[FIX] web: BasicModel: fetch nested x2manys after onchange

When onchange RPCs return a command 4 (LINK TO), the res_id of the
record to link is given, and the BasicModel has to read the fields
in the view for that record. When one of those fields is an x2many
(for instance, displayed with widget many2many_tags), the
subrecords in the relation must be read as well (at least their
display_name).

Before this rev., this last part wasn't done by the BasicModel, and
as a consequence, the many2many_tags widget was always empty, even
though there were records in the relation.

Same thing applied to reference fields, but this is way more
uncommon.

This rev. ensures that x2manys and reference fields are correctly
fetched in this scenario.

1 files changed, 9 insertions, 2 deletions

diff --git a/addons/web/static/src/js/views/basic/basic_model.js b/addons/web/static/src/js/views/basic/basic_model.js
index 68fcd05fab1..ff4ed6d9147 100644
--- a/addons/web/static/src/js/views/basic/basic_model.js
+++ b/addons/web/static/src/js/views/basic/basic_model.js
@@ -1470,7 +1470,12 @@ var BasicModel = AbstractModel.extend({
                         list._changes = [{operation: 'REMOVE_ALL'}];
                     }
                 });
-                defs.push(self._readUngroupedList(list));
+                var def = self._readUngroupedList(list).then(function () {
+                    var x2ManysDef = self._fetchX2ManysBatched(list);
+                    var referencesDef = self._fetchReferencesBatched(list);
+                    return $.when(x2ManysDef, referencesDef);
+                });
+                defs.push(def);
             } else {
                 var newValue = self._parseServerValue(field, val);
                 if (newValue !== oldValue) {
@@ -1975,7 +1980,9 @@ var BasicModel = AbstractModel.extend({
         _.each(list.data, function (dataPoint) {
             var record = self.localData[dataPoint];
             var value = record.data[fieldName];
-            if (value) {
+            // if the reference field has already been fetched, the value is a
+            // datapoint ID, and in this case there's nothing to do
+            if (value && !self.localData[value]) {
                 var model = value.split(',')[0];
                 var resID = value.split(',')[1];
                 if (!(model in toFetch)) {