[FIX] web: better experience for one2many edition (paged)

A big problem with the o2m edition happens when the user has a full page
(so, in general, 40 records) and click on add.

If the o2m is in editable="bottom" mode (which is actually a really
common usecase), then the next record will be added at the end.
However, since we have a limit of 40, it will immediately go to the next
page.

The effect is even weirder when there is a required field in the tree
view.  In that case, the new record appears correctly, the user can edit
it, then, as soon as the required fields are set, it will immediately
disappear from the current screen.

In this commit, we have a really simple solution: we simply increase the
limit in this case.  An interesting thing is that it is actually temporary:
when the user goes to the next page, the limit is back to its original
value (due to the pager click: it resets the value to what the pager knows).

1 files changed, 7 insertions, 1 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 c8bd4ae030f..f081d0a6caa 100644
--- a/addons/web/static/src/js/views/basic/basic_model.js
+++ b/addons/web/static/src/js/views/basic/basic_model.js
@@ -809,6 +809,7 @@ var BasicModel = AbstractModel.extend({
                 this.discardChanges(id, {rollback: false});
             }
         } else if (element._changes) {
+            delete element.tempLimitIncrement;
             _.each(element._changes, function (change) {
                 delete change.isNew;
             });
@@ -1683,6 +1684,10 @@ var BasicModel = AbstractModel.extend({
             case 'CREATE':
                 var options = {position: command.position};
                 def = this._addX2ManyDefaultRecord(list, options).then(function (id) {
+                    if (command.position === 'bottom' && list.orderedResIDs.length >= list.limit) {
+                        list.tempLimitIncrement = (list.tempLimitIncrement || 0) + 1;
+                        list.limit += 1;
+                    }
                     // FIXME: hack for lunch widget, which does useless default_get and onchange
                     if (command.data) {
                         return self._applyChange(id, command.data);
@@ -3819,7 +3824,8 @@ var BasicModel = AbstractModel.extend({
             // generate the current count and res_ids list by applying the changes
             var currentCount = list.count;
             var currentResIDs = list.res_ids;
-            var upperBound = list.limit ? Math.min(list.offset + list.limit, currentCount) : currentCount;
+            var effectiveLimit = (list.limit || 0) - (list.tempLimitIncrement || 0);
+            var upperBound = effectiveLimit ? Math.min(list.offset + effectiveLimit, currentCount) : currentCount;
             var fieldNames = list.getFieldNames();
             for (var i = list.offset; i < upperBound; i++) {
                 var resId = currentResIDs[i];