[FIX] web: list: determine width according to widget

On a list with no data, the width of each column is determined by
a heuristic. Before this rev., the heuristic was based on the field
type. It now takes the potential widget set in the arch into
account, and fallbacks on the field type.

addons/web/static/src/js/views/list/list_editable_renderer.js

@@ -566,19 +566,21 @@ ListRenderer.include({
             // width.
             return 1;
         }
-        var widget = this.state.fieldsInfo.list[column.attrs.name].Widget.prototype;
-        if ('widthFactor' in widget) {
-            return widget.widthFactor;
-        }
-        switch (field.type) {
-            case 'boolean': return '40px';
-            case 'date': return '92px';
-            case 'datetime': return '146px';
-            case 'float': return '92px';
-            case 'integer': return '74px';
-            case 'monetary': return '104px';
-            default: return 1; // evenly distribute the remaining space
+        var widgetProto = this.state.fieldsInfo.list[column.attrs.name].Widget.prototype;
+        if ('widthFactor' in widgetProto) {
+            return widgetProto.widthFactor;
         }
+        var fixedWidthTypes = {
+            boolean: '40px',
+            date: '92px',
+            datetime: '146px',
+            float: '92px',
+            integer: '74px',
+            monetary: '104px',
+        };
+        var widget = this.state.fieldsInfo.list[column.attrs.name].widget;
+        var type = widget in fixedWidthTypes ? widget : field.type;
+        return fixedWidthTypes[type] || 1;
     },
     /**
      *

addons/web/static/tests/views/list_tests.js

@@ -1497,6 +1497,26 @@ QUnit.module('Views', {
         list.destroy();
     });
 
+    QUnit.test('column width should depend on the widget', async function (assert) {
+        assert.expect(1);
+
+        this.data.foo.records = []; // the width heuristic only applies when there are no records
+        var list = await createView({
+            View: ListView,
+            model: 'foo',
+            data: this.data,
+            arch: '<tree editable="top">' +
+                        '<field name="datetime" widget="date"/>' +
+                        '<field name="text"/>' +
+                    '</tree>',
+        });
+
+        assert.strictEqual(list.$('th[data-name="datetime"]')[0].offsetWidth, 92,
+            "should be the optimal width to display a date, not a datetime");
+
+        list.destroy();
+    });
+
     QUnit.test('row height should not change when switching mode', async function (assert) {
         // Warning: this test is css dependant
         assert.expect(3);