From 666c2056f359273182c761a10948ce4da4d9c80d Mon Sep 17 00:00:00 2001
From: yairm210 <yairm210@hotmail.com>
Date: Wed, 6 Aug 2025 09:55:52 +0300
Subject: [PATCH] Bugfix: Building 'improvement to create' no longer cached
 across rulesets

---
 core/src/com/unciv/models/ruleset/Building.kt | 24 ++++++++-----------
 .../unciv/models/ruleset/unique/UniqueType.kt |  3 ++-
 2 files changed, 12 insertions(+), 15 deletions(-)

diff --git a/core/src/com/unciv/models/ruleset/Building.kt b/core/src/com/unciv/models/ruleset/Building.kt
index a6fedff8bf..b6a429f256 100644
--- a/core/src/com/unciv/models/ruleset/Building.kt
+++ b/core/src/com/unciv/models/ruleset/Building.kt
@@ -529,24 +529,20 @@ class Building : RulesetStatsObject(), INonPerpetualConstruction {
     }
 
     // This can be 'by lazy' across all rulesets because it only checks building uniques
-    private val _hasCreatesOneImprovementUnique by lazy {
-        hasUnique(UniqueType.CreatesOneImprovement)
+    private val improvementToCreate: String? by lazy { 
+        val unique = getMatchingUniques(UniqueType.CreatesOneImprovement).firstOrNull()
+        if (unique == null) null
+        else unique.params[0]
     }
-    @Readonly fun hasCreateOneImprovementUnique() = _hasCreatesOneImprovementUnique
-
-    @Cache private var _getImprovementToCreate: TileImprovement? = null
     
+    @Readonly fun hasCreateOneImprovementUnique() = improvementToCreate != null
+
     @Readonly
-    // This CANNOT be cached across rulesets, because the improvement itself is retrieved. Currently a bug!
-    // TODO: Clean up - retrieve only the *name* of the improvement
+    // Only the name can be cached across rulesets.
+    // The improvement itself CANNOT be cached because it's ruleset-dependent.
     private fun getImprovementToCreate(ruleset: Ruleset): TileImprovement? {
-        if (!hasCreateOneImprovementUnique()) return null
-        if (_getImprovementToCreate == null) {
-            val improvementUnique = getMatchingUniques(UniqueType.CreatesOneImprovement)
-                .firstOrNull() ?: return null
-            _getImprovementToCreate = ruleset.tileImprovements[improvementUnique.params[0]]
-        }
-        return _getImprovementToCreate
+        if (improvementToCreate == null) return null
+        return ruleset.tileImprovements[improvementToCreate]
     }
     
     @Readonly
diff --git a/core/src/com/unciv/models/ruleset/unique/UniqueType.kt b/core/src/com/unciv/models/ruleset/unique/UniqueType.kt
index 824c8d1377..e98858ca3a 100644
--- a/core/src/com/unciv/models/ruleset/unique/UniqueType.kt
+++ b/core/src/com/unciv/models/ruleset/unique/UniqueType.kt
@@ -360,7 +360,8 @@ enum class UniqueType(
 
     CreatesOneImprovement("Creates a [improvementName] improvement on a specific tile", UniqueTarget.Building,
         docDescription = "When choosing to construct this building, the player must select a tile where the improvement can be built." +
-                " Upon building completion, the tile will gain this improvement."),
+                " Upon building completion, the tile will gain this improvement." + 
+                " Limited to one per building."),
     //endregion
 
     ///////////////////////////////////////// region 04 UNIT UNIQUES /////////////////////////////////////////