DRIVERS-2658 Add hint support for distinct. (#1715)

Author: matthewdale

source/crud/crud.md

@@ -427,6 +427,16 @@ class DistinctOptions {
    * and providing one will result in a server-side error.
    */
   comment: Optional<any>;
+
+  /**
+   * The index to use. Specify either the index name as a string or the index key pattern.
+   * If specified, then the query system will only consider plans using the hinted index.
+   *
+   * This option is sent only if the caller explicitly provides a value. The default is to not send a value.
+   *
+   * @see https://www.mongodb.com/docs/manual/reference/command/find/
+   */
+  hint: Optional<(String | Document)>;
 }
 
 enum CursorType {
@@ -2488,6 +2498,8 @@ aforementioned allowance in the SemVer spec.
 
 - 2024-11-04: Always send a value for `bypassDocumentValidation` if it was specified.
 
+- 2024-11-01: Add hint to DistinctOptions
+
 - 2024-10-30: Document query limitations in `countDocuments`.
 
 - 2024-10-28: Clarified that generated identifiers should be prepended to documents.

source/crud/tests/unified/distinct-hint.json

@@ -0,0 +1,73 @@
+description: "distinct-hint"
+
+schemaVersion: "1.0"
+runOnRequirements:
+  # https://jira.mongodb.org/browse/SERVER-14227
+  # Server supports distinct with hint starting from 7.1.0.
+  - minServerVersion: "7.1.0"
+
+createEntities:
+  - client:
+      id: &client0 client0
+      observeEvents: [ commandStartedEvent ]
+  - database:
+      id: &database0 database0
+      client: *client0
+      databaseName: &database0Name distinct-hint-tests
+  - collection:
+      id: &collection0 collection0
+      database: *database0
+      collectionName: &collection0Name coll0
+
+initialData:
+  - collectionName: *collection0Name
+    databaseName: *database0Name
+    documents:
+      - { _id: 1, x: 11 }
+      - { _id: 2, x: 22 }
+      - { _id: 3, x: 33 }
+
+tests:
+  - description: "distinct with hint string"
+    operations:
+      - name: distinct
+        object: *collection0
+        arguments:
+          fieldName: &fieldName x
+          filter: &filter { _id: 1 }
+          hint: _id_
+        expectResult: [ 11 ]
+    expectEvents:
+      - client: *client0
+        events:
+          - commandStartedEvent:
+              command:
+                distinct: *collection0Name
+                key: *fieldName
+                query: *filter
+                hint: _id_
+              commandName: distinct
+              databaseName: *database0Name
+
+  - description: "distinct with hint document"
+    operations:
+      - name: distinct
+        object: *collection0
+        arguments:
+          fieldName: *fieldName
+          filter: *filter
+          hint:
+            _id: 1
+        expectResult: [ 11 ]
+    expectEvents:
+      - client: *client0
+        events:
+          - commandStartedEvent:
+              command:
+                distinct: *collection0Name
+                key: *fieldName
+                query: *filter
+                hint:
+                  _id: 1
+              commandName: distinct
+              databaseName: *database0Name