wallet: make p2tr the default address for newaddr.

Of course we still have to return a `bech32` for the deprecation period.

Changelog-Added: JSON-RPC: `newaddr` will now return a `p2tr` field by default.
Changelog-Deprecated: JSON-RPC: `newaddr` returning a `bech32` field if `addresstype` is not specified (use `p2tr`).
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

Author: rustyrussell

contrib/msggen/msggen/schema.json

@@ -27137,7 +27137,7 @@
             "description": [
               "It specifies the type of address wanted; currently *bech32* (e.g. `tb1qu9j4lg5f9rgjyfhvfd905vw46eg39czmktxqgg` on bitcoin testnet or `bc1qwqdg6squsna38e46795at95yu9atm8azzmyvckulcc7kytlcckxswvvzej` on bitcoin mainnet), or *p2tr* taproot addresses. The special value *all* generates all known address types for the same underlying key."
             ],
-            "default": "*bech32* address",
+            "default": "*p2tr* address",
             "enum": [
               "bech32",
               "p2tr",

doc/developers-guide/deprecated-features.md

@@ -21,7 +21,8 @@ hidden: false
 | channel_state_changed.null_scid                    | Notification Field | v25.09           | v26.09         | In channel_state_changed notification, `short_channel_id` will be missing instead of `null`                               |
 | notification.payload                               | Notification Field | v25.09           | v26.09         | Notifications from plugins used to have fields in `payload` sub-object, now they are not (just like normal notifications) |
 | pay_notifications.raw_fields                       | Field              | v25.09           | v26.09         | `channel_hint_update`, `pay_failure` and `pay_success` notifications now wrap members in an object of the same name       |
-| encrypted_hsm	                                     | Config             | v25.12           | v26.12         | `hsm-passphrase` is a name which also makes sense for modern hsm_secrets which use BIP 39                                 |
+| encrypted_hsm                                      | Config             | v25.12           | v26.12         | `hsm-passphrase` is a name which also makes sense for modern hsm_secrets which use BIP 39                                 |
+| newaddr.addresstype.defaultbech32                  | Parameter          | v25.12           | v26.12         | Use `p2tr` in the response (present since v23.08 if `addresstype` is `p2tr`,  and always present since v24.12).           |
 
 Inevitably there are features which need to change: either to be generalized, or removed when they can no longer be supported.
 

doc/schemas/newaddr.json

@@ -19,7 +19,7 @@
         "description": [
           "It specifies the type of address wanted; currently *bech32* (e.g. `tb1qu9j4lg5f9rgjyfhvfd905vw46eg39czmktxqgg` on bitcoin testnet or `bc1qwqdg6squsna38e46795at95yu9atm8azzmyvckulcc7kytlcckxswvvzej` on bitcoin mainnet), or *p2tr* taproot addresses. The special value *all* generates all known address types for the same underlying key."
         ],
-        "default": "*bech32* address",
+        "default": "*p2tr* address",
         "enum": [
           "bech32",
           "p2tr",

wallet/walletrpc.c

@@ -149,10 +149,19 @@ static struct command_result *json_newaddr(struct command *cmd,
 	char *bech32, *p2tr;
 
 	if (!param(cmd, buffer, params,
-		   p_opt_def("addresstype", param_newaddr, &addrtype, ADDR_BECH32),
+		   p_opt("addresstype", param_newaddr, &addrtype),
 		   NULL))
 		return command_param_failed();
 
+	if (!addrtype) {
+		addrtype = tal(cmd, enum addrtype);
+		if (command_deprecated_in_ok(cmd, "addresstype.defaultbech32",
+					     "v25.12", "v26.12"))
+			*addrtype = ADDR_ALL;
+		else
+			*addrtype = ADDR_P2TR;
+	}
+
 	if (!newaddr_inner(cmd, &pubkey, *addrtype)) {
 		return command_fail(cmd, LIGHTNINGD, "Keys exhausted ");
 	};