Prevent softlocked end exit portal generation (#6525)

patches/server/0803-Prevent-softlocked-end-exit-portal-generation.patch

@@ -0,0 +1,23 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Noah van der Aa <ndvdaa@gmail.com>
+Date: Mon, 30 Aug 2021 15:22:18 +0200
+Subject: [PATCH] Prevent softlocked end exit portal generation
+
+
+diff --git a/src/main/java/net/minecraft/world/level/dimension/end/EndDragonFight.java b/src/main/java/net/minecraft/world/level/dimension/end/EndDragonFight.java
+index 93dd5a2d0b550b0373cbf59376a04e9fd6146e92..3cdd3778e8d55bc255a4b6f248b80c04ef0c5ad1 100644
+--- a/src/main/java/net/minecraft/world/level/dimension/end/EndDragonFight.java
++++ b/src/main/java/net/minecraft/world/level/dimension/end/EndDragonFight.java
+@@ -409,6 +409,12 @@ public class EndDragonFight {
+             }
+         }
+ 
++        // Paper start - Prevent "softlocked" exit portal generation
++        if (this.portalLocation.getY() <= this.level.getMinBuildHeight()) {
++            this.portalLocation.setY(this.level.getMinBuildHeight() + 1);
++        }
++        // Paper end
++
+         endPodiumFeature.configured(FeatureConfiguration.NONE).place(this.level, this.level.getChunkSource().getGenerator(), new Random(), this.portalLocation);
+     }
+