Merge pull request #5668 from ethereum-optimism/mark/sdk/migrated-withdrawal-gas

message-utils: use BigNumber

packages/sdk/src/utils/message-utils.ts

@@ -6,13 +6,13 @@ import { LowLevelMessage } from '../interfaces'
 const { hexDataLength } = utils
 
 // Constants used by `CrossDomainMessenger.baseGas`
-const RELAY_CONSTANT_OVERHEAD = 200_000
-const RELAY_PER_BYTE_DATA_COST = 16
-const MIN_GAS_DYNAMIC_OVERHEAD_NUMERATOR = 64
-const MIN_GAS_DYNAMIC_OVERHEAD_DENOMINATOR = 63
-const RELAY_CALL_OVERHEAD = 40_000
-const RELAY_RESERVED_GAS = 40_000
-const RELAY_GAS_CHECK_BUFFER = 5_000
+const RELAY_CONSTANT_OVERHEAD = BigNumber.from(200_000)
+const RELAY_PER_BYTE_DATA_COST = BigNumber.from(16)
+const MIN_GAS_DYNAMIC_OVERHEAD_NUMERATOR = BigNumber.from(64)
+const MIN_GAS_DYNAMIC_OVERHEAD_DENOMINATOR = BigNumber.from(63)
+const RELAY_CALL_OVERHEAD = BigNumber.from(40_000)
+const RELAY_RESERVED_GAS = BigNumber.from(40_000)
+const RELAY_GAS_CHECK_BUFFER = BigNumber.from(5_000)
 
 /**
  * Utility for hashing a LowLevelMessage object.
@@ -62,22 +62,26 @@ export const migratedWithdrawalGasLimit = (
   if (chainID === 420) {
     overhead = BigNumber.from(200_000)
   } else {
+    // Dynamic overhead (EIP-150)
+    // We use a constant 1 million gas limit due to the overhead of simulating all migrated withdrawal
+    // transactions during the migration. This is a conservative estimate, and if a withdrawal
+    // uses more than the minimum gas limit, it will fail and need to be replayed with a higher
+    // gas limit.
+    const dynamicOverhead = MIN_GAS_DYNAMIC_OVERHEAD_NUMERATOR.mul(
+      1_000_000
+    ).div(MIN_GAS_DYNAMIC_OVERHEAD_DENOMINATOR)
+
     // Constant overhead
-    overhead = BigNumber.from(
-      RELAY_CONSTANT_OVERHEAD +
-        // Dynamic overhead (EIP-150)
-        (MIN_GAS_DYNAMIC_OVERHEAD_NUMERATOR * 1_000_000) /
-          MIN_GAS_DYNAMIC_OVERHEAD_DENOMINATOR +
-        // Gas reserved for the worst-case cost of 3/5 of the `CALL` opcode's dynamic gas
-        // factors. (Conservative)
-        RELAY_CALL_OVERHEAD +
-        // Relay reserved gas (to ensure execution of `relayMessage` completes after the
-        // subcontext finishes executing) (Conservative)
-        RELAY_RESERVED_GAS +
-        // Gas reserved for the execution between the `hasMinGas` check and the `CALL`
-        // opcode. (Conservative)
-        RELAY_GAS_CHECK_BUFFER
-    )
+    overhead = RELAY_CONSTANT_OVERHEAD.add(dynamicOverhead)
+      .add(RELAY_CALL_OVERHEAD)
+      // Gas reserved for the worst-case cost of 3/5 of the `CALL` opcode's dynamic gas
+      // factors. (Conservative)
+      // Relay reserved gas (to ensure execution of `relayMessage` completes after the
+      // subcontext finishes executing) (Conservative)
+      .add(RELAY_RESERVED_GAS)
+      // Gas reserved for the execution between the `hasMinGas` check and the `CALL`
+      // opcode. (Conservative)
+      .add(RELAY_GAS_CHECK_BUFFER)
   }
 
   let minGasLimit = dataCost.add(overhead)