fix(NODE-3810): delay timeout errors by one event loop tick

.gitignore

@@ -77,4 +77,4 @@ etc/docs/build
 !docs/*/lib
 !docs/**/*.png
 !docs/**/*.css
-!docs/**/*.js
+!docs/**/*.js

src/cmap/commands.ts

@@ -458,6 +458,7 @@ export class KillCursor {
   }
 }
 
+/** @internal */
 export interface MessageHeader {
   length: number;
   requestId: number;
@@ -466,6 +467,7 @@ export interface MessageHeader {
   fromCompressed?: boolean;
 }
 
+/** @internal */
 export interface OpResponseOptions extends BSONSerializeOptions {
   raw?: boolean;
   documentsReturnedIn?: string | null;
@@ -640,6 +642,7 @@ const OPTS_CHECKSUM_PRESENT = 1;
 const OPTS_MORE_TO_COME = 2;
 const OPTS_EXHAUST_ALLOWED = 1 << 16;
 
+/** @internal */
 export interface OpMsgOptions {
   requestId: number;
   serializeFunctions: boolean;

src/cmap/connection.ts

@@ -75,6 +75,8 @@ const kHello = Symbol('hello');
 const kAutoEncrypter = Symbol('autoEncrypter');
 /** @internal */
 const kFullResult = Symbol('fullResult');
+/** @internal */
+const kDelayedTimeoutId = Symbol('delayedTimeoutId');
 
 /** @internal */
 export interface QueryOptions extends BSONSerializeOptions {
@@ -191,6 +193,9 @@ export class Connection extends TypedEventEmitter<ConnectionEvents> {
   lastHelloMS?: number;
   serverApi?: ServerApi;
   helloOk?: boolean;
+
+  /**@internal */
+  [kDelayedTimeoutId]: NodeJS.Timeout | null;
   /** @internal */
   [kDescription]: StreamDescription;
   /** @internal */
@@ -245,19 +250,21 @@ export class Connection extends TypedEventEmitter<ConnectionEvents> {
       ...options,
       maxBsonMessageSize: this.hello?.maxBsonMessageSize
     });
-    this[kMessageStream].on('message', messageHandler(this));
     this[kStream] = stream;
-    stream.on('error', () => {
+
+    this[kDelayedTimeoutId] = null;
+
+    this[kMessageStream].on('message', message => this.onMessage(message));
+    this[kMessageStream].on('error', error => this.onError(error));
+    this[kStream].on('close', () => this.onClose());
+    this[kStream].on('timeout', () => this.onTimeout());
+    this[kStream].on('error', () => {
       /* ignore errors, listen to `close` instead */
     });
 
-    this[kMessageStream].on('error', error => this.handleIssue({ destroy: error }));
-    stream.on('close', () => this.handleIssue({ isClose: true }));
-    stream.on('timeout', () => this.handleIssue({ isTimeout: true, destroy: true }));
-
     // hook the message stream up to the passed in stream
-    stream.pipe(this[kMessageStream]);
-    this[kMessageStream].pipe(stream);
+    this[kStream].pipe(this[kMessageStream]);
+    this[kMessageStream].pipe(this[kStream]);
   }
 
   get description(): StreamDescription {
@@ -309,40 +316,133 @@ export class Connection extends TypedEventEmitter<ConnectionEvents> {
     this[kLastUseTime] = now();
   }
 
-  handleIssue(issue: { isTimeout?: boolean; isClose?: boolean; destroy?: boolean | Error }): void {
+  onError(error: Error) {
     if (this.closed) {
       return;
     }
 
-    if (issue.destroy) {
-      this[kStream].destroy(typeof issue.destroy === 'boolean' ? undefined : issue.destroy);
+    this[kStream].destroy(error);
+
+    this.closed = true;
+
+    for (const op of this[kQueue].values()) {
+      op.cb(error);
+    }
+
+    this[kQueue].clear();
+    this.emit(Connection.CLOSE);
+  }
+
+  onClose() {
+    if (this.closed) {
+      return;
     }
 
     this.closed = true;
 
-    for (const [, op] of this[kQueue]) {
-      if (issue.isTimeout) {
-        op.cb(
-          new MongoNetworkTimeoutError(`connection ${this.id} to ${this.address} timed out`, {
-            beforeHandshake: this.hello == null
-          })
-        );
-      } else if (issue.isClose) {
-        op.cb(new MongoNetworkError(`connection ${this.id} to ${this.address} closed`));
-      } else {
-        op.cb(typeof issue.destroy === 'boolean' ? undefined : issue.destroy);
-      }
+    const message = `connection ${this.id} to ${this.address} closed`;
+    for (const op of this[kQueue].values()) {
+      op.cb(new MongoNetworkError(message));
     }
 
     this[kQueue].clear();
     this.emit(Connection.CLOSE);
   }
 
-  destroy(): void;
-  destroy(callback: Callback): void;
-  destroy(options: DestroyOptions): void;
-  destroy(options: DestroyOptions, callback: Callback): void;
-  destroy(options?: DestroyOptions | Callback, callback?: Callback): void {
+  onTimeout() {
+    if (this.closed) {
+      return;
+    }
+
+    this[kDelayedTimeoutId] = setTimeout(() => {
+      this[kStream].destroy();
+
+      this.closed = true;
+
+      const message = `connection ${this.id} to ${this.address} timed out`;
+      const beforeHandshake = this.hello == null;
+      for (const op of this[kQueue].values()) {
+        op.cb(new MongoNetworkTimeoutError(message, { beforeHandshake }));
+      }
+
+      this[kQueue].clear();
+      this.emit(Connection.CLOSE);
+    }, 1).unref(); // No need for this timer to hold the event loop open
+  }
+
+  onMessage(message: BinMsg | Response) {
+    const delayedTimeoutId = this[kDelayedTimeoutId];
+    if (delayedTimeoutId != null) {
+      clearTimeout(delayedTimeoutId);
+      this[kDelayedTimeoutId] = null;
+    }
+
+    // always emit the message, in case we are streaming
+    this.emit('message', message);
+    const operationDescription = this[kQueue].get(message.responseTo);
+    if (!operationDescription) {
+      return;
+    }
+
+    const callback = operationDescription.cb;
+
+    // SERVER-45775: For exhaust responses we should be able to use the same requestId to
+    // track response, however the server currently synthetically produces remote requests
+    // making the `responseTo` change on each response
+    this[kQueue].delete(message.responseTo);
+    if ('moreToCome' in message && message.moreToCome) {
+      // requeue the callback for next synthetic request
+      this[kQueue].set(message.requestId, operationDescription);
+    } else if (operationDescription.socketTimeoutOverride) {
+      this[kStream].setTimeout(this.socketTimeoutMS);
+    }
+
+    try {
+      // Pass in the entire description because it has BSON parsing options
+      message.parse(operationDescription);
+    } catch (err) {
+      // If this error is generated by our own code, it will already have the correct class applied
+      // if it is not, then it is coming from a catastrophic data parse failure or the BSON library
+      // in either case, it should not be wrapped
+      callback(err);
+      return;
+    }
+
+    if (message.documents[0]) {
+      const document: Document = message.documents[0];
+      const session = operationDescription.session;
+      if (session) {
+        updateSessionFromResponse(session, document);
+      }
+
+      if (document.$clusterTime) {
+        this[kClusterTime] = document.$clusterTime;
+        this.emit(Connection.CLUSTER_TIME_RECEIVED, document.$clusterTime);
+      }
+
+      if (operationDescription.command) {
+        if (document.writeConcernError) {
+          callback(new MongoWriteConcernError(document.writeConcernError, document));
+          return;
+        }
+
+        if (document.ok === 0 || document.$err || document.errmsg || document.code) {
+          callback(new MongoServerError(document));
+          return;
+        }
+      } else {
+        // Pre 3.2 support
+        if (document.ok === 0 || document.$err || document.errmsg) {
+          callback(new MongoServerError(document));
+          return;
+        }
+      }
+    }
+
+    callback(undefined, operationDescription.fullResult ? message : message.documents[0]);
+  }
+
+  destroy(options?: DestroyOptions, callback?: Callback): void {
     if (typeof options === 'function') {
       callback = options;
       options = { force: false };
@@ -379,7 +479,6 @@ export class Connection extends TypedEventEmitter<ConnectionEvents> {
     });
   }
 
-  /** @internal */
   command(
     ns: MongoDBNamespace,
     cmd: Document,
@@ -456,7 +555,6 @@ export class Connection extends TypedEventEmitter<ConnectionEvents> {
     }
   }
 
-  /** @internal */
   query(ns: MongoDBNamespace, cmd: Document, options: QueryOptions, callback: Callback): void {
     const isExplain = cmd.$explain != null;
     const readPreference = options.readPreference ?? ReadPreference.primary;
@@ -529,7 +627,6 @@ export class Connection extends TypedEventEmitter<ConnectionEvents> {
     );
   }
 
-  /** @internal */
   getMore(
     ns: MongoDBNamespace,
     cursorId: Long,
@@ -586,7 +683,6 @@ export class Connection extends TypedEventEmitter<ConnectionEvents> {
     this.command(ns, getMoreCmd, commandOptions, callback);
   }
 
-  /** @internal */
   killCursors(
     ns: MongoDBNamespace,
     cursorIds: Long[],
@@ -706,74 +802,6 @@ function supportsOpMsg(conn: Connection) {
   return maxWireVersion(conn) >= 6 && !description.__nodejs_mock_server__;
 }
 
-function messageHandler(conn: Connection) {
-  return function messageHandler(message: BinMsg | Response) {
-    // always emit the message, in case we are streaming
-    conn.emit('message', message);
-    const operationDescription = conn[kQueue].get(message.responseTo);
-    if (!operationDescription) {
-      return;
-    }
-
-    const callback = operationDescription.cb;
-
-    // SERVER-45775: For exhaust responses we should be able to use the same requestId to
-    // track response, however the server currently synthetically produces remote requests
-    // making the `responseTo` change on each response
-    conn[kQueue].delete(message.responseTo);
-    if ('moreToCome' in message && message.moreToCome) {
-      // requeue the callback for next synthetic request
-      conn[kQueue].set(message.requestId, operationDescription);
-    } else if (operationDescription.socketTimeoutOverride) {
-      conn[kStream].setTimeout(conn.socketTimeoutMS);
-    }
-
-    try {
-      // Pass in the entire description because it has BSON parsing options
-      message.parse(operationDescription);
-    } catch (err) {
-      // If this error is generated by our own code, it will already have the correct class applied
-      // if it is not, then it is coming from a catastrophic data parse failure or the BSON library
-      // in either case, it should not be wrapped
-      callback(err);
-      return;
-    }
-
-    if (message.documents[0]) {
-      const document: Document = message.documents[0];
-      const session = operationDescription.session;
-      if (session) {
-        updateSessionFromResponse(session, document);
-      }
-
-      if (document.$clusterTime) {
-        conn[kClusterTime] = document.$clusterTime;
-        conn.emit(Connection.CLUSTER_TIME_RECEIVED, document.$clusterTime);
-      }
-
-      if (operationDescription.command) {
-        if (document.writeConcernError) {
-          callback(new MongoWriteConcernError(document.writeConcernError, document));
-          return;
-        }
-
-        if (document.ok === 0 || document.$err || document.errmsg || document.code) {
-          callback(new MongoServerError(document));
-          return;
-        }
-      } else {
-        // Pre 3.2 support
-        if (document.ok === 0 || document.$err || document.errmsg) {
-          callback(new MongoServerError(document));
-          return;
-        }
-      }
-    }
-
-    callback(undefined, operationDescription.fullResult ? message : message.documents[0]);
-  };
-}
-
 function streamIdentifier(stream: Stream, options: ConnectionOptions): string {
   if (options.proxyHost) {
     // If proxy options are specified, the properties of `stream` itself

src/index.ts

@@ -186,12 +186,17 @@ export type {
   MongoCredentialsOptions
 } from './cmap/auth/mongo_credentials';
 export type {
+  BinMsg,
   GetMore,
   KillCursor,
+  MessageHeader,
   Msg,
   OpGetMoreOptions,
+  OpMsgOptions,
   OpQueryOptions,
+  OpResponseOptions,
   Query,
+  Response,
   WriteProtocolMessageType
 } from './cmap/commands';
 export type { LEGAL_TCP_SOCKET_OPTIONS, LEGAL_TLS_SOCKET_OPTIONS, Stream } from './cmap/connect';

test/tools/runner/hooks/configuration.js

@@ -66,15 +66,14 @@ async function initializeFilters(client) {
 }
 
 const testSkipBeforeEachHook = async function () {
-  // `metadata` always exists, `requires` is optional
-  const requires = this.currentTest.metadata.requires;
+  const metadata = this.currentTest.metadata;
 
-  if (requires && Object.keys(requires).length > 0) {
+  if (metadata && metadata.requires && Object.keys(metadata.requires).length > 0) {
     const failedFilter = filters.find(filter => !filter.filter(this.currentTest));
 
     if (failedFilter) {
       const filterName = failedFilter.constructor.name;
-      const metadataString = inspect(requires, {
+      const metadataString = inspect(metadata.requires, {
         colors: true,
         compact: true,
         depth: 10,