From 0b0ea7540261c62bd7a8bea12eda11b3363f7318 Mon Sep 17 00:00:00 2001
From: Adrien Lepoutre <adrien.lepoutre@adfab.com>
Date: Mon, 2 Apr 2018 17:50:03 -0400
Subject: [PATCH] ISSUE 825 - Losing OneToOne relation in the content manager -
 Fixes #825

---
 .../config/queries/mongoose.js                | 40 +++++++++++++------
 1 file changed, 27 insertions(+), 13 deletions(-)

diff --git a/packages/strapi-plugin-content-manager/config/queries/mongoose.js b/packages/strapi-plugin-content-manager/config/queries/mongoose.js
index c346228ad2..9a173a8e7c 100755
--- a/packages/strapi-plugin-content-manager/config/queries/mongoose.js
+++ b/packages/strapi-plugin-content-manager/config/queries/mongoose.js
@@ -85,11 +85,11 @@ module.exports = {
               }
 
               // Remove previous relationship asynchronously if it exists.
-              virtualFields.push(
+              let promise = new Promise(resolve => {
                 strapi.query(details.model || details.collection, details.plugin).findOne({ id : recordId })
                   .then(record => {
                     if (record && _.isObject(record[details.via])) {
-                      return module.exports.update.call(this, {
+                      module.exports.update.call(this, {
                         id: record[details.via][this.primaryKey] || record[details.via].id,
                         values: {
                           [current]: null
@@ -97,20 +97,34 @@ module.exports = {
                         parseRelationships: false
                       });
                     }
-
-                    return Promise.resolve();
+                    resolve()
                   })
-              );
+              })
+              virtualFields.push(promise);
 
-              // Update the record on the other side.
+              // Updating the new relations
               // When params.values[current] is null this means that we are removing the relation.
-              virtualFields.push(strapi.query(details.model || details.collection, details.plugin).update({
-                id: recordId,
-                values: {
-                  [details.via]: _.isNull(params.values[current]) ? null : value[this.primaryKey] || value.id || value._id
-                },
-                parseRelationships: false
-              }));
+              promise.then(response => {
+                // Recreate relation on the first side
+                virtualFields.push(strapi.query(details.model || details.collection, details.plugin).update({
+                  id: recordId,
+                  values: {
+                    [details.via]: _.isNull(params.values[current]) ? null : value[this.primaryKey] || value.id || value._id
+                  },
+                  parseRelationships: false
+                }));
+
+                // Recreate relation on the other side if the value is not null
+                if (!_.isNull(params.values[current])) {
+                  module.exports.update.call(this, {
+                    id: value[this.primaryKey] || value.id || value._id,
+                    values: {
+                      [current]: recordId
+                    },
+                    parseRelationships: false
+                  });
+                }
+              });
 
               acc[current] = _.isNull(params.values[current]) ? null : value[current];
             }