JSON-RPC: getmanifest passes allow-deprecated-apis flag.

This allows plugins to choose how to present things in getmanifest.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Added: plugins: `getmanifest` may now include "allow-deprecated-apis" boolean flag.
Changelog-Deprecated: plugins: `getmanifest` without any parameters; plugins should accept any parameters for future use.

contrib/plugins/fail/failtimeout.py

@@ -8,7 +8,7 @@ import sys
 import time
 
 
-def json_getmanifest(request):
+def json_getmanifest(request, **kwargs):
     # Timeout is 60 seconds, so wait more
     time.sleep(61)
     return {

doc/PLUGINS.md

@@ -57,9 +57,10 @@ interface.
 
 ### The `getmanifest` method
 
-The `getmanifest` method is required for all plugins and will be called on
-startup without any params. It MUST return a JSON object similar to
-this example:
+The `getmanifest` method is required for all plugins and will be
+called on startup with optionsl parameters (in particular, it may have
+`allow-deprecated-apis: false`, but you should accept others).  It
+MUST return a JSON object similar to this example:
 
 ```json
 {

lightningd/plugin.c

@@ -1285,6 +1285,9 @@ const char *plugin_send_getmanifest(struct plugin *p)
 	p->stdin_conn = io_new_conn(p, stdin, plugin_stdin_conn_init, p);
 	req = jsonrpc_request_start(p, "getmanifest", p->log,
 				    plugin_manifest_cb, p);
+	/* Adding allow-deprecated-apis is part of the deprecation cycle! */
+	if (!deprecated_apis)
+		json_add_bool(req->stream, "allow-deprecated-apis", deprecated_apis);
 	jsonrpc_request_end(req);
 	plugin_request_send(p, req);
 	p->plugin_state = AWAITING_GETMANIFEST_RESPONSE;