fix sasl prep issue

src/cmap/auth/scram.ts

@@ -2,7 +2,7 @@ import * as crypto from 'crypto';
 import { promisify } from 'util';
 
 import { Binary, type Document } from '../../bson';
-import { saslprep } from '../../deps';
+import * as deps from '../../deps';
 import {
   MongoInvalidArgumentError,
   MongoMissingCredentialsError,
@@ -34,7 +34,10 @@ class ScramSHA extends AuthProvider {
     if (!credentials) {
       throw new MongoMissingCredentialsError('AuthContext must provide credentials.');
     }
-    if (cryptoMethod === 'sha256' && saslprep == null) {
+    if (
+      cryptoMethod === 'sha256' &&
+      (!('kModuleError' in deps.saslprep) || typeof deps.saslprep !== 'function')
+    ) {
       emitWarning('Warning: no saslprep library specified. Passwords will not be sanitized');
     }
 
@@ -140,7 +143,10 @@ async function continueScramConversation(
 
   let processedPassword;
   if (cryptoMethod === 'sha256') {
-    processedPassword = 'kModuleError' in saslprep ? password : saslprep(password);
+    processedPassword =
+      'kModuleError' in deps.saslprep || typeof deps.saslprep !== 'function'
+        ? password
+        : deps.saslprep(password);
   } else {
     processedPassword = passwordDigest(username, password);
   }

test/integration/auth/scram_sha_256.test.ts

@@ -0,0 +1,41 @@
+import { expect } from 'chai';
+import * as sinon from 'sinon';
+
+import { deps, type MongoClient } from '../../mongodb';
+
+describe('SCRAM_SHA_256', function () {
+  context('when saslprep is not a function', () => {
+    let client: MongoClient;
+    beforeEach(function () {
+      if (!this.configuration.parameters.authenticationMechanisms.includes('SCRAM-SHA-256')) {
+        this.currentTest!.skipReason = 'Test requires that SCRAM-SHA-256 be enabled on the server.';
+        this.currentTest!.skip();
+      }
+    });
+
+    beforeEach('setup mocks', function () {
+      sinon.stub(deps, 'saslprep').value({});
+      client = this.configuration.newClient({ authMechanism: 'SCRAM-SHA-256' });
+    });
+
+    afterEach(() => {
+      sinon.restore();
+      return client.close();
+    });
+
+    it('does not throw an error', { requires: { auth: 'enabled' } }, async function () {
+      await client.connect();
+    });
+
+    it('emits a warning', { requires: { auth: 'enabled' } }, async function () {
+      const warnings: Array<Error> = [];
+      process.once('warning', w => warnings.push(w));
+      await client.connect();
+      expect(warnings).to.have.lengthOf(1);
+      expect(warnings[0]).to.have.property(
+        'message',
+        'Warning: no saslprep library specified. Passwords will not be sanitized'
+      );
+    });
+  });
+});

test/mongodb.ts

@@ -143,6 +143,7 @@ export * from '../src/cursor/list_indexes_cursor';
 export * from '../src/cursor/run_command_cursor';
 export * from '../src/db';
 export * from '../src/deps';
+export * as deps from '../src/deps';
 export * from '../src/encrypter';
 export * from '../src/error';
 export * from '../src/explain';