Feat/blocksimulate endpoint

docs/rpc/openapi.yaml

@@ -2238,3 +2238,48 @@ paths:
           $ref: "#/components/responses/NotFound"
         "500":
           $ref: "#/components/responses/InternalServerError"
+
+  /v3/blocks/simulate/{block_id}:
+    get:
+      summary: Simulate mining of a block with the specified transactions and returns its content
+      tags:
+        - Blocks
+      security:
+        - rpcAuth: []
+      operationId: blockSimulate
+      description: |
+        Simulate the mining of a block (no data is written in the MARF) with specified trnsactions and returns its content.
+      parameters:
+        - name: block_id
+          in: path
+          description: The block ID hash
+          required: true
+          schema:
+            type: string
+            pattern: "^[0-9a-f]{64}$"
+      requestBody:
+        required: true
+        content:
+          application/json:
+            schema:
+              type: array
+              items:
+                type: string
+                description: SIP-003-encoded Transaction in hex format
+      responses:
+        "200":
+          description: Content of the simulated block
+          content:
+            application/json:
+              schema:
+                $ref: "#/components/schemas/BlockReplay"
+              example:
+                $ref: "./components/examples/block-replay.example.json"
+        "400":
+          $ref: "#/components/responses/BadRequest"
+        "401":
+          $ref: "#/components/responses/Unauthorized"
+        "404":
+          $ref: "#/components/responses/NotFound"
+        "500":
+          $ref: "#/components/responses/InternalServerError"

stackslib/src/chainstate/stacks/db/mod.rs

@@ -606,6 +606,10 @@ impl<'a, 'b> ClarityTx<'a, 'b> {
             })
             .expect("FATAL: `ust-liquid-supply` overflowed");
     }
+
+    pub fn disable_fees(&mut self) {
+        self.block.no_fees = true;
+    }
 }
 
 pub struct ChainstateTx<'a> {

stackslib/src/chainstate/stacks/db/transactions.rs

@@ -564,6 +564,7 @@ impl StacksChainState {
         }
 
         StacksChainState::account_debit(clarity_tx, &payer_account.principal, fee);
+
         Ok(fee)
     }
 
@@ -1568,6 +1569,8 @@ impl StacksChainState {
         debug!("Process transaction {} ({})", tx.txid(), tx.payload.name());
         let epoch = clarity_block.get_epoch();
 
+        let no_fees = clarity_block.block.no_fees;
+
         StacksChainState::process_transaction_precheck(&clarity_block.config, tx, epoch)?;
 
         // what version of Clarity did the transaction caller want? And, is it valid now?
@@ -1592,7 +1595,10 @@ impl StacksChainState {
 
             let payer_address = payer_account.principal.clone();
             let payer_nonce = payer_account.nonce;
-            StacksChainState::pay_transaction_fee(&mut transaction, fee, payer_account)?;
+
+            if !no_fees {
+                StacksChainState::pay_transaction_fee(&mut transaction, fee, payer_account)?;
+            }
 
             // origin balance may have changed (e.g. if the origin paid the tx fee), so reload the account
             let origin_account =
@@ -1633,8 +1639,10 @@ impl StacksChainState {
                 None,
             )?;
 
-            let new_payer_account = StacksChainState::get_payer_account(&mut transaction, tx);
-            StacksChainState::pay_transaction_fee(&mut transaction, fee, new_payer_account)?;
+            if !no_fees {
+                let new_payer_account = StacksChainState::get_payer_account(&mut transaction, tx);
+                StacksChainState::pay_transaction_fee(&mut transaction, fee, new_payer_account)?;
+            }
 
             // update the account nonces
             StacksChainState::update_account_nonce(

stackslib/src/clarity_vm/clarity.rs

@@ -117,6 +117,7 @@ pub struct ClarityBlockConnection<'a, 'b> {
     mainnet: bool,
     chain_id: u32,
     epoch: StacksEpochId,
+    pub no_fees: bool,
 }
 
 ///
@@ -318,6 +319,7 @@ impl ClarityBlockConnection<'_, '_> {
             mainnet: false,
             chain_id: CHAIN_ID_TESTNET,
             epoch,
+            no_fees: false,
         }
     }
 
@@ -444,6 +446,7 @@ impl ClarityInstance {
             mainnet: self.mainnet,
             chain_id: self.chain_id,
             epoch: epoch.epoch_id,
+            no_fees: false,
         }
     }
 
@@ -468,6 +471,7 @@ impl ClarityInstance {
             mainnet: self.mainnet,
             chain_id: self.chain_id,
             epoch,
+            no_fees: false,
         }
     }
 
@@ -494,6 +498,7 @@ impl ClarityInstance {
             mainnet: self.mainnet,
             chain_id: self.chain_id,
             epoch,
+            no_fees: false,
         };
 
         let use_mainnet = self.mainnet;
@@ -590,6 +595,7 @@ impl ClarityInstance {
             mainnet: self.mainnet,
             chain_id: self.chain_id,
             epoch,
+            no_fees: false,
         };
 
         let use_mainnet = self.mainnet;
@@ -698,6 +704,7 @@ impl ClarityInstance {
             mainnet: self.mainnet,
             chain_id: self.chain_id,
             epoch: epoch.epoch_id,
+            no_fees: false,
         }
     }
 
@@ -738,6 +745,7 @@ impl ClarityInstance {
             mainnet: self.mainnet,
             chain_id: self.chain_id,
             epoch: epoch.epoch_id,
+            no_fees: false,
         }
     }