit(newFighter, false)
+            fighters += newFighter
+        }
+
+        // simulate ejecting all units within foreign territory
+        for (unit in civInfo.getCivUnits()) unit.movement.teleportToClosestMoveableTile()
+        Assert.assertTrue("Transport and transported units must be teleported to the same tile",
+            civInfo.getCivUnits().toList().size == 3 && civInfo.getCivUnits().all { it.getTile() == newTiles.last() })
+    }
+
+}