input/tidal: deprecated because Tidal has changed the protocol

NEWS

 ver 0.21.11 (not yet released)
+* input
+  - tidal: deprecated because Tidal has changed the protocol
 * decoder
   - wildmidi: log error if library initialization fails
 * output

doc/plugins.rst

@@ -245,6 +245,11 @@ tidal
 
 Play songs from the commercial streaming service `Tidal <http://tidal.com/>`_. It plays URLs in the form tidal://track/ID, e.g.:
 
+.. warning::
+
+   This plugin is currently defunct because Tidal has changed the
+   protocol and decided not to share documentation.
+
 .. code-block:: none
 
     mpc add tidal://track/59727857

src/input/plugins/TidalInputPlugin.cxx

@@ -180,6 +180,8 @@ InitTidalInput(EventLoop &event_loop, const ConfigBlock &block)
 	if (password == nullptr)
 		throw PluginUnavailable("No Tidal password configured");
 
+	FormatWarning(tidal_domain, "The Tidal input plugin is deprecated because Tidal has changed the protocol and doesn't share documentation");
+
 	tidal_audioquality = block.GetBlockValue("audioquality", "HIGH");
 
 	tidal_session = new TidalSessionManager(event_loop, base_url, token,