Fix TileSet mods can lock user out (#9023)

core/src/com/unciv/UncivGame.kt

@@ -189,7 +189,9 @@ open class UncivGame(val isConsoleMode: Boolean = false) : Game(), PlatformSpeci
 
         ImageGetter.resetAtlases()
         ImageGetter.setNewRuleset(ImageGetter.ruleset)  // This needs to come after the settings, since we may have default visual mods
-        if (settings.tileSet !in ImageGetter.getAvailableTilesets()) { // If one of the tilesets is no longer available, default back
+        val availableTileSets = ImageGetter.getAvailableTilesets().toSet()
+            .intersect(TileSetCache.getAvailableTilesets().toSet())
+        if (settings.tileSet !in availableTileSets) { // If the configured tileset is no longer available, default back
             settings.tileSet = Constants.defaultTileset
         }
 

core/src/com/unciv/models/tilesets/TileSetCache.kt

@@ -80,4 +80,20 @@ object TileSetCache : HashMap<String, TileSet>() {
             set(name, tileset)
         }
     }
+
+    /** Determines potentially available TileSets - by scanning for TileSet jsons.
+     *
+     *  Available before initialization finishes.
+     *  To get more reliable info, either wait until `this` is fully initialized,
+     *  or intersect with [ImageGetter.getAvailableTilesets]
+     */
+    fun getAvailableTilesets() = sequence<FileHandle> {
+        yieldAll(FileHandle("jsons/TileSets").list().asIterable())
+        for (modFolder in FileHandle("mods").list()) {
+            if (!modFolder.isDirectory || modFolder.name().startsWith('.'))
+                continue
+            yieldAll(modFolder.child("jsons/TileSets").list().asIterable())
+        }
+    }.filter { it.exists() }
+    .map { it.nameWithoutExtension().removeSuffix("Config") }
 }

core/src/com/unciv/ui/images/ImageGetter.kt

@@ -448,8 +448,16 @@ object ImageGetter {
 
     fun getAvailableSkins() = ninePatchDrawables.keys.asSequence().map { it.split("/")[1] }.distinct()
 
-    fun getAvailableTilesets() = textureRegionDrawables.keys.asSequence().filter { it.startsWith("TileSets") && !it.contains("/Units/") }
-            .map { it.split("/")[1] }.distinct()
+    /** Determines available TileSets from the currently loaded Texture paths.
+     *
+     *  Note [TileSetCache] will not necessarily load all of them, e.g. if a Mod fails
+     *  to provide a config json for a graphic with a Tileset path.
+     *
+     *  Intersect with [TileSetCache.getAvailableTilesets] for a more reliable answer
+     */
+    fun getAvailableTilesets() = textureRegionDrawables.keys.asSequence()
+        .filter { it.startsWith("TileSets") && !it.contains("/Units/") }
+        .map { it.split("/")[1] }.distinct()
 
     fun getAvailableUnitsets() = textureRegionDrawables.keys.asSequence().filter { it.contains("/Units/") }
         .map { it.split("/")[1] }.distinct()

core/src/com/unciv/ui/screens/mainmenuscreen/MainMenuScreen.kt

@@ -21,6 +21,7 @@ import com.unciv.models.metadata.BaseRuleset
 import com.unciv.models.metadata.GameSetupInfo
 import com.unciv.models.ruleset.Ruleset
 import com.unciv.models.ruleset.RulesetCache
+import com.unciv.models.tilesets.TileSetCache
 import com.unciv.ui.components.AutoScrollPane
 import com.unciv.ui.components.KeyCharAndCode
 import com.unciv.ui.components.UncivTooltip.Companion.addTooltip
@@ -51,6 +52,7 @@ import com.unciv.ui.screens.worldscreen.WorldScreen
 import com.unciv.ui.screens.worldscreen.mainmenu.WorldScreenMenuPopup
 import com.unciv.utils.concurrency.Concurrency
 import com.unciv.utils.concurrency.launchOnGLThread
+import kotlinx.coroutines.CoroutineScope
 import kotlin.math.min
 
 
@@ -104,51 +106,14 @@ class MainMenuScreen: BaseScreen(), RecreateOnResize {
         // will not exist unless we reset the ruleset and images
         ImageGetter.ruleset = RulesetCache.getVanillaRuleset()
 
-        Concurrency.run("ShowMapBackground") {
-            var scale = 1f
-            var mapWidth = stage.width / TileGroupMap.groupHorizontalAdvance
-            var mapHeight = stage.height / TileGroupMap.groupSize
-            if (mapWidth * mapHeight > 3000f) {  // 3000 as max estimated number of tiles is arbitrary (we had typically 721 before)
-                scale = mapWidth * mapHeight / 3000f
-                mapWidth /= scale
-                mapHeight /= scale
-                scale = min(scale, 20f)
+        // This is an extreme safeguard - should an invalid settings.tileSet ever make it past the
+        // guard in UncivGame.create, simply omit the background so the user can at least get to options
+        // (let him crash when loading a game but avoid locking him out entirely)
+        if (game.settings.tileSet in TileSetCache)
+            Concurrency.run("ShowMapBackground") {
+                showMapBackground()
             }
 
-            val baseRuleset = RulesetCache.getVanillaRuleset()
-            easterEggRuleset = EasterEggRulesets.getTodayEasterEggRuleset()?.let {
-                RulesetCache.getComplexRuleset(baseRuleset, listOf(it))
-            }
-            val mapRuleset = if (game.settings.enableEasterEggs) easterEggRuleset ?: baseRuleset else baseRuleset
-
-            val newMap = MapGenerator(mapRuleset)
-                    .generateMap(MapParameters().apply {
-                        shape = MapShape.rectangular
-                        mapSize = MapSizeNew(MapSize.Small)
-                        type = MapType.pangaea
-                        temperatureExtremeness = .7f
-                        waterThreshold = -0.1f // mainly land, gets about 30% water
-                        modifyForEasterEgg()
-                    })
-
-            launchOnGLThread { // for GL context
-                ImageGetter.setNewRuleset(mapRuleset)
-                val mapHolder = EditorMapHolder(
-                    this@MainMenuScreen,
-                    newMap
-                ) {}
-                mapHolder.setScale(scale)
-                backgroundTable.addAction(Actions.sequence(
-                        Actions.fadeOut(0f),
-                        Actions.run {
-                            backgroundTable.addActor(mapHolder)
-                            mapHolder.center(backgroundTable)
-                        },
-                        Actions.fadeIn(0.3f)
-                ))
-            }
-        }
-
         val column1 = Table().apply { defaults().pad(10f).fillX() }
         val column2 = if (singleColumn) column1 else Table().apply { defaults().pad(10f).fillX() }
 
@@ -220,6 +185,50 @@ class MainMenuScreen: BaseScreen(), RecreateOnResize {
         stage.addActor(helpButton)
     }
 
+    private fun CoroutineScope.showMapBackground() {
+        var scale = 1f
+        var mapWidth = stage.width / TileGroupMap.groupHorizontalAdvance
+        var mapHeight = stage.height / TileGroupMap.groupSize
+        if (mapWidth * mapHeight > 3000f) {  // 3000 as max estimated number of tiles is arbitrary (we had typically 721 before)
+            scale = mapWidth * mapHeight / 3000f
+            mapWidth /= scale
+            mapHeight /= scale
+            scale = min(scale, 20f)
+        }
+
+        val baseRuleset = RulesetCache.getVanillaRuleset()
+        easterEggRuleset = EasterEggRulesets.getTodayEasterEggRuleset()?.let {
+            RulesetCache.getComplexRuleset(baseRuleset, listOf(it))
+        }
+        val mapRuleset = if (game.settings.enableEasterEggs) easterEggRuleset ?: baseRuleset else baseRuleset
+
+        val newMap = MapGenerator(mapRuleset)
+            .generateMap(MapParameters().apply {
+                shape = MapShape.rectangular
+                mapSize = MapSizeNew(MapSize.Small)
+                type = MapType.pangaea
+                temperatureExtremeness = 0.7f
+                waterThreshold = -0.1f // mainly land, gets about 30% water
+                modifyForEasterEgg()
+            })
+
+        launchOnGLThread { // for GL context
+            ImageGetter.setNewRuleset(mapRuleset)
+            val mapHolder = EditorMapHolder(
+                this@MainMenuScreen,
+                newMap
+            ) {}
+            mapHolder.setScale(scale)
+            backgroundTable.addAction(Actions.sequence(
+                Actions.fadeOut(0f),
+                Actions.run {
+                    backgroundTable.addActor(mapHolder)
+                    mapHolder.center(backgroundTable)
+                },
+                Actions.fadeIn(0.3f)
+            ))
+        }
+    }
 
     private fun resumeGame() {
         if (GUI.isWorldLoaded()) {