Merge pull request #3470 from NomicFoundation/return-data-custom-error

Show return data of unrecognized custom errors

Author: fvictorio

.changeset/warm-radios-cross.md

@@ -0,0 +1,5 @@
+---
+"hardhat": patch
+---
+
+The full return data of unrecognized custom errors is now shown in error messages

packages/hardhat-core/src/internal/hardhat-network/stack-traces/error-inferrer.ts

@@ -519,12 +519,8 @@ export class ErrorInferrer {
       return;
     }
 
-    let errorMessage = "reverted with an unrecognized custom error";
-
-    const selector = returnData.getSelector();
-    if (selector !== undefined) {
-      errorMessage += ` with selector ${selector}`;
-    }
+    const rawReturnData = returnData.value.toString("hex");
+    let errorMessage = `reverted with an unrecognized custom error (return data: 0x${rawReturnData})`;
 
     for (const customError of trace.bytecode.contract.customErrors) {
       if (returnData.matchesSelector(customError.selector)) {

packages/hardhat-core/src/internal/hardhat-network/stack-traces/solidity-errors.ts

@@ -271,16 +271,9 @@ function getMessageFromLastStackTraceEntry(
       }
 
       if (!stackTraceEntry.message.isEmpty()) {
-        const selector = stackTraceEntry.message.getSelector();
+        const returnData = stackTraceEntry.message.value.toString("hex");
 
-        if (selector !== undefined) {
-          return `VM Exception while processing transaction: reverted with an unrecognized custom error with selector ${selector}`;
-        }
-
-        // this should only happen when the transaction has return data but it
-        // has less than 4 bytes, which should be a very uncommon scenario
-        const rawReturnData = stackTraceEntry.message.value.toString("hex");
-        return `VM Exception while processing transaction: reverted with return data ${rawReturnData}`;
+        return `VM Exception while processing transaction: reverted with an unrecognized custom error (return data: 0x${returnData})`;
       }
 
       if (stackTraceEntry.isInvalidOpcodeError) {

packages/hardhat-core/test/internal/hardhat-network/provider/modules/eth/methods/sendTransaction.ts

@@ -420,7 +420,7 @@ describe("Eth module", function () {
                 from: DEFAULT_ACCOUNTS_ADDRESSES[1],
                 data: "0x6080604052348015600f57600080fd5b506040517ffbd8bc9c00000000000000000000000000000000000000000000000000000000815260040160405180910390fdfe",
               },
-              "VM Exception while processing transaction: reverted with an unrecognized custom error with selector fbd8bc9c"
+              "VM Exception while processing transaction: reverted with an unrecognized custom error (return data: 0xfbd8bc9c)"
             );
 
             // This deploys a contract that divides by zero in its contstructor: