From 8cfd8ff2f484270c578d5c466bf9a568a8197e5f Mon Sep 17 00:00:00 2001
From: Rahul Lanjewar <rahullanjewar93@gmail.com>
Date: Sun, 9 Nov 2025 02:07:59 +0530
Subject: [PATCH 1/3] feat: add information about, db collection and index name

---
 spec/schemas.spec.js                          |  1 +
 .../Storage/Mongo/MongoStorageAdapter.js      | 27 +++++++++++++++++--
 2 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/spec/schemas.spec.js b/spec/schemas.spec.js
index 7891fa847e..6acadbb948 100644
--- a/spec/schemas.spec.js
+++ b/spec/schemas.spec.js
@@ -3835,6 +3835,7 @@ describe('schemas', () => {
         .then(done.fail)
         .catch(error => {
           expect(error.code).toEqual(Parse.Error.DUPLICATE_VALUE);
+          expect(error.message).toEqual('A duplicate value for a field with unique values was provided Duplicate index: code_1 on collection test_UniqueIndexClass in db parseServerMongoAdapterTestDatabase')
           done();
         });
     });
diff --git a/src/Adapters/Storage/Mongo/MongoStorageAdapter.js b/src/Adapters/Storage/Mongo/MongoStorageAdapter.js
index 481d5257d9..f8f133488a 100644
--- a/src/Adapters/Storage/Mongo/MongoStorageAdapter.js
+++ b/src/Adapters/Storage/Mongo/MongoStorageAdapter.js
@@ -26,6 +26,29 @@ const ReadPreference = mongodb.ReadPreference;
 
 const MongoSchemaCollectionName = '_SCHEMA';
 
+
+// If we get a unique index error from mongo, try to parse it. If successful, return it.
+const mongoUniqueIndexErrorFormatter = (message) => {
+  /**
+   * Sample error message that we are getting from mongo
+   * 'Plan executor error during findAndModify :: caused by :: E11000 duplicate key error collection: parseServerMongoAdapterTestDatabase.test_UniqueIndexClass index: code_1 dup key: { code: 2 }'
+   */
+  const regex = /collection:\s*([\w]+)\.([\w]+)\s+index:\s*([\w_]+)/;
+
+  const match = message.match(regex);
+
+  if (match) {
+    const dbName = match[1];
+    const collectionName = match[2];
+    const indexName = match[3];
+    // Adding extra starting space to make it more readable.
+    return ` Duplicate index: ${indexName} on collection ${collectionName} in db ${dbName}`;
+  }
+
+  // Return nothing
+  return '';
+}
+
 const storageAdapterAllCollections = mongoAdapter => {
   return mongoAdapter
     .connect()
@@ -490,7 +513,7 @@ export class MongoStorageAdapter implements StorageAdapter {
           // Duplicate value
           const err = new Parse.Error(
             Parse.Error.DUPLICATE_VALUE,
-            'A duplicate value for a field with unique values was provided'
+            `A duplicate value for a field with unique values was provided.${mongoUniqueIndexErrorFormatter(error.message)}`
           );
           err.underlyingError = error;
           if (error.message) {
@@ -575,7 +598,7 @@ export class MongoStorageAdapter implements StorageAdapter {
         if (error.code === 11000) {
           throw new Parse.Error(
             Parse.Error.DUPLICATE_VALUE,
-            'A duplicate value for a field with unique values was provided'
+            `A duplicate value for a field with unique values was provided.${mongoUniqueIndexErrorFormatter(error.message)}`
           );
         }
         throw error;

From 17c89093570b80e5dd5f5a8643fbc25235957aeb Mon Sep 17 00:00:00 2001
From: Rahul Lanjewar <rahullanjewar93@gmail.com>
Date: Sun, 9 Nov 2025 02:12:39 +0530
Subject: [PATCH 2/3] fix: minor

---
 spec/schemas.spec.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/spec/schemas.spec.js b/spec/schemas.spec.js
index 6acadbb948..618a8c547a 100644
--- a/spec/schemas.spec.js
+++ b/spec/schemas.spec.js
@@ -3835,7 +3835,7 @@ describe('schemas', () => {
         .then(done.fail)
         .catch(error => {
           expect(error.code).toEqual(Parse.Error.DUPLICATE_VALUE);
-          expect(error.message).toEqual('A duplicate value for a field with unique values was provided Duplicate index: code_1 on collection test_UniqueIndexClass in db parseServerMongoAdapterTestDatabase')
+          expect(error.message).toEqual('A duplicate value for a field with unique values was provided. Duplicate index: code_1 on collection test_UniqueIndexClass in db parseServerMongoAdapterTestDatabase')
           done();
         });
     });

From 0473c9046eb82675ae5c5fe7b4e0855fe4c78ae8 Mon Sep 17 00:00:00 2001
From: Rahul Lanjewar <63550998+RahulLanjewar93@users.noreply.github.com>
Date: Sun, 9 Nov 2025 02:22:24 +0530
Subject: [PATCH 3/3] Apply suggestion from @RahulLanjewar93

Signed-off-by: Rahul Lanjewar <63550998+RahulLanjewar93@users.noreply.github.com>
---
 src/Adapters/Storage/Mongo/MongoStorageAdapter.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Adapters/Storage/Mongo/MongoStorageAdapter.js b/src/Adapters/Storage/Mongo/MongoStorageAdapter.js
index f8f133488a..8f674c21a2 100644
--- a/src/Adapters/Storage/Mongo/MongoStorageAdapter.js
+++ b/src/Adapters/Storage/Mongo/MongoStorageAdapter.js
@@ -33,7 +33,7 @@ const mongoUniqueIndexErrorFormatter = (message) => {
    * Sample error message that we are getting from mongo
    * 'Plan executor error during findAndModify :: caused by :: E11000 duplicate key error collection: parseServerMongoAdapterTestDatabase.test_UniqueIndexClass index: code_1 dup key: { code: 2 }'
    */
-  const regex = /collection:\s*([\w]+)\.([\w]+)\s+index:\s*([\w_]+)/;
+  const regex = /collection:\s*([\w-]+)\.([\w-]+)\s+index:\s*([\w-]+)/;
 
   const match = message.match(regex);