fix(*): run autoupdate in serial to avoid conflicts

Signed-off-by: Simon Stone <[email protected]>

Author: Simon Stone

lib/mongodb.js

@@ -1870,7 +1870,8 @@ MongoDB.prototype.autoupdate = function(models, cb) {
 
     const enableGeoIndexing = this.settings.enableGeoIndexing === true;
 
-    async.each(
+    // Make it serial as multiple models might map to the same collection
+    async.eachSeries(
       models,
       function(modelName, modelCallback) {
         const indexes = self._models[modelName].settings.indexes || [];
@@ -1954,7 +1955,8 @@ MongoDB.prototype.autoupdate = function(models, cb) {
           debug('create indexes: ', indexList);
         }
 
-        async.each(
+        // Make it serial as multiple indexes may try to create the same collection at once
+        async.eachSeries(
           indexList,
           function(index, indexCallback) {
             if (self.debug) {