From 3529c7d47f483ca2f6f8de9ba3049e97b0bada13 Mon Sep 17 00:00:00 2001
From: Isabel Atkinson <isabel.atkinson@mongodb.com>
Date: Fri, 5 Dec 2025 11:48:33 -0700
Subject: [PATCH 1/2] add nModified default

---
 driver/src/operation/bulk_write.rs | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/driver/src/operation/bulk_write.rs b/driver/src/operation/bulk_write.rs
index 60f78b77a..ccdadfab6 100644
--- a/driver/src/operation/bulk_write.rs
+++ b/driver/src/operation/bulk_write.rs
@@ -183,12 +183,8 @@ where
                         result.add_insert_result(index, insert_result);
                     }
                     OperationType::Update => {
-                        let modified_count =
-                            n_modified.ok_or_else(|| ErrorKind::InvalidResponse {
-                                message: "nModified value not returned for update bulkWrite \
-                                          operation"
-                                    .into(),
-                            })?;
+                        // default to 0 as a workaround for SERVER-113026
+                        let modified_count = n_modified.unwrap_or(0);
                         let update_result = UpdateResult {
                             matched_count: n,
                             modified_count,

From 3a1f514b50de06c6ed6d8ffc2451cd0c7f76ae67 Mon Sep 17 00:00:00 2001
From: Isabel Atkinson <isabel.atkinson@mongodb.com>
Date: Fri, 5 Dec 2025 11:55:08 -0700
Subject: [PATCH 2/2] optimization

---
 driver/src/operation/bulk_write.rs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/driver/src/operation/bulk_write.rs b/driver/src/operation/bulk_write.rs
index ccdadfab6..d4e5539b9 100644
--- a/driver/src/operation/bulk_write.rs
+++ b/driver/src/operation/bulk_write.rs
@@ -175,6 +175,12 @@ where
                 n_modified,
                 upserted,
             } => {
+                // small optimization for SERVER-113344: if the server unexpectedly returns a
+                // success response for an errors-only bulk write, skip deserializing the individual
+                // response, as the call to add_*_result will be a no-op
+                if R::errors_only() {
+                    return Ok(());
+                }
                 let model = self.get_model(response.index)?;
                 match model.operation_type() {
                     OperationType::Insert => {