server.version: server must ignore extraneous args, to allow future ext

Author: SomberNight

docs/protocol-changes.rst

@@ -194,6 +194,8 @@ Changes
   * Breaking change for the version negotiation: we now mandate that
     the :func:`server.version` message must be the first message sent.
     That is, version negotiation must happen before any other messages.
+  * Also for :func:`server.version`, the server must tolerate and ignore
+    extraneous arguments, to allow for extensions in future protocol versions.
   * The status of a scripthash has its definition tightened in a
     backwards-compatible way: mempool txs now have a canonical ordering
     defined for the calculation (previously their order was undefined).

docs/protocol-methods.rst

@@ -1122,6 +1122,8 @@ Only the first :func:`server.version` message is accepted.
 **Signature**
 
   .. function:: server.version(client_name="", protocol_version="1.4")
+  .. versionchanged:: 1.6
+     server must tolerate and ignore extraneous args
 
   * *client_name*
 
@@ -1134,6 +1136,9 @@ Only the first :func:`server.version` message is accepted.
     they can be passed as a single string rather than as an array of
     two strings, as for the default value.
 
+  Extraneous unknown args MUST be tolerated and ignored by the server,
+  to allow for future extensions.
+
   The server should use the highest protocol version both support::
 
     version = min(client.protocol_max, server.protocol_max)
@@ -1163,6 +1168,16 @@ Only the first :func:`server.version` message is accepted.
 
   ["ElectrumX 1.2.1", "1.2"]
 
+**Example**
+
+  Redundant unknown arguments MUST be ignored and tolerated by the server::
+
+    server.version("electrum/4.6.2", ["1.4", "1.6"], "trailing_garbage1", 9999.9, "dd": {})
+
+**Example Result**::
+
+  ["ElectrumX 1.18.0", "1.4"]
+
 
 Some more stuff for altcoins
 ============================