craftbukkit/nms-patches/net/minecraft/world/damagesource/DamageSource.patch

--- a/net/minecraft/world/damagesource/DamageSource.java
+++ b/net/minecraft/world/damagesource/DamageSource.java
@@ -21,6 +21,119 @@
     private final Entity directEntity;
     @Nullable
     private final Vec3D damageSourcePosition;
+    // CraftBukkit start
+    @Nullable
+    private org.bukkit.block.Block directBlock; // The block that caused the damage. damageSourcePosition is not used for all block damages
+    @Nullable
+    private org.bukkit.block.BlockState directBlockState; // The block state of the block relevant to this damage source
+    private boolean sweep = false;
+    private boolean melting = false;
+    private boolean poison = false;
+    private Entity customEntityDamager = null; // This field is a helper for when direct entity damage is not set by vanilla
+    private Entity customCausingEntityDamager = null; // This field is a helper for when causing entity damage is not set by vanilla
+
+    public DamageSource sweep() {
+        this.sweep = true;
+        return this;
+    }
+
+    public boolean isSweep() {
+        return this.sweep;
+    }
+
+    public DamageSource melting() {
+        this.melting = true;
+        return this;
+    }
+
+    public boolean isMelting() {
+        return this.melting;
+    }
+
+    public DamageSource poison() {
+        this.poison = true;
+        return this;
+    }
+
+    public boolean isPoison() {
+        return this.poison;
+    }
+
+    public Entity getDamager() {
+        return (this.customEntityDamager != null) ? this.customEntityDamager : this.directEntity;
+    }
+
+    public Entity getCausingDamager() {
+        return (this.customCausingEntityDamager != null) ? this.customCausingEntityDamager : this.causingEntity;
+    }
+
+    public DamageSource customEntityDamager(Entity entity) {
+        // This method is not intended for change the causing entity if is already set
+        // also is only necessary if the entity passed is not the direct entity or different from the current causingEntity
+        if (this.customEntityDamager != null || this.directEntity == entity || this.causingEntity == entity) {
+            return this;
+        }
+        DamageSource damageSource = this.cloneInstance();
+        damageSource.customEntityDamager = entity;
+        return damageSource;
+    }
+
+    public DamageSource customCausingEntityDamager(Entity entity) {
+        // This method is not intended for change the causing entity if is already set
+        // also is only necessary if the entity passed is not the direct entity or different from the current causingEntity
+        if (this.customCausingEntityDamager != null || this.directEntity == entity || this.causingEntity == entity) {
+            return this;
+        }
+        DamageSource damageSource = this.cloneInstance();
+        damageSource.customCausingEntityDamager = entity;
+        return damageSource;
+    }
+
+    public org.bukkit.block.Block getDirectBlock() {
+        return this.directBlock;
+    }
+
+    public DamageSource directBlock(net.minecraft.world.level.World world, net.minecraft.core.BlockPosition blockPosition) {
+        if (blockPosition == null || world == null) {
+            return this;
+        }
+        return directBlock(org.bukkit.craftbukkit.block.CraftBlock.at(world, blockPosition));
+    }
+
+    public DamageSource directBlock(org.bukkit.block.Block block) {
+        if (block == null) {
+            return this;
+        }
+        // Cloning the instance lets us return unique instances of DamageSource without affecting constants defined in DamageSources
+        DamageSource damageSource = this.cloneInstance();
+        damageSource.directBlock = block;
+        return damageSource;
+    }
+
+    public org.bukkit.block.BlockState getDirectBlockState() {
+        return this.directBlockState;
+    }
+
+    public DamageSource directBlockState(org.bukkit.block.BlockState blockState) {
+        if (blockState == null) {
+            return this;
+        }
+        // Cloning the instance lets us return unique instances of DamageSource without affecting constants defined in DamageSources
+        DamageSource damageSource = this.cloneInstance();
+        damageSource.directBlockState = blockState;
+        return damageSource;
+    }
+
+    private DamageSource cloneInstance() {
+        DamageSource damageSource = new DamageSource(this.type, this.directEntity, this.causingEntity, this.damageSourcePosition);
+        damageSource.directBlock = this.getDirectBlock();
+        damageSource.directBlockState = this.getDirectBlockState();
+        damageSource.sweep = this.isSweep();
+        damageSource.poison = this.isPoison();
+        damageSource.melting = this.isMelting();
+        return damageSource;
+    }
+    // CraftBukkit end
 
     public String toString() {
         return "DamageSource (" + this.type().msgId() + ")";