Fix player placed rails trying to connect to partially connected stra…

…ight rails

gradle.properties

@@ -8,6 +8,6 @@ minecraft_version=1.17
 loader_version=0.16.9
 
 # Mod Properties
-mod_version=1.0.0
+mod_version=1.1.0
 maven_group=no2.railplacementfix
 archives_base_name=rail-placement-fix

src/main/java/no2/railplacementfix/RailPlacementFix.java

@@ -13,7 +13,9 @@ public class RailPlacementFix implements ModInitializer {
 	// That way, it's clear which mod wrote info, warnings, and errors.
 	public static final Logger LOGGER = LoggerFactory.getLogger(MOD_ID);
 
-	@Override
+	public static boolean EXPERIMENTAL_FEATURES = true;
+
+    @Override
 	public void onInitialize() {
 		// This code runs as soon as Minecraft is in a mod-load-ready state.
 		// However, some things (like resources) may still be uninitialized.

src/main/java/no2/railplacementfix/common/RailPlacementHelper.java

@@ -4,5 +4,5 @@
 
 public class RailPlacementHelper {
     public static final ThreadLocal<BlockPos> NO_CONNECT_POS = new ThreadLocal<>();
-
+    public static final ThreadLocal<BlockPos> PLAYER_PLACED_POS = new ThreadLocal<>();
 }

src/main/java/no2/railplacementfix/mixin/BaseRailBlockMixin.java

@@ -11,7 +11,6 @@
 import net.minecraft.world.level.block.state.properties.BooleanProperty;
 import net.minecraft.world.level.block.state.properties.Property;
 import net.minecraft.world.level.block.state.properties.RailShape;
-import net.minecraft.world.level.material.FluidState;
 import net.minecraft.world.phys.Vec3;
 import org.jetbrains.annotations.Nullable;
 import org.spongepowered.asm.mixin.Final;
@@ -25,6 +24,7 @@
 import org.spongepowered.asm.mixin.injection.callback.LocalCapture;
 
 import static no2.railplacementfix.common.RailPlacementHelper.NO_CONNECT_POS;
+import static no2.railplacementfix.common.RailPlacementHelper.PLAYER_PLACED_POS;
 
 @Mixin(BaseRailBlock.class)
 public abstract class BaseRailBlockMixin extends Block implements SimpleWaterloggedBlock {
@@ -48,8 +48,9 @@ public BaseRailBlockMixin(Properties properties) {
     ), cancellable = true, locals = LocalCapture.CAPTURE_FAILHARD
     )
     private void getSmartPlacementState(BlockPlaceContext blockPlaceContext, CallbackInfoReturnable<BlockState> cir, boolean shouldWaterlog, BlockState defaultRailState, Direction placementDirection) {
+        BlockPos blockPos = blockPlaceContext.getClickedPos();
+        PLAYER_PLACED_POS.set(blockPos);
         if (blockPlaceContext.getPlayer() != null && blockPlaceContext.getPlayer().isShiftKeyDown()) {
-            BlockPos blockPos = blockPlaceContext.getClickedPos();
             Direction clickSide = blockPlaceContext.getClickedFace();
 
             Vec3 clickLocation = blockPlaceContext.getClickLocation();
@@ -127,12 +128,14 @@ private BlockState cancelUpdates(BaseRailBlock instance, Level level, BlockPos b
         BlockPos noUpdatePos = NO_CONNECT_POS.get();
 
         if (noUpdatePos != null) {
-            NO_CONNECT_POS.set(null);
+            NO_CONNECT_POS.remove();
         }
 
         if (!blockPos.equals(noUpdatePos)) {
             return this.updateDir(level, blockPos, blockState, bl);
         }
+        PLAYER_PLACED_POS.remove();
+
         return blockState;
     }
 }

src/main/java/no2/railplacementfix/mixin/RailStateMixin.java

@@ -0,0 +1,49 @@
+package no2.railplacementfix.mixin;
+
+import net.minecraft.core.BlockPos;
+import net.minecraft.world.level.block.RailState;
+import no2.railplacementfix.RailPlacementFix;
+import no2.railplacementfix.common.RailPlacementHelper;
+import org.spongepowered.asm.mixin.Final;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.Shadow;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
+
+import java.util.List;
+
+@Mixin(RailState.class)
+public abstract class RailStateMixin {
+
+    @Shadow protected abstract boolean connectsTo(RailState railState);
+
+    @Shadow @Final private List<BlockPos> connections;
+
+    @Shadow @Final private boolean isStraight;
+
+    @Shadow public abstract List<BlockPos> getConnections();
+
+    @Shadow @Final private BlockPos pos;
+
+
+    @Inject(
+            method = "canConnectTo",
+            at = @At(
+                    value = "INVOKE",
+                    target = "Ljava/util/List;size()I"
+            ), cancellable = true
+    )
+    private void canConnectTo(RailState railState, CallbackInfoReturnable<Boolean> cir) {
+        BlockPos neighborPos = ((RailStateMixin) (Object) railState).pos;
+        if (neighborPos.equals(RailPlacementHelper.PLAYER_PLACED_POS.get()) && this.isStraight) {
+            if (this.connections.size() == 1) {
+                BlockPos possible_connection = this.pos.offset(this.pos.subtract(this.connections.get(0)));
+                if (neighborPos.getX() != (possible_connection.getX()) ||
+                        neighborPos.getZ() != (possible_connection.getZ())) {
+                    cir.setReturnValue(false);
+                }
+            }
+        }
+    }
+}

src/main/resources/rail-placement-fix.mixins.json

@@ -1,10 +1,11 @@
 {
-	"required": true,
-	"package": "no2.railplacementfix.mixin",
-	"mixins": [
-		"BaseRailBlockMixin"
-	],
-	"injectors": {
-		"defaultRequire": 1
+  "required": true,
+  "package": "no2.railplacementfix.mixin",
+  "mixins": [
+    "BaseRailBlockMixin",
+    "RailStateMixin"
+  ],
+  "injectors": {
+    "defaultRequire": 1
 	}
 }