removeImprovement convenience function

core/src/com/unciv/logic/GameStarter.kt

@@ -404,7 +404,7 @@ object GameStarter {
             if (tile.improvement != null
                 && tile.getTileImprovement()!!.isAncientRuinsEquivalent()
             ) {
-                tile.changeImprovement(null) // Remove ancient ruins in immediate vicinity
+                tile.removeImprovement() // Remove ancient ruins in immediate vicinity
             }
         }
     }

core/src/com/unciv/logic/battle/Battle.kt

@@ -892,7 +892,7 @@ object Battle {
         fun applyPillageAndFallout() {
             if (tile.getUnpillagedImprovement() != null && !tile.getTileImprovement()!!.hasUnique(UniqueType.Irremovable)) {
                 if (tile.getTileImprovement()!!.hasUnique(UniqueType.Unpillagable)) {
-                    tile.changeImprovement(null)
+                    tile.removeImprovement()
                 } else {
                     tile.setPillaged()
                 }
@@ -1202,7 +1202,7 @@ object Battle {
             && attacker.hasUnique(UniqueType.DestroysImprovementUponAttack, conditionalState)
         ) {
             val currentTileImprovement = attackedTile.improvement
-            attackedTile.changeImprovement(null)
+            attackedTile.removeImprovement()
             defender.getCivInfo().addNotification(
                 "An enemy [${attacker.unit.baseUnit.name}] has destroyed our tile improvement [${currentTileImprovement}]",
                 LocationAction(attackedTile.position, attacker.getTile().position),

core/src/com/unciv/logic/city/managers/CityFounder.kt

@@ -53,7 +53,7 @@ class CityFounder {
         })
             tile.removeTerrainFeature(terrainFeature)
 
-        tile.changeImprovement(null)
+        tile.removeImprovement()
         tile.improvementInProgress = null
 
         val ruleset = civInfo.gameInfo.ruleset

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

@@ -615,7 +615,7 @@ class TileMap(initialCapacity: Int = 10) : IsPartOfGameInfoSerialization {
             .map { it to StartingLocation(it.position, it.improvement!!.removePrefix(startingLocationPrefix)) }
             .sortedBy { it.second.nation }  // vanity, or to make diffs between un-gzipped map files easier
             .forEach { (tile, startingLocation) ->
-                tile.changeImprovement(null)
+                tile.removeImprovement()
                 startingLocations.add(startingLocation)
             }
         setStartingLocationsTransients()

core/src/com/unciv/logic/map/mapgenerator/NaturalWonderGenerator.kt

@@ -1,14 +1,14 @@
 package com.unciv.logic.map.mapgenerator
 
 import com.unciv.Constants
-import com.unciv.utils.debug
-import com.unciv.logic.map.tile.Tile
 import com.unciv.logic.map.TileMap
+import com.unciv.logic.map.tile.Tile
 import com.unciv.models.ruleset.Ruleset
 import com.unciv.models.ruleset.tile.Terrain
 import com.unciv.models.ruleset.tile.TerrainType
 import com.unciv.models.ruleset.unique.Unique
 import com.unciv.models.ruleset.unique.UniqueType
+import com.unciv.utils.debug
 import kotlin.math.abs
 import kotlin.math.roundToInt
 
@@ -204,7 +204,7 @@ class NaturalWonderGenerator(val ruleset: Ruleset, val randomness: MapGeneration
     private fun clearTile(tile: Tile){
         tile.setTerrainFeatures(listOf())
         tile.resource = null
-        tile.changeImprovement(null)
+        tile.removeImprovement()
         tile.setTerrainTransients()
     }
 

core/src/com/unciv/logic/map/mapunit/MapUnit.kt

@@ -648,7 +648,7 @@ class MapUnit : IsPartOfGameInfoSerialization {
     }
 
     private fun clearEncampment(tile: Tile) {
-        tile.changeImprovement(null)
+        tile.removeImprovement()
 
         // Notify City-States that this unit cleared a Barbarian Encampment, required for quests
         civ.gameInfo.getAliveCityStates()
@@ -699,7 +699,7 @@ class MapUnit : IsPartOfGameInfoSerialization {
     }
 
     private fun getAncientRuinBonus(tile: Tile) {
-        tile.changeImprovement(null)
+        tile.removeImprovement()
         civ.ruinsManager.selectNextRuinsReward(this)
     }
 

core/src/com/unciv/logic/map/mapunit/UnitTurnManager.kt

@@ -189,7 +189,7 @@ class UnitTurnManager(val unit: MapUnit) {
                         && !tileImprovement.terrainsCanBeBuiltOn.contains(tile.baseTerrain)
                 ) {
                     // We removed a terrain (e.g. Forest) and the improvement (e.g. Lumber mill) requires it!
-                    tile.changeImprovement(null)
+                    tile.removeImprovement()
                     if (tile.resource != null) unit.civ.cache.updateCivResources() // unlikely, but maybe a mod makes a resource improvement dependent on a terrain feature
                 }
                 if (RoadStatus.values().any { tile.improvementInProgress == it.removeAction }) {

core/src/com/unciv/logic/map/tile/Tile.kt

@@ -308,6 +308,9 @@ open class Tile : IsPartOfGameInfoSerialization {
         else ruleset.tileImprovements[getUnpillagedRoad().name]
     }
 
+    /** Does not remove roads */
+    fun removeImprovement() = changeImprovement(null)
+
     fun changeImprovement(improvementStr: String?) {
         improvementIsPillaged = false
         improvement = improvementStr
@@ -893,7 +896,7 @@ open class Tile : IsPartOfGameInfoSerialization {
         if (resource != null && resource !in ruleset.tileResources)
             resource = null
         if (improvement != null && improvement !in ruleset.tileImprovements)
-            changeImprovement(null)
+            removeImprovement()
     }
 
     /** If the unit isn't in the ruleset we can't even know what type of unit this is! So check each place
@@ -927,7 +930,7 @@ open class Tile : IsPartOfGameInfoSerialization {
         // http://well-of-souls.com/civ/civ5_improvements.html says that naval improvements are destroyed upon pillage
         //    and I can't find any other sources so I'll go with that
         if (!isLand) {
-            changeImprovement(null)
+            removeImprovement()
             owningCity?.reassignPopulationDeferred()
             return
         }
@@ -939,7 +942,7 @@ open class Tile : IsPartOfGameInfoSerialization {
         // if no Repair action, destroy improvements instead
         if (ruleset.tileImprovements[Constants.repair] == null) {
             if (canPillageTileImprovement())
-                changeImprovement(null)
+                removeImprovement()
             else
                 removeRoad()
         } else {

core/src/com/unciv/ui/screens/mapeditorscreen/TileInfoNormalizer.kt

@@ -15,7 +15,7 @@ object TileInfoNormalizer {
                 tile.baseTerrain = tile.getNaturalWonder().turnsInto!!
             tile.setTerrainFeatures(listOf())
             tile.resource = null
-            tile.changeImprovement(null)
+            tile.removeImprovement()
         }
 
         if (!ruleset.terrains.containsKey(tile.baseTerrain))
@@ -47,11 +47,8 @@ object TileInfoNormalizer {
 
     private fun normalizeTileImprovement(tile: Tile, ruleset: Ruleset) {
         val improvementObject = ruleset.tileImprovements[tile.improvement]
-        if (improvementObject == null) {
+        tile.removeImprovement() // Unset, and check if it can be reset. If so, do it, if not, invalid.
-            tile.changeImprovement(null)
+        if (improvementObject == null) return
-            return
-        }
-        tile.changeImprovement(null) // Unset, and check if it can be reset. If so, do it, if not, invalid.
         if (tile.improvementFunctions.canImprovementBeBuiltHere(improvementObject, stateForConditionals = StateForConditionals.IgnoreConditionals))
             tile.changeImprovement(improvementObject.name)
     }

core/src/com/unciv/ui/screens/mapeditorscreen/tabs/MapEditorEditSubTabs.kt

@@ -20,8 +20,8 @@ import com.unciv.ui.audio.MusicMood
 import com.unciv.ui.audio.MusicTrackChooserFlags
 import com.unciv.ui.components.TabbedPager
 import com.unciv.ui.components.extensions.center
-import com.unciv.ui.components.input.onClick
 import com.unciv.ui.components.extensions.toLabel
+import com.unciv.ui.components.input.onClick
 import com.unciv.ui.components.tilegroups.TileGroup
 import com.unciv.ui.components.tilegroups.TileSetStrings
 import com.unciv.ui.images.ImageGetter
@@ -208,7 +208,7 @@ class MapEditorEditImprovementsTab(
         val eraser = FormattedLine("Remove improvement", icon = eraserIcon, size = 32, iconCrossed = true)
         add(eraser.render(0f).apply { onClick {
             editTab.setBrush("Remove improvement", eraserIcon, true) { tile ->
-                tile.changeImprovement(null)
+                tile.removeImprovement()
                 tile.removeRoad()
             }
         } }).padBottom(0f).row()