[FIX] web_kanban: fix race condition in do_search

The do_search method still had a race condition because the
read_slice method of datasets alter ids.  So, what could happen is
this: a long search is started, then a shorter search is started and
ended before the first search is completed.  The ui is rendered
properly, but then the long search ends and alter the dataset.  As
a result, the Kanban view is broken (cannot open a record anymore
because the dataset has the wrong ids).

This commit fixes the issue by doing basically what the read_slice
method did, except the ids altering part.  However, it introduced
a new problem for x2many kanban views: these kanban view don't have
the same dataset, they have a datasetstatic. The naive substitution
does not work, so I had to reintroduce the old method in X2ManyKanbanView.

addons/web_kanban/static/src/js/kanban_relational.js

@@ -15,6 +15,22 @@ var X2ManyKanbanView = KanbanView.extend({
         });
         this._super($node, options);
     },
+    load_records: function (offset, dataset) {
+        var options = {
+            'limit': this.limit,
+            'offset': offset,
+        };
+        dataset = dataset || this.dataset;
+        return dataset
+            .read_slice(this.fields_keys.concat(['__last_update']), options)
+            .then(function(records) {
+                return {
+                    records: records,
+                    is_empty: !records.length,
+                    grouped: false,
+                };
+            });
+    },    
 });
 
 var One2ManyKanbanView = X2ManyKanbanView.extend({
@@ -86,4 +102,3 @@ core.view_registry.add('one2many_kanban', One2ManyKanbanView);
 core.view_registry.add('many2many_kanban', Many2ManyKanbanView);
 
 });
-

addons/web_kanban/static/src/js/kanban_view.js

@@ -130,13 +130,16 @@ var KanbanView = View.extend({
         return this.search_orderer
             .add(options.grouped ? this.load_groups(options) : this.load_records())
             .then(function (data) {
+                var new_ids;
                 _.extend(self, options);
                 if (options.grouped) {
-                    var new_ids = _.union.apply(null, _.map(data.groups, function (group) {
+                    new_ids = _.union.apply(null, _.map(data.groups, function (group) {
                         return group.dataset.ids;
                     }));
-                    self.dataset.alter_ids(new_ids);
+                } else {
+                    new_ids = _.pluck(data.records, 'id');
                 }
+                self.dataset.alter_ids(new_ids);
                 self.data = data;
             })
             .then(this.proxy('render'))
@@ -153,20 +156,18 @@ var KanbanView = View.extend({
     },
 
     load_records: function (offset, dataset) {
-        var options = {
-            'limit': this.limit,
-            'offset': offset,
-        };
         dataset = dataset || this.dataset;        
-        return dataset
+        return dataset._model.query(this.fields_keys.concat(['__last_update']))
-            .read_slice(this.fields_keys.concat(['__last_update']), options)
+                .limit(this.limit || false)
-            .then(function(records) {
+                .offset(offset || 0)
-                return {
+                .all()
-                    records: records,
+                .then(function (records) {
-                    is_empty: !records.length,
+                    return {
-                    grouped: false,
+                        records: records,
-                };
+                        is_empty: !records.length,
-            });
+                        grouped: false,
+                    };
+                });
     },
 
     load_groups: function (options) {