perf(trie): use Arc for proof sharing and add batch validation

- Wrap DecodedMultiProof and DecodedStorageMultiProof in Arc within ProofResult
  for O(1) cloning when sending batched results to multiple receivers
- Add debug assertions in BatchedStorageProof::merge and BatchedAccountProof::merge
  to validate that all batched jobs share the same Arc for multi_added_removed_keys
  and missed_leaves_storage_roots (critical invariants for correctness)
- Unwrap Arc at extraction sites using try_unwrap for zero-cost when sole owner

crates/trie/parallel/src/proof.rs

@@ -126,7 +126,8 @@ impl ParallelProof {
             )))
         })?;
 
-        // Extract storage proof directly from the result
+        // Extract storage proof directly from the result.
+        // The proof is Arc-wrapped for efficient batch sharing, so we unwrap it here.
         let storage_proof = match proof_msg.result? {
             crate::proof_task::ProofResult::StorageProof { hashed_address: addr, proof } => {
                 debug_assert_eq!(
@@ -134,7 +135,8 @@ impl ParallelProof {
                     hashed_address,
                     "storage worker must return same address: expected {hashed_address}, got {addr}"
                 );
-                proof
+                // Efficiently unwrap Arc: returns inner value if sole owner, clones otherwise.
+                Arc::try_unwrap(proof).unwrap_or_else(|arc| (*arc).clone())
             }
             crate::proof_task::ProofResult::AccountMultiproof { .. } => {
                 unreachable!("storage worker only sends StorageProof variant")
@@ -223,8 +225,12 @@ impl ParallelProof {
             )
         })?;
 
+        // The proof is Arc-wrapped for efficient batch sharing, so we unwrap it here.
         let (multiproof, stats) = match proof_result_msg.result? {
-            crate::proof_task::ProofResult::AccountMultiproof { proof, stats } => (proof, stats),
+            crate::proof_task::ProofResult::AccountMultiproof { proof, stats } => {
+                // Efficiently unwrap Arc: returns inner value if sole owner, clones otherwise.
+                (Arc::try_unwrap(proof).unwrap_or_else(|arc| (*arc).clone()), stats)
+            }
             crate::proof_task::ProofResult::StorageProof { .. } => {
                 unreachable!("account worker only sends AccountMultiproof variant")
             }

crates/trie/parallel/src/proof_task.rs

@@ -116,7 +116,22 @@ impl BatchedStorageProof {
     }
 
     /// Merges another storage proof job into this batch.
+    ///
+    /// # Panics (debug builds only)
+    /// Panics if `input.multi_added_removed_keys` does not point to the same Arc as the batch's.
     fn merge(&mut self, input: StorageProofInput, sender: ProofResultContext) {
+        // Validate that all batched jobs share the same multi_added_removed_keys Arc.
+        // This is a critical invariant: if jobs have different keys, the merged proof
+        // would be computed with only the first job's keys, producing incorrect results.
+        debug_assert!(
+            match (&self.multi_added_removed_keys, &input.multi_added_removed_keys) {
+                (Some(a), Some(b)) => Arc::ptr_eq(a, b),
+                (None, None) => true,
+                _ => false,
+            },
+            "All batched storage proof jobs must share the same multi_added_removed_keys Arc"
+        );
+
         self.prefix_set.extend_keys(input.prefix_set.iter().copied());
         self.target_slots.extend(input.target_slots);
         self.with_branch_node_masks |= input.with_branch_node_masks;
@@ -221,7 +236,31 @@ impl BatchedAccountProof {
     }
 
     /// Merges another account multiproof job into this batch.
+    ///
+    /// # Panics (debug builds only)
+    /// Panics if `input.multi_added_removed_keys` or `input.missed_leaves_storage_roots`
+    /// do not point to the same Arc as the batch's.
     fn merge(&mut self, input: AccountMultiproofInput) {
+        // Validate that all batched jobs share the same multi_added_removed_keys Arc.
+        // This is a critical invariant: if jobs have different keys, the merged proof
+        // would be computed with only the first job's keys, producing incorrect results.
+        debug_assert!(
+            match (&self.multi_added_removed_keys, &input.multi_added_removed_keys) {
+                (Some(a), Some(b)) => Arc::ptr_eq(a, b),
+                (None, None) => true,
+                _ => false,
+            },
+            "All batched account proof jobs must share the same multi_added_removed_keys Arc"
+        );
+
+        // Validate that all batched jobs share the same missed_leaves_storage_roots cache.
+        // This is critical because workers may add entries to this cache during proof computation,
+        // and all receivers expect to see those entries in their shared cache.
+        debug_assert!(
+            Arc::ptr_eq(&self.missed_leaves_storage_roots, &input.missed_leaves_storage_roots),
+            "All batched account proof jobs must share the same missed_leaves_storage_roots Arc"
+        );
+
         // Merge targets.
         self.targets.extend(input.targets);
 
@@ -780,12 +819,16 @@ impl TrieNodeProvider for ProofTaskTrieNodeProvider {
     }
 }
 /// Result of a proof calculation, which can be either an account multiproof or a storage proof.
+///
+/// The proof data is wrapped in `Arc` to enable efficient sharing when batching multiple
+/// proof requests. This avoids expensive cloning of the underlying proof structures
+/// when sending results to multiple receivers.
 #[derive(Debug, Clone)]
 pub enum ProofResult {
     /// Account multiproof with statistics
     AccountMultiproof {
-        /// The account multiproof
-        proof: DecodedMultiProof,
+        /// The account multiproof (Arc-wrapped for efficient sharing in batches)
+        proof: Arc<DecodedMultiProof>,
         /// Statistics collected during proof computation
         stats: ParallelTrieStats,
     },
@@ -793,8 +836,8 @@ pub enum ProofResult {
     StorageProof {
         /// The hashed address this storage proof belongs to
         hashed_address: B256,
-        /// The storage multiproof
-        proof: DecodedStorageMultiProof,
+        /// The storage multiproof (Arc-wrapped for efficient sharing in batches)
+        proof: Arc<DecodedStorageMultiProof>,
     },
 }
 
@@ -803,11 +846,17 @@ impl ProofResult {
     ///
     /// For account multiproofs, returns the multiproof directly (discarding stats).
     /// For storage proofs, wraps the storage proof into a minimal multiproof.
+    ///
+    /// Note: This method clones the inner proof data. If you need to avoid the clone
+    /// when you're the sole owner, consider using `Arc::try_unwrap` first.
     pub fn into_multiproof(self) -> DecodedMultiProof {
         match self {
-            Self::AccountMultiproof { proof, stats: _ } => proof,
+            Self::AccountMultiproof { proof, stats: _ } => {
+                Arc::try_unwrap(proof).unwrap_or_else(|arc| (*arc).clone())
+            }
             Self::StorageProof { hashed_address, proof } => {
-                DecodedMultiProof::from_storage_proof(hashed_address, proof)
+                let storage_proof = Arc::try_unwrap(proof).unwrap_or_else(|arc| (*arc).clone());
+                DecodedMultiProof::from_storage_proof(hashed_address, storage_proof)
             }
         }
     }
@@ -1139,9 +1188,9 @@ where
         let num_senders = senders.len();
         match result {
             Ok(storage_proof) => {
-                // Success case: clone the proof for each sender.
+                // Success case: wrap proof in Arc for efficient sharing across all senders.
                 let proof_result =
-                    ProofResult::StorageProof { hashed_address, proof: storage_proof };
+                    ProofResult::StorageProof { hashed_address, proof: Arc::new(storage_proof) };
 
                 for ProofResultContext { sender, sequence_number, state, start_time } in senders {
                     *storage_proofs_processed += 1;
@@ -1562,8 +1611,8 @@ where
         let num_senders = senders.len();
         match result {
             Ok(proof) => {
-                // Success case: clone the proof for each sender.
-                let proof_result = ProofResult::AccountMultiproof { proof, stats };
+                // Success case: wrap proof in Arc for efficient sharing across all senders.
+                let proof_result = ProofResult::AccountMultiproof { proof: Arc::new(proof), stats };
 
                 for ProofResultContext { sender, sequence_number, state, start_time } in senders {
                     *account_proofs_processed += 1;
@@ -1764,7 +1813,9 @@ where
 
                         drop(_guard);
 
-                        // Extract storage proof from the result
+                        // Extract storage proof from the result.
+                        // The proof is Arc-wrapped for efficient batch sharing, so we unwrap it
+                        // here.
                         let proof = match proof_msg.result? {
                             ProofResult::StorageProof { hashed_address: addr, proof } => {
                                 debug_assert_eq!(
@@ -1772,7 +1823,9 @@ where
                                     hashed_address,
                                     "storage worker must return same address: expected {hashed_address}, got {addr}"
                                 );
-                                proof
+                                // Efficiently unwrap Arc: returns inner value if sole owner, clones
+                                // otherwise.
+                                Arc::try_unwrap(proof).unwrap_or_else(|arc| (*arc).clone())
                             }
                             ProofResult::AccountMultiproof { .. } => {
                                 unreachable!("storage worker only sends StorageProof variant")
@@ -1835,8 +1888,11 @@ where
     // Consume remaining storage proof receivers for accounts not encountered during trie walk.
     for (hashed_address, receiver) in storage_proof_receivers {
         if let Ok(proof_msg) = receiver.recv() {
-            // Extract storage proof from the result
+            // Extract storage proof from the result.
+            // The proof is Arc-wrapped for efficient batch sharing, so we unwrap it here.
             if let Ok(ProofResult::StorageProof { proof, .. }) = proof_msg.result {
+                // Efficiently unwrap Arc: returns inner value if sole owner, clones otherwise.
+                let proof = Arc::try_unwrap(proof).unwrap_or_else(|arc| (*arc).clone());
                 collected_decoded_storages.insert(hashed_address, proof);
             }
         }