[dbmanager] don't ignore field modifiers (e.g. length or geometry

definition) when updating it (fix #27613)

python/plugins/db_manager/db_plugins/plugin.py

@@ -1179,7 +1179,6 @@ class TableField(TableSubItemObject):
         if self.default2String() == new_default_str:
             new_default_str = None
         if self.comment == new_comment:
-            # Update also a new_comment
             new_comment = None
         ret = self.table().database().connector.updateTableColumn((self.table().schemaName(), self.table().name),
                                                                   self.name, new_name, new_type_str,

python/plugins/db_manager/dlg_field_properties.py

@@ -71,15 +71,13 @@ class DlgFieldProperties(QDialog, Ui_Dialog):
         fld.notNull = not self.chkNull.isChecked()
         fld.default = self.editDefault.text()
         fld.hasDefault = fld.default != ""
-        # Get the comment from the LineEdit
         fld.comment = self.editCom.text()
-        try:
-            modifier = int(self.editLength.text())
-        except ValueError:
-            ok = False
+        # length field also used for geometry definition, so we should
+        # not cast its value to int
+        if self.editLength.text() != "":
+            fld.modifier = self.editLength.text()
         else:
-            ok = True
-        fld.modifier = modifier if ok else None
+            fld.modifier = None
         return fld
 
     def onOK(self):