Checkmk Werk 13094: Various ValueSpec-related API cleanups

ID: 13094 Title: Various ValueSpec-related API cleanups Component: Checks & agents Level: 2 Class: New feature Version: 2.2.0i1 Various changes have been done to <tt>ValueSpec</tt> and its subclasses, improving maintainability and robustness. If you don't write your own complicated <tt>ValueSpec</tt> subclasses and you don't have any self-written complicated check parameters, you are probably not affected. <ul> <li> <tt>ValueSpec</tt>'s constructor doesn't accept any random unspecifed keyword arguments anymore. It is better to raise an exception at the incorrect call site than silently accepting every typo. To fix any problems with this change, just remove the offending keyword arguments, they served no purpose after all. </li> <li> <tt>ValueSpec.canonical_value()</tt> is an abstract method now, otherwise we force lots of places to handle <tt>None</tt>. Previously quite a few things worked only more or less by accident. If you implement your own <tt>ValueSpec</tt> subclass, you have to implement that method now, unless an intermediate class already does it for you. </li> <li> <tt>DropdownChoice</tt> and <tt>CascadingDropdown</tt> don't have a <tt>no_preselect</tt> keyword argument anymore. It was redundant, because <tt>no_preselect_title</tt> is enough: If this keyword argument is not <tt>None</tt>, <tt>no_preselect=True</tt> is implied. Previously one could specify nonsensical combinations of those arguments. To fix any problems with this change, just drop the <tt>no_preselect</tt> keyword argument. </li> <li> <tt>Alternative</tt>, <tt>UploadOrPasteTextFile</tt>, <tt>TextOrRegExp</tt>, and <tt>CAorCAChain</tt> don't have a <tt>style</tt> keyword argument anymore. It didn't serve any purpose since Checkmk 2.0. Just remove it. </li> </ul>