Don't apply cramming damage to players (#5903)

patches/server/0729-Don-t-apply-cramming-damage-to-players.patch

@@ -0,0 +1,40 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Phoenix616 <max@themoep.de>
+Date: Sun, 20 Jun 2021 16:35:42 +0100
+Subject: [PATCH] Don't apply cramming damage to players
+
+It does not make a lot of sense to damage players if they get crammed,
+ especially as the usecase of teleporting lots of players to the same
+ location isn't too uncommon and killing all those players isn't
+ really what one would expect to happen.
+
+For those who really want it a config option is provided.
+
+diff --git a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
+index 857ef2377d2e6fd84d70e301860692e670983f0c..171321d4f1b73a25266175dfb5529dfc5cb8a5ca 100644
+--- a/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
++++ b/src/main/java/com/destroystokyo/paper/PaperWorldConfig.java
+@@ -840,5 +840,10 @@ public class PaperWorldConfig {
+     private void showSignClickCommandFailureMessagesToPlayer() {
+         showSignClickCommandFailureMessagesToPlayer = getBoolean("show-sign-click-command-failure-msgs-to-player", showSignClickCommandFailureMessagesToPlayer);
+     }
++
++    public boolean allowPlayerCrammingDamage = false;
++    private void playerCrammingDamage() {
++        allowPlayerCrammingDamage = getBoolean("allow-player-cramming-damage", allowPlayerCrammingDamage);
++    }
+ }
+ 
+diff --git a/src/main/java/net/minecraft/server/level/ServerPlayer.java b/src/main/java/net/minecraft/server/level/ServerPlayer.java
+index 8e2bccc3a9ddb17a4978596056189eb776976338..e32da100eabf0d3de12375402e9378c726811358 100644
+--- a/src/main/java/net/minecraft/server/level/ServerPlayer.java
++++ b/src/main/java/net/minecraft/server/level/ServerPlayer.java
+@@ -1419,7 +1419,7 @@ public class ServerPlayer extends Player {
+ 
+     @Override
+     public boolean isInvulnerableTo(DamageSource damageSource) {
+-        return super.isInvulnerableTo(damageSource) || this.isChangingDimension() || this.getAbilities().invulnerable && damageSource == DamageSource.WITHER;
++        return super.isInvulnerableTo(damageSource) || this.isChangingDimension() || this.getAbilities().invulnerable && damageSource == DamageSource.WITHER || !level.paperConfig.allowPlayerCrammingDamage && damageSource == DamageSource.CRAMMING; // Paper - disable player cramming
+     }
+ 
+     @Override