fix: Cosmos DB: E11000 duplicate key error

I’ve updated this PR to remove unique: true and sparse: true from the optional social login fields (googleId, facebookId, etc.) and switch them to simple indexes (index: true). This resolves the Cosmos DB “duplicate key” errors caused by multiple null values and ensures compatibility with both Cosmos DB and MongoDB. The email field remains required and unique, preserving overall identity uniqueness.

api/models/schema/userSchema.js

@@ -84,38 +84,31 @@ const userSchema = mongoose.Schema(
     },
     googleId: {
       type: String,
-      unique: true,
-      sparse: true,
+      index: true,
     },
     facebookId: {
       type: String,
-      unique: true,
-      sparse: true,
+      index: true,
     },
     openidId: {
       type: String,
-      unique: true,
-      sparse: true,
+      index: true,
     },
     ldapId: {
       type: String,
-      unique: true,
-      sparse: true,
+      index: true,
     },
     githubId: {
       type: String,
-      unique: true,
-      sparse: true,
+      index: true,
     },
     discordId: {
       type: String,
-      unique: true,
-      sparse: true,
+      index: true,
     },
     appleId: {
       type: String,
-      unique: true,
-      sparse: true,
+      index: true,
     },
     plugins: {
       type: Array,

api/strategies/socialLogin.js

@@ -3,6 +3,11 @@ const { isEnabled } = require('~/server/utils');
 const { findUser } = require('~/models');
 const { logger } = require('~/config');
 
+/**
+ * Returns a function that handles the social login flow for a given provider.
+ * @param {string} provider - The provider name (e.g. 'google', 'facebook').
+ * @param {Function} getProfileDetails - A function to extract user details from the provider profile.
+ */
 const socialLogin =
   (provider, getProfileDetails) => async (accessToken, refreshToken, idToken, profile, cb) => {
     try {
@@ -31,6 +36,8 @@ const socialLogin =
         });
         return cb(null, newUser);
       }
+
+      return cb(null, null);
     } catch (err) {
       logger.error(`[${provider}Login]`, err);
       return cb(err);