refactor: Prefer injection over arg at construct time

This gives a more granular access and doesn't require the callers to
necessarily be concerned with details they might not be interested in.

Author: Xanewok

packages/hardhat-core/src/internal/hardhat-network/provider/provider.ts

@@ -167,6 +167,9 @@ export class EdrProviderWrapper
   // temporarily added to make smock work with HH+EDR
   private _callOverrideCallback?: CallOverrideCallback;
 
+  /** Used for internal stack trace tests. */
+  private _vmTracer?: VMTracer;
+
   private constructor(
     private readonly _provider: EdrProviderT,
     // we add this for backwards-compatibility with plugins like solidity-coverage
@@ -175,7 +178,6 @@ export class EdrProviderWrapper
     },
     private readonly _eventAdapter: EdrProviderEventAdapter,
     private readonly _vmTraceDecoder: VmTraceDecoder,
-    private readonly _vmTracer: VMTracer | undefined,
     // The common configuration for EthereumJS VM is not used by EDR, but tests expect it as part of the provider.
     private readonly _common: Common,
     tracingConfig?: TracingConfig
@@ -190,8 +192,7 @@ export class EdrProviderWrapper
   public static async create(
     config: HardhatNetworkProviderConfig,
     loggerConfig: LoggerConfig,
-    tracingConfig?: TracingConfig,
-    vmTracer?: VMTracer
+    tracingConfig?: TracingConfig
   ): Promise<EdrProviderWrapper> {
     const { Provider } = requireNapiRsModule(
       "@nomicfoundation/edr"
@@ -316,7 +317,6 @@ export class EdrProviderWrapper
       minimalEthereumJsNode,
       eventAdapter,
       vmTraceDecoder,
-      vmTracer,
       common,
       tracingConfig
     );
@@ -468,9 +468,13 @@ export class EdrProviderWrapper
     }
   }
 
-  /** Used for internal stack traces integration tests. Only defined there. */
-  public vmTracer(): VMTracer | undefined {
-    return this._vmTracer;
+  /**
+   * Injects a `VMTracer` that observes EVM throughout requests.
+   *
+   * Used for internal stack traces integration tests.
+   */
+  public injectVmTracer(vmTracer?: VMTracer) {
+    this._vmTracer = vmTracer;
   }
 
   // temporarily added to make smock work with HH+EDR

packages/hardhat-core/src/internal/hardhat-network/stack-traces/vm-tracer.ts

@@ -46,10 +46,6 @@ export class VMTracer {
     return this._lastError;
   }
 
-  public clearLastError() {
-    this._lastError = undefined;
-  }
-
   private _shouldKeepTracing() {
     return this._throwErrors || this._lastError === undefined;
   }

packages/hardhat-core/test/internal/hardhat-network/stack-traces/execution.ts

@@ -1,5 +1,3 @@
-import { assert } from "chai";
-
 import {
   bigIntToHex,
   bytesToHex,
@@ -60,8 +58,7 @@ export async function instantiateProvider(
   const provider = await EdrProviderWrapper.create(
     config,
     loggerConfig,
-    tracingConfig,
-    new VMTracer(false)
+    tracingConfig
   );
 
   return provider;
@@ -108,10 +105,8 @@ export async function traceTransaction(
   provider: EdrProviderWrapper,
   txData: TxData
 ): Promise<MessageTrace> {
-  const vmTracer = provider.vmTracer();
-  if (vmTracer === undefined) {
-    assert.fail("VMTracer should always be initialized in stack-traces");
-  }
+  const vmTracer = new VMTracer(false);
+  provider.injectVmTracer(vmTracer);
 
   try {
     await provider.request({
@@ -136,6 +131,6 @@ export async function traceTransaction(
     }
     return trace;
   } finally {
-    vmTracer.clearLastError();
+    provider.injectVmTracer(undefined);
   }
 }