refactor(NODE-3519): remove force unpinning and simplify findOne (#2929)

Author: durran

src/collection.ts

@@ -1,4 +1,4 @@
-import { DEFAULT_PK_FACTORY, emitWarningOnce, resolveOptions } from './utils';
+import { DEFAULT_PK_FACTORY, emitWarningOnce, maybePromise, resolveOptions } from './utils';
 import { ReadPreference, ReadPreferenceLike } from './read_preference';
 import {
   normalizeHintField,
@@ -40,7 +40,6 @@ import {
   EstimatedDocumentCountOptions
 } from './operations/estimated_document_count';
 import type { FindOptions } from './operations/find';
-import { FindOneOperation } from './operations/find_one';
 import {
   FindOneAndDeleteOperation,
   FindOneAndReplaceOperation,
@@ -709,16 +708,13 @@ export class Collection<TSchema extends Document = Document> {
       (callback = filter as Callback<Document | undefined>), (filter = {}), (options = {});
     if (typeof options === 'function') (callback = options), (options = {});
 
-    filter ??= {};
-
-    return executeOperation(
-      getTopology(this),
-      new FindOneOperation(
-        this as TODO_NODE_3286,
-        filter,
-        resolveOptions(this, options)
-      ) as TODO_NODE_3286,
-      callback as TODO_NODE_3286
+    const finalFilter = filter ?? {};
+    const finalOptions = options ?? {};
+    return maybePromise(callback, callback =>
+      this.find(finalFilter, finalOptions)
+        .limit(-1)
+        .batchSize(1)
+        .next((error, result) => callback(error, result ?? undefined))
     );
   }
 

src/cursor/abstract_cursor.ts

@@ -769,7 +769,7 @@ function cleanupCursor(
       }
 
       if (!session.inTransaction()) {
-        maybeClearPinnedConnection(session, { error, force: true });
+        maybeClearPinnedConnection(session, { error });
       }
     }
 
@@ -786,7 +786,7 @@ function cleanupCursor(
       }
 
       if (!session.inTransaction()) {
-        maybeClearPinnedConnection(session, { error, force: true });
+        maybeClearPinnedConnection(session, { error });
       }
     }