JSON-API: `fundchannel_start` uses `amount` fieldname to replace `satoshi`

contrib/pylightning/lightning/lightning.py

@@ -540,9 +540,22 @@ class LightningRpc(UnixDomainSocketRpc):
 
         return _fundchannel(node_id, *args, **kwargs)
 
-    def fundchannel_start(self, node_id, satoshi, feerate=None, announce=True):
+    def _deprecated_fundchannel_start(self, node_id, satoshi, feerate=None, announce=True):
+        warnings.warn("fundchannel_start: the 'satoshi' field is renamed 'amount' : expect removal"
+                      " in Mid-2020",
+                      DeprecationWarning)
+
+        payload = {
+            "id": node_id,
+            "satoshi": satoshi,
+            "feerate": feerate,
+            "announce": announce,
+        }
+        return self.call("fundchannel_start", payload)
+
+    def fundchannel_start(self, node_id, *args, **kwargs):
         """
-        Start channel funding with {id} for {satoshi} satoshis
+        Start channel funding with {id} for {amount} satoshis
         with feerate of {feerate} (uses default feerate if unset).
         If {announce} is False, don't send channel announcements.
         Returns a Bech32 {funding_address} for an external wallet
@@ -550,13 +563,20 @@ class LightningRpc(UnixDomainSocketRpc):
         'fundchannel_complete' to complete channel establishment
         with peer.
         """
-        payload = {
-            "id": node_id,
-            "satoshi": satoshi,
-            "feerate": feerate,
-            "announce": announce,
-        }
-        return self.call("fundchannel_start", payload)
+
+        if 'satoshi' in kwargs:
+            return self._deprecated_fundchannel_start(node_id, *args, **kwargs)
+
+        def _fundchannel_start(node_id, amount, feerate=None, announce=True):
+            payload = {
+                "id": node_id,
+                "amount": amount,
+                "feerate": feerate,
+                "announce": announce
+            }
+            return self.call("fundchannel_start", payload)
+
+        return _fundchannel_start(node_id, *args, **kwargs)
 
     def fundchannel_cancel(self, node_id):
         """

lightningd/opening_control.c

@@ -26,6 +26,7 @@
 #include <lightningd/log.h>
 #include <lightningd/notification.h>
 #include <lightningd/opening_control.h>
+#include <lightningd/options.h>
 #include <lightningd/peer_control.h>
 #include <lightningd/plugin_hook.h>
 #include <lightningd/subd.h>
@@ -1069,16 +1070,41 @@ static struct command_result *json_fund_channel_start(struct command *cmd,
 	fc->cancels = tal_arr(fc, struct command *, 0);
 	fc->uc = NULL;
 	fc->inflight = false;
-	if (!param(fc->cmd, buffer, params,
-		   p_req("id", param_node_id, &id),
-		   p_req("satoshi", param_sat, &amount),
-		   p_opt("feerate", param_feerate, &feerate_per_kw),
-		   p_opt_def("announce", param_bool, &announce_channel, true),
-		   NULL))
-		return command_param_failed();
+
+	/* For generating help, give new-style. */
+	if (!params || !deprecated_apis || params->type == JSMN_ARRAY) {
+		if (!param(fc->cmd, buffer, params,
+			   p_req("id", param_node_id, &id),
+			   p_req("amount", param_sat, &amount),
+			   p_opt("feerate", param_feerate, &feerate_per_kw),
+			   p_opt_def("announce", param_bool, &announce_channel, true),
+			   NULL))
+			return command_param_failed();
+	} else {
+		/* For json object type when allow deprecated api, 'check' command
+		 * can't find the error if we don't set 'amount' nor 'satoshi'.
+		 */
+		struct amount_sat *satoshi;
+		if (!param(fc->cmd, buffer, params,
+			   p_req("id", param_node_id, &id),
+			   p_opt("amount", param_sat, &amount),
+			   p_opt("satoshi", param_sat, &satoshi),
+			   p_opt("feerate", param_feerate, &feerate_per_kw),
+			   p_opt_def("announce", param_bool, &announce_channel, true),
+			   NULL))
+			return command_param_failed();
+
+		if (!amount) {
+			if (satoshi)
+				amount = satoshi;
+			else
+				return command_fail(cmd, JSONRPC2_INVALID_PARAMS,
+						    "Need set 'amount' field");
+		}
+	}
 
 	if (amount_sat_greater(*amount, max_funding_satoshi))
-                return command_fail(cmd, FUND_MAX_EXCEEDED,
+		return command_fail(cmd, FUND_MAX_EXCEEDED,
 				    "Amount exceeded %s",
 				    type_to_string(tmpctx, struct amount_sat,
 						   &max_funding_satoshi));

plugins/fundchannel.c

@@ -312,7 +312,11 @@ static struct command_result *fundchannel_start(struct command *cmd,
 
 	json_out_start(ret, NULL, '{');
 	json_out_addstr(ret, "id", node_id_to_hexstr(tmpctx, fr->id));
-	json_out_addstr(ret, "satoshi", fr->funding_str);
+
+	if (deprecated_apis)
+		json_out_addstr(ret, "satoshi", fr->funding_str);
+	else
+		json_out_addstr(ret, "amount", fr->funding_str);
 
 	if (fr->feerate_str)
 		json_out_addstr(ret, "feerate", fr->feerate_str);