test: remove read preference pre 5.0

src/cmap/connection.ts

@@ -97,6 +97,7 @@ export interface CommandOptions extends BSONSerializeOptions {
   session?: ClientSession;
   documentsReturnedIn?: string;
   noResponse?: boolean;
+  omitReadPreference?: boolean;
 
   // FIXME: NODE-2802
   willRetryWrite?: boolean;

src/operations/command.ts

@@ -10,6 +10,7 @@ import type { Server } from '../sdam/server';
 import type { BSONSerializeOptions, Document } from '../bson';
 import type { ReadConcernLike } from './../read_concern';
 import { Explain, ExplainOptions } from '../explain';
+import { MIN_SECONDARY_WRITE_WIRE_VERSION } from '../sdam/server_selection';
 
 const SUPPORTS_WRITE_CONCERN_AND_COLLATION = 5;
 
@@ -126,6 +127,12 @@ export abstract class CommandOperation<T> extends AbstractOperation<T> {
       Object.assign(cmd, { readConcern: this.readConcern });
     }
 
+    if (this.trySecondaryWrite && serverWireVersion < MIN_SECONDARY_WRITE_WIRE_VERSION) {
+      /* eslint no-console: 0 */
+      console.log('need to remove read preference from options');
+      options.omitReadPreference = true;
+    }
+
     if (options.collation && serverWireVersion < SUPPORTS_WRITE_CONCERN_AND_COLLATION) {
       callback(
         new MongoCompatibilityError(

src/operations/operation.ts

@@ -31,6 +31,7 @@ export interface OperationOptions extends BSONSerializeOptions {
 
   /** @internal Hints to `executeOperation` that this operation should not unpin on an ended transaction */
   bypassPinningCheck?: boolean;
+  omitReadPreference?: boolean;
 }
 
 /** @internal */
@@ -49,7 +50,7 @@ export abstract class AbstractOperation<TResult = any> {
   readPreference: ReadPreference;
   server!: Server;
   bypassPinningCheck: boolean;
-  trySecondaryWrite = false;
+  trySecondaryWrite: boolean;
 
   // BSON serialization options
   bsonOptions?: BSONSerializeOptions;
@@ -73,6 +74,7 @@ export abstract class AbstractOperation<TResult = any> {
 
     this.options = options;
     this.bypassPinningCheck = !!options.bypassPinningCheck;
+    this.trySecondaryWrite = false;
   }
 
   abstract execute(server: Server, session: ClientSession, callback: Callback<TResult>): void;

src/sdam/server.ts

@@ -299,6 +299,14 @@ export class Server extends TypedEventEmitter<ServerEvents> {
     // Clone the options
     const finalOptions = Object.assign({}, options, { wireProtocolCommand: false });
 
+    // There are cases where we need to flag the read preference not to get sent in
+    // the command, such as pre-5.0 servers attempting to perform an aggregate write
+    // with a non-primary read preference. In this case the effective read preference
+    // (primary) is not the same as the provided and must be removed completely.
+    if (finalOptions.omitReadPreference) {
+      delete finalOptions.readPreference;
+    }
+
     // error if collation not supported
     if (collationNotSupported(this, cmd)) {
       callback(new MongoCompatibilityError(`Server ${this.name} does not support collation`));

src/sdam/server_selection.ts

@@ -46,6 +46,8 @@ export function secondaryWritableServerSelector(
   /* eslint no-console: 0 */
   console.log('select', readPreference, wireVersion);
   if (!readPreference || (wireVersion && wireVersion < MIN_SECONDARY_WRITE_WIRE_VERSION)) {
+    /* eslint no-console: 0 */
+    console.log('force select primary');
     return readPreferenceServerSelector(ReadPreference.primary);
   }
   return readPreferenceServerSelector(readPreference);

test/functional/crud_spec.test.js

@@ -424,7 +424,8 @@ describe('CRUD spec v1', function () {
   }
 });
 
-describe('CRUD unified', function () {
+// https://jira.mongodb.org/browse/NODE-3655
+describe.only('CRUD unified', function () {
   for (const crudSpecTest of loadSpecTests('crud/unified')) {
     expect(crudSpecTest).to.exist;
     const testDescription = String(crudSpecTest.description);