lightningd: remove blinding field from onion_message_recv hook.

Changelog-Removed: Plugins: `onion_message_recv` hook `blinding` field (use `first_path_key` as per modern BOLT 4 naming).
Signed-off-by: Rusty Russell <[email protected]>

Author: rustyrussell

doc/developers-guide/deprecated-features.md

@@ -8,7 +8,6 @@ hidden: false
 | Name                                 | Type               | First Deprecated | Last Supported | Description                                                                                                                                                                     |
 |--------------------------------------|--------------------|------------------|----------------|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
 | listpeers.features.option_anchors_zero_fee_htlc_tx | Field | v24.08          | v25.09         | Renamed to `option_anchors` in the spec: check for that in `features` instead                                                          |
-| onion_message_recv.blinding          | Hook Field         | v24.11           | v25.05         | Renamed to `first_path_key` in BOLT 4 (available in hook from v24.11)                                                                  |
 | decodepay                            | Command            | v24.11           | v25.12         | Use `decode` which is more powerful (since v23.05)                                                                                     |
 | close.tx                             | Field              | v24.11           | v25.12         | Use txs array instead                                                                                                                  |
 | close.txid                           | Field              | v24.11           | v25.12         | Use txids array instead                                                                                                                |

lightningd/onion_message.c

@@ -33,12 +33,6 @@ static void json_add_blindedpath(struct plugin *plugin,
 		json_add_short_channel_id(stream, "first_scid", path->first_node_id.scidd.scid);
 		json_add_u32(stream, "first_scid_dir", path->first_node_id.scidd.dir);
 	}
-	if (lightningd_deprecated_out_ok(plugin->plugins->ld,
-					 plugin->plugins->ld->deprecated_ok,
-					 "onion_message_recv", "blinding",
-					 "v24.11", "v25.05")) {
-		json_add_pubkey(stream, "blinding", &path->first_path_key);
-	}
 	json_add_pubkey(stream, "first_path_key", &path->first_path_key);
 	json_array_start(stream, "hops");
 	for (size_t i = 0; i < tal_count(path->path); i++) {