Paper/patches/server/0402-Fix-some-rails-connecting-improperly.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Spottedleaf <Spottedleaf@users.noreply.github.com>
Date: Fri, 24 Jul 2020 15:56:05 -0700
Subject: [PATCH] Fix some rails connecting improperly


diff --git a/src/main/java/net/minecraft/world/level/block/BaseRailBlock.java b/src/main/java/net/minecraft/world/level/block/BaseRailBlock.java
index f9b6db516fa0788a6d4d40fa7ea2039cd3282b24..0961f6f5e627debe0bf02670d922e6d3388ba631 100644
--- a/src/main/java/net/minecraft/world/level/block/BaseRailBlock.java
+++ b/src/main/java/net/minecraft/world/level/block/BaseRailBlock.java
@@ -68,6 +68,7 @@ public abstract class BaseRailBlock extends Block implements SimpleWaterloggedBl
         state = this.updateDir(world, pos, state, true);
         if (this.isStraight) {
             world.neighborChanged(state, pos, this, pos, notify);
+            state = world.getBlockState(pos); // Paper - Fix some rails connecting improperly
         }
 
         return state;
diff --git a/src/main/java/net/minecraft/world/level/block/DetectorRailBlock.java b/src/main/java/net/minecraft/world/level/block/DetectorRailBlock.java
index e5534fd35a8f9736cc25471e9f0feaa8da88c85d..55a97da8786ec0ae98abe56876c00f4678ba0007 100644
--- a/src/main/java/net/minecraft/world/level/block/DetectorRailBlock.java
+++ b/src/main/java/net/minecraft/world/level/block/DetectorRailBlock.java
@@ -77,6 +77,7 @@ public class DetectorRailBlock extends BaseRailBlock {
 
     private void checkPressed(Level world, BlockPos pos, BlockState state) {
         if (this.canSurvive(state, world, pos)) {
+            if (state.getBlock() != this) { return; } // Paper - Fix some rails connecting improperly
             boolean flag = (Boolean) state.getValue(DetectorRailBlock.POWERED);
             boolean flag1 = false;
             List<AbstractMinecart> list = this.getInteractingMinecartOfType(world, pos, AbstractMinecart.class, (entity) -> {
diff --git a/src/main/java/net/minecraft/world/level/block/RailState.java b/src/main/java/net/minecraft/world/level/block/RailState.java
index 6caafa73b03ed55c95303e49735eaf3dfd34903a..aa7ebaccad8dc555d9e1dee300e75fcd968a3608 100644
--- a/src/main/java/net/minecraft/world/level/block/RailState.java
+++ b/src/main/java/net/minecraft/world/level/block/RailState.java
@@ -17,6 +17,12 @@ public class RailState {
     private final boolean isStraight;
     private final List<BlockPos> connections = Lists.newArrayList();
 
+    // Paper start - Fix some rails connecting improperly
+    public boolean isValid() {
+        return this.level.getBlockState(this.pos).getBlock() == this.state.getBlock();
+    }
+    // Paper end - Fix some rails connecting improperly
+
     public RailState(Level world, BlockPos pos, BlockState state) {
         this.level = world;
         this.pos = pos;
@@ -141,6 +147,11 @@ public class RailState {
     }
 
     private void connectTo(RailState placementHelper) {
+        // Paper start - Fix some rails connecting improperly
+        if (!this.isValid() || !placementHelper.isValid()) {
+            return;
+        }
+        // Paper end - Fix some rails connecting improperly
         this.connections.add(placementHelper.pos);
         BlockPos blockPos = this.pos.north();
         BlockPos blockPos2 = this.pos.south();
@@ -331,10 +342,15 @@ public class RailState {
         this.state = this.state.setValue(this.block.getShapeProperty(), railShape2);
         if (forceUpdate || this.level.getBlockState(this.pos) != this.state) {
             this.level.setBlock(this.pos, this.state, 3);
+            // Paper start - Fix some rails connecting improperly
+            if (!this.isValid()) {
+                return this;
+            }
+            // Paper end - Fix some rails connecting improperly
 
             for (int i = 0; i < this.connections.size(); i++) {
                 RailState railState = this.getRail(this.connections.get(i));
-                if (railState != null) {
+                if (railState != null && railState.isValid()) { // Paper - Fix some rails connecting improperly
                     railState.removeSoftConnections();
                     if (railState.canConnectTo(this)) {
                         railState.connectTo(this);
@@ -347,6 +363,6 @@ public class RailState {
     }
 
     public BlockState getState() {
-        return this.state;
+        return this.level.getBlockState(this.pos); // Paper - Fix some rails connecting improperly
     }
 }