splice: Move splice to experimental feature bit

This was recommended by @t-bast: if the final spec commits to something
compatible, we can simply advertize and accept both features, but if it
does change in incompatible ways we won't cause problems for nodes
who implement the official spec.

(I split this, so first, we remove the OPT_SPLICE entirely, to make
sure we caught them all. --RR)

Suggested-by: @t-bast
Changelog-None

channeld/channeld.c

@@ -1494,7 +1494,7 @@ static u8 *send_commit_part(struct peer *peer,
 	 * send unless negotiated */
 	if (feature_negotiated(peer->our_features,
 			       peer->their_features,
-			       OPT_SPLICE)) {
+			       OPT_EXPERIMENTAL_SPLICE)) {
 		status_debug("send_commit_part(splice: %d, remote_splice: %d)",
 			     (int)splice_amnt, (int)remote_splice_amnt);
 

common/features.c

@@ -142,7 +142,7 @@ static const struct feature_style feature_styles[] = {
 	{ OPT_PROVIDE_PEER_BACKUP_STORAGE,
 	  .copy_style = { [INIT_FEATURE] = FEATURE_REPRESENT,
 			  [NODE_ANNOUNCE_FEATURE] = FEATURE_REPRESENT } },
-	{ OPT_SPLICE,
+	{ OPT_EXPERIMENTAL_SPLICE,
 	  .copy_style = { [INIT_FEATURE] = FEATURE_REPRESENT,
 			  [NODE_ANNOUNCE_FEATURE] = FEATURE_REPRESENT,
 			  [CHANNEL_FEATURE] = FEATURE_DONT_REPRESENT} },
@@ -491,6 +491,41 @@ const char *feature_name(const tal_t *ctx, size_t f)
 		NULL,
 		NULL,
 		NULL, /* 100/101 */
+		NULL,
+		NULL,
+		NULL,
+		NULL,
+		NULL, /* 110/111 */
+		NULL,
+		NULL,
+		NULL,
+		NULL,
+		NULL, /* 120/121 */
+		NULL,
+		NULL,
+		NULL,
+		NULL,
+		NULL, /* 130/131 */
+		NULL,
+		NULL,
+		NULL,
+		NULL,
+		NULL, /* 140/141 */
+		NULL,
+		NULL,
+		NULL,
+		NULL,
+		NULL, /* 150/151 */
+		NULL,
+		NULL,
+		NULL,
+		NULL,
+		NULL, /* 160/161 */
+		"option_experimental_splice", /* https://github.com/lightning/bolts/pull/863 */
+		NULL,
+		NULL,
+		NULL,
+		NULL, /* 170/171 */
 	};
 
 	if (f / 2 >= ARRAY_SIZE(fnames) || !fnames[f / 2])

common/features.h

@@ -136,7 +136,11 @@ struct feature_set *feature_set_dup(const tal_t *ctx,
 #define OPT_SHUTDOWN_ANYSEGWIT			26
 #define OPT_CHANNEL_TYPE			44
 #define OPT_PAYMENT_METADATA			48
-#define OPT_SPLICE				62
+
+/* BOLT-splice #9:
+ * | 62/63 | `option_splice` |  ... IN ...
+ */
+#define OPT_EXPERIMENTAL_SPLICE			162
 
 /* BOLT-f53ca2301232db780843e894f55d95d512f297f9 #9:
  * | 28/29 | `option_dual_fund` | ... IN9 ...

contrib/pyln-client/pyln/client/gossmap.py

@@ -74,6 +74,7 @@ class LnFeatureBits(object):
     OPTION_PROPOSED_UPFRONT_FEE = 56                # IN9       #1052
     OPTION_PROPOSED_CLOSING_REJECTED = 60           # IN        #1016
     OPTION_PROPOSED_SPLICE = 62                     # IN        #863
+    OPTION_PROPOSED_EXPERIMENTAL_SPLICE = 162       # IN        #863
 
 
 def _parse_features(featurebytes):

lightningd/channel_control.c

@@ -1869,7 +1869,7 @@ static struct command_result *param_channel_for_splice(struct command *cmd,
 
 	if (!feature_negotiated(cmd->ld->our_features,
 			        (*channel)->peer->their_features,
-				OPT_SPLICE))
+				OPT_EXPERIMENTAL_SPLICE))
 		return command_fail(cmd, SPLICE_NOT_SUPPORTED,
 				    "splicing not supported");
 

lightningd/options.c

@@ -1196,7 +1196,7 @@ static char *opt_set_splicing(struct lightningd *ld)
 						    OPTIONAL_FEATURE(OPT_QUIESCE))));
 	feature_set_or(ld->our_features,
 		       take(feature_set_for_feature(NULL,
-						    OPTIONAL_FEATURE(OPT_SPLICE))));
+						    OPTIONAL_FEATURE(OPT_EXPERIMENTAL_SPLICE))));
 	return NULL;
 }
 
@@ -1911,7 +1911,7 @@ void add_config_deprecated(struct lightningd *ld,
 			json_add_bool(response, name0,
 				      feature_offered(ld->our_features
 						      ->bits[INIT_FEATURE],
-						      OPT_SPLICE));
+						      OPT_EXPERIMENTAL_SPLICE));
 		} else if (opt->cb == (void *)opt_set_onion_messages) {
 			json_add_bool(response, name0,
 				      feature_offered(ld->our_features

tests/utils.py

@@ -44,7 +44,7 @@ def expected_peer_features(wumbo_channels=False, extra=[]):
         features += [29]
     if EXPERIMENTAL_SPLICING:
         features += [35]  # option_quiesce
-        features += [63]  # option_splice
+        features += [163]  # option_experimental_splice
     return hex_bits(features + extra)
 
 
@@ -60,7 +60,7 @@ def expected_node_features(wumbo_channels=False, extra=[]):
         features += [29]
     if EXPERIMENTAL_SPLICING:
         features += [35]  # option_quiesce
-        features += [63]  # option_splice
+        features += [163]  # option_experimental_splice
     return hex_bits(features + extra)