Ensure field is loaded before applying changes

For fields like xxx2Many the changed values are operation to apply on the
existing value. So we must be sure to have loaded the value.

issue9730
review314491002

src/model.js

@@ -622,11 +622,14 @@
         is_loaded: function(name) {
             return ((this.id < 0) || (name in this._loaded));
         },
-        load: function(name) {
+        load: function(name, async) {
             var fname;
             var prm;
+            if (async === undefined) {
+                async = true;
+            }
             if (this.is_loaded(name)) {
-                return jQuery.when();
+                return async? jQuery.when() : this.model.fields[name];
             }
             if (this.group.prm.state() == 'pending') {
                 return this.group.prm.then(function() {
@@ -751,9 +754,9 @@
                     context[this.model.name + '.' + fname] = 'size';
                 }
             }
-            prm = this.model.execute('read', [Object.keys(id2record).map(
+            var result = this.model.execute('read', [Object.keys(id2record).map(
                         function (e) { return parseInt(e, 10); }),
-                    fnames_to_fetch], context);
+                    fnames_to_fetch], context, async);
             var succeed = function(values, exception) {
                 if (exception === undefined) exception = false;
                 var id2value = {};
@@ -794,8 +797,17 @@
                 }
                 return succeed(failed_values, true);
             };
-            this.group.prm = prm.then(succeed, failed);
-            return this.group.prm;
+            if (async) {
+                this.group.prm = result.then(succeed, failed);
+                return this.group.prm;
+            } else {
+                if (result) {
+                    succeed(result);
+                } else {
+                    failed();
+                }
+                return this.model.fields[name];
+            }
         },
         set: function(values, validate) {
             if (validate === undefined) {
@@ -1130,7 +1142,7 @@
                 } catch (e) {
                     return;
                 }
-                this.model.fields[fieldname].set_on_change(this, result);
+                this.load(fieldname, false).set_on_change(this, result);
             }
         },
         set_on_change: function(values) {
@@ -1147,7 +1159,7 @@
                     var related = fieldname + '.';
                     this._values[related] = values[related] || {};
                 }
-                this.model.fields[fieldname].set_on_change(this, value);
+                this.load(fieldname, false).set_on_change(this, value);
             }
         },
         autocomplete_with: function(fieldname) {