PaperMC/paper-server/patches/sources/net/minecraft/server/level/WorldGenRegion.java.patch

--- a/net/minecraft/server/level/WorldGenRegion.java
+++ b/net/minecraft/server/level/WorldGenRegion.java
@@ -217,7 +217,7 @@
         if (iblockdata.isAir()) {
             return false;
         } else {
-            if (drop) {
+            if (false) { // CraftBukkit - SPIGOT-6833: Do not drop during world generation
                 BlockEntity tileentity = iblockdata.hasBlockEntity() ? this.getBlockEntity(pos) : null;
 
                 Block.dropResources(iblockdata, this.level, pos, tileentity, breakingEntity, ItemStack.EMPTY);
@@ -336,6 +336,13 @@
 
     @Override
     public boolean addFreshEntity(Entity entity) {
+        // CraftBukkit start
+        return this.addFreshEntity(entity, org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason.DEFAULT);
+    }
+
+    @Override
+    public boolean addFreshEntity(Entity entity, org.bukkit.event.entity.CreatureSpawnEvent.SpawnReason reason) {
+        // CraftBukkit end
         int i = SectionPos.blockToSectionCoord(entity.getBlockX());
         int j = SectionPos.blockToSectionCoord(entity.getBlockZ());