DRIVERS-3036 Remove the BSON document size validation requirement for the client bulk write operation (#1725)

Author: stIncMale

source/crud/bulk-write.md

@@ -634,22 +634,6 @@ write concern containing the following message:
 
 > Cannot request unacknowledged write concern and ordered writes
 
-### Size Limits
-
-The server reports a `maxBsonObjectSize` in its `hello` response. This value defines the maximum size for documents that
-are inserted into the database. Documents that are sent to the server but are not intended to be inserted into the
-database (e.g. command documents) have a size limit of `maxBsonObjectSize + 16KiB`. When an acknowledged write concern
-is used, drivers MUST NOT perform any checks related to these size limits and MUST rely on the server to raise an error
-if a limit is exceeded. However, when an unacknowledged write concern is used, drivers MUST raise an error if one of the
-following limits is exceeded:
-
-- The size of a document to be inserted MUST NOT exceed `maxBsonObjectSize`. This applies to the `document` field of an
-    `InsertOneModel` and the `replacement` field of a `ReplaceOneModel`.
-- The size of an entry in the `ops` array MUST NOT exceed `maxBsonObjectSize + 16KiB`.
-- The size of the `bulkWrite` command document MUST NOT exceed `maxBsonObjectSize + 16KiB`.
-
-See [SERVER-10643](https://jira.mongodb.org/browse/SERVER-10643) for more details on these size limits.
-
 ## Auto-Encryption
 
 If `MongoClient.bulkWrite` is called on a `MongoClient` configured with `AutoEncryptionOpts`, drivers MUST return an
@@ -922,8 +906,19 @@ number was determined by constructing `OP_MSG` messages with various fields atta
 Drivers are required to use this value even if they are capable of determining the exact size of the message prior to
 batch-splitting to standardize implementations across drivers and simplify batch-splitting testing.
 
+### Why is there no requirement to validate the size of a BSON document?
+
+Following
+["_Where possible, depend on server to return errors_"](https://github.com/mongodb/specifications/blob/f8dbd2469f18d093f917efa1f758024bca5d3aaa/source/driver-mantras.md#where-possible-depend-on-server-to-return-errors),
+drivers should rely on the server to return errors about exceeded size limits. Such reliance is not possible for
+unacknowledged writes. This specification previously required drivers to check size limits for unacknowledged writes.
+The requirement has since been removed. Checking size limits complicates some driver implementations. Returning a driver
+error in this specific situation does not seem helpful enough to require size checks.
+
 ## **Changelog**
 
+- 2024-11-05: Updated the requirements regarding the size validation.
+
 - 2024-10-07: Error if `w:0` is used with `ordered=true` or `verboseResults=true`.
 
 - 2024-10-01: Add sort option to `replaceOne` and `updateOne`.

source/crud/tests/README.md

@@ -370,56 +370,15 @@ Assert that a CommandStartedEvent was observed for the `killCursors` command.
 
 ### 10. `MongoClient.bulkWrite` returns error for unacknowledged too-large insert
 
-This test must only be run on 8.0+ servers. This test must be skipped on Atlas Serverless.
-
-Construct a `MongoClient` (referred to as `client`).
-
-Perform a `hello` command using `client` and record the following values from the response: `maxBsonObjectSize`.
-
-Then, construct the following document (referred to as `document`):
-
-```javascript
-{
-  "a": "b".repeat(maxBsonObjectSize)
-}
-```
+Removed.
 
 #### With insert
 
-Construct the following write model (referred to as `model`):
-
-```javascript
-InsertOne: {
-  "namespace": "db.coll",
-  "document": document
-}
-```
-
-Construct as list of write models (referred to as `models`) with the one `model`.
-
-Call `MongoClient.bulkWrite` with `models`. Pass `BulkWriteOptions` with `ordered` set to `false` and `writeConcern` set
-to an unacknowledged write concern.
-
-Expect a client-side error due the size.
+Removed.
 
 #### With replace
 
-Construct the following write model (referred to as `model`):
-
-```javascript
-ReplaceOne: {
-  "namespace": "db.coll",
-  "filter": {},
-  "replacement": document
-}
-```
-
-Construct as list of write models (referred to as `models`) with the one `model`.
-
-Call `MongoClient.bulkWrite` with `models`. Pass `BulkWriteOptions` with `ordered` set to `false` and `writeConcern` set
-to an unacknowledged write concern.
-
-Expect a client-side error due the size.
+Removed.
 
 ### 11. `MongoClient.bulkWrite` batch splits when the addition of a new namespace exceeds the maximum message size