jsonrpc: add deprecations command to locally set deprecated apis on/off.

This command allows more fine-grained testing, without having to change the config of the
lightning node.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Added: JSON-RPC: `deprecations` to enable/disable deprecated APIs from this caller.

doc/Makefile

@@ -40,6 +40,7 @@ MANPAGES := doc/lightning-cli.1 \
 	doc/lightning-delforward.7 \
 	doc/lightning-delinvoice.7 \
 	doc/lightning-delpay.7 \
+	doc/lightning-deprecations.7 \
 	doc/lightning-disableinvoicerequest.7 \
 	doc/lightning-disableoffer.7 \
 	doc/lightning-disconnect.7 \

doc/index.rst

@@ -46,6 +46,7 @@ Core Lightning Documentation
    lightning-delforward <lightning-delforward.7.md>
    lightning-delinvoice <lightning-delinvoice.7.md>
    lightning-delpay <lightning-delpay.7.md>
+   lightning-deprecations <lightning-deprecations.7.md>
    lightning-disableinvoicerequest <lightning-disableinvoicerequest.7.md>
    lightning-disableoffer <lightning-disableoffer.7.md>
    lightning-disconnect <lightning-disconnect.7.md>

doc/lightning-deprecations.7.md

@@ -0,0 +1,49 @@
+lightning-deprecations -- Command to enable/disable deprecated APIs
+===================================================================
+
+SYNOPSIS
+--------
+
+**deprecations** *enable*
+
+DESCRIPTION
+-----------
+
+(Added *v24.02*)
+
+The **deprecations** RPC command overrides the global `allow-deprecated-apis` flag for further RPC commands on this same connection.  In particular, setting *enable* to `false` will neither accept deprecated parameters or commands, nor output
+deprecated fields.
+
+This is equivalent to the config option `allow-deprecated-apis`, but can
+be used on useful for developer testing to ensure you don't accidentally rely on
+deprecated features.
+
+
+EXAMPLE JSON REQUEST
+--------------------
+```json
+{
+  "id": 82,
+  "method": "deprecations",
+  "params": {
+     "enable": false
+  }
+}
+```
+
+RETURN VALUE
+------------
+
+On failure, one of the following error codes may be returned:
+
+- -32602: Error in given parameters.
+
+AUTHOR
+------
+
+Rusty Russell <<rusty@blockstream.com>> wrote the initial version of this man page.
+
+RESOURCES
+---------
+
+Main web site: <https://github.com/ElementsProject/lightning>

lightningd/jsonrpc.c

@@ -93,6 +93,9 @@ struct json_connection {
 	jsmn_parser input_parser;
 	jsmntok_t *input_toks;
 
+	/* Local deprecated support? */
+	bool deprecated_ok;
+
 	/* Our commands */
 	struct list_head commands;
 
@@ -654,6 +657,8 @@ struct json_filter **command_filter_ptr(struct command *cmd)
 
 static bool command_deprecated_ok(const struct command *cmd)
 {
+	if (cmd->jcon)
+		return cmd->jcon->deprecated_ok;
 	return cmd->ld->deprecated_apis;
 }
 
@@ -1332,6 +1337,7 @@ static struct io_plan *jcon_connected(struct io_conn *conn,
 	jcon->input_toks = toks_alloc(jcon);
 	jcon->notifications_enabled = false;
 	jcon->db_batching = false;
+	jcon->deprecated_ok = ld->deprecated_apis;
 	list_head_init(&jcon->commands);
 
 	/* We want to log on destruction, so we free this in destructor. */
@@ -1750,3 +1756,29 @@ static const struct json_command batching_command = {
 	"Database transaction batching {enable}",
 };
 AUTODATA(json_command, &batching_command);
+
+static struct command_result *json_deprecations(struct command *cmd,
+						const char *buffer,
+						const jsmntok_t *obj UNNEEDED,
+						const jsmntok_t *params)
+{
+	bool *enable;
+
+	if (!param(cmd, buffer, params,
+		   p_req("enable", param_bool, &enable),
+		   NULL))
+		return command_param_failed();
+
+	/* Catch the case where they sent this command then hung up. */
+	if (cmd->jcon)
+		cmd->jcon->deprecated_ok = *enable;
+	return command_success(cmd, json_stream_success(cmd));
+}
+
+static const struct json_command deprecations_command = {
+	"deprecations",
+	"utility",
+	json_deprecations,
+	"Set/unset deprecated APIs on this JSON connection (for developer testing)",
+};
+AUTODATA(json_command, &deprecations_command);