fix(mongodb-runner): don't leave a dangling --port flag on secondaries

packages/mongodb-runner/src/mongocluster.spec.ts

@@ -173,6 +173,34 @@ describe('MongoCluster', function () {
     expect(+hello.passives.length + +hello.hosts.length).to.equal(3);
   });
 
+  it('can spawn a 8.x replset with a pre-specified port for the primary', async function () {
+    cluster = await MongoCluster.start({
+      version: '8.x',
+      topology: 'replset',
+      tmpDir,
+      args: ['--port', '50080'],
+    });
+    expect(cluster.connectionString).to.include(`:50080`);
+    const hello = await cluster.withClient(async (client) => {
+      return await client.db('admin').command({ hello: 1 });
+    });
+    expect(+hello.passives.length + +hello.hosts.length).to.equal(3);
+  });
+
+  it('can spawn a 8.x replset with a pre-specified --port= for the primary', async function () {
+    cluster = await MongoCluster.start({
+      version: '8.x',
+      topology: 'replset',
+      tmpDir,
+      args: ['--port=50081'],
+    });
+    expect(cluster.connectionString).to.include(`:50081`);
+    const hello = await cluster.withClient(async (client) => {
+      return await client.db('admin').command({ hello: 1 });
+    });
+    expect(+hello.passives.length + +hello.hosts.length).to.equal(3);
+  });
+
   it('can spawn a 8.x replset with specific number of arbiters and secondaries', async function () {
     cluster = await MongoCluster.start({
       version: '8.x',
@@ -699,6 +727,28 @@ describe('MongoCluster', function () {
     });
   });
 
+  it('can spawn a sharded cluster with a pre-specified port for mongos (--port x)', async function () {
+    cluster = await MongoCluster.start({
+      version: '8.x',
+      topology: 'sharded',
+      tmpDir,
+      secondaries: 0,
+      mongosArgs: [['--port', '50082']],
+    });
+    expect(cluster.connectionString).to.include(`:50082`);
+  });
+
+  it('can spawn a sharded cluster with a pre-specified port for mongos (--port=x)', async function () {
+    cluster = await MongoCluster.start({
+      version: '8.x',
+      topology: 'sharded',
+      tmpDir,
+      secondaries: 0,
+      mongosArgs: [['--port=50083']],
+    });
+    expect(cluster.connectionString).to.include(`:50083`);
+  });
+
   it('can add authentication options and verify them after serialization', async function () {
     cluster = await MongoCluster.start({
       version: '8.x',

packages/mongodb-runner/src/mongocluster.ts

@@ -19,6 +19,7 @@ import {
   debugVerbose,
   makeConnectionString,
   safePromiseAll,
+  hasPortArg,
 } from './util';
 import { OIDCMockProviderProcess } from './oidc';
 import { EventEmitter } from 'events';
@@ -166,7 +167,7 @@ export type MongoClusterEvents = {
 function removePortArg([...args]: string[]): string[] {
   let portArgIndex = -1;
   if ((portArgIndex = args.indexOf('--port')) !== -1) {
-    args.splice(portArgIndex + 1, 1);
+    args.splice(portArgIndex, 2);
   } else if (
     (portArgIndex = args.findIndex((arg) => arg.startsWith('--port='))) !== -1
   ) {
@@ -175,13 +176,6 @@ function removePortArg([...args]: string[]): string[] {
   return args;
 }
 
-function hasPortArg(args: string[] | undefined): boolean {
-  if (!args) return false;
-  return (
-    args.includes('--port') || args.some((arg) => arg.startsWith('--port='))
-  );
-}
-
 function processRSMembers(options: MongoClusterOptions): {
   rsMembers: RSMemberOptions[];
   replSetName: string;

packages/mongodb-runner/src/mongoserver.ts

@@ -22,6 +22,7 @@ import {
   makeConnectionString,
   sleep,
   eventually,
+  hasPortArg,
 } from './util';
 
 /**
@@ -187,7 +188,7 @@ export class MongoServer extends EventEmitter<MongoServerEvents> {
   }
 
   static async start({ ...options }: MongoServerOptions): Promise<MongoServer> {
-    if (options.binary === 'mongos' && !options.args?.includes('--port')) {
+    if (options.binary === 'mongos' && !hasPortArg(options.args)) {
       // SERVER-78384: mongos before 7.1.0 does not understand `--port 0` ...
       // Just pick a random port in [1024, 49152), try to listen, and continue until
       // we find a free one.
@@ -265,7 +266,7 @@ export class MongoServer extends EventEmitter<MongoServerEvents> {
     }
 
     commandline.push(...(options.args ?? []));
-    if (!options.args?.includes('--port')) commandline.push('--port', '0');
+    if (!hasPortArg(options.args)) commandline.push('--port', '0');
     if (!options.args?.includes('--dbpath') && options.binary === 'mongod')
       commandline.push('--dbpath', options.docker ? '/tmp' : srv.dbPath!);
     if (

packages/mongodb-runner/src/util.ts

@@ -10,6 +10,11 @@ export const sleep = (ms: number): Promise<void> =>
   new Promise((r) => setTimeout(r, ms));
 export const range = (n: number): number[] => [...Array(n).keys()];
 
+export function hasPortArg(args: string[] | undefined): boolean {
+  if (!args) return false;
+  return args.some((arg) => arg === '--port' || arg.startsWith('--port='));
+}
+
 /**
  * This function iterates `iterable` and applies `fn` to each item that
  * `iterable` produces.  `fn` is not awaited on each iteration of `iterable`.