fixes + small speed up for multi/sortedmulti scripts

shared/desc_utils.py

@@ -396,9 +396,8 @@ class Key:
     def key_bytes(self):
         kb = self.node.pubkey()
         if self.taproot:
-            if len(kb) == 33:
-                kb = kb[1:]
-            assert len(kb) == 32
+            # xonly
+            kb = kb[1:]
         return kb
 
     def extended_public_key(self):

shared/descriptor.py

@@ -236,20 +236,22 @@ class Descriptor:
         return self._keys
 
     def derive(self, idx=None, change=False):
-        # derive keys first
-        derived_keys = OrderedDict()
-        for i, k in enumerate(self.keys):
-            if not i and self.is_taproot:
-                # internal key is always at index 0 in self.keys
-                # ik is derived few lines later
-                continue
-            dk = k.derive(idx, change=change)
-            dk.taproot=self.is_taproot
-            derived_keys[k] = dk
-
         if self.is_taproot:
+            # derive keys first
+            # duplicate keys can be may be found in different leaves
+            # use map to derive each key just once
+            derived_keys = OrderedDict()
+            ikd = None
+            for i, k in enumerate(self.keys):
+                dk = k.derive(idx, change=change)
+                dk.taproot = self.is_taproot
+                derived_keys[k] = dk
+                if not i:
+                    # internal key is always at index 0 in self.keys
+                    ikd = dk
+
             return type(self)(
-                self.key.derive(idx, change=change),
+                ikd,
                 tapscript=self.tapscript.derive(idx, derived_keys, change=change),
                 addr_fmt=self.addr_fmt,
                 keys=list(derived_keys.values()),
@@ -257,9 +259,8 @@ class Descriptor:
         if self.miniscript:
             return type(self)(
                 None,
-                self.miniscript.derive(idx, derived_keys, change=change),
+                self.miniscript.derive(idx, change=change),
                 addr_fmt=self.addr_fmt,
-                keys=list(derived_keys.values())
             )
 
         # single-sig

shared/miniscript.py

@@ -662,9 +662,8 @@ class KeyHash(Key):
         return super().parse_key(k, *args, **kwargs)
 
     def serialize(self, *args, **kwargs):
-        if self.taproot:
-            return ngu.hash.hash160(self.node.pubkey()[1:33])
-        return ngu.hash.hash160(self.node.pubkey())
+        start = 1 if self.taproot else 0
+        return ngu.hash.hash160(self.node.pubkey()[start:33])
 
     def __len__(self):
         return 21 # <20:pkh>
@@ -1354,8 +1353,14 @@ class Multi(Miniscript):
     N_MAX = 20
 
     def inner_compile(self):
+        # scr = [arg.compile() for arg in self.args[1:]]
+        # optimization - it is all keys with known length (xonly keys not allowed here)
+        scr = [b'\x21' + arg.key_bytes() for arg in self.args[1:]]
+        if self.NAME == "sortedmulti":
+            scr.sort()
         return (
-            b"".join([arg.compile() for arg in self.args])
+            self.args[0].compile()
+            + b"".join(scr)
             + Number(len(self.args) - 1).compile()
             + b"\xae"
         )
@@ -1381,13 +1386,6 @@ class Sortedmulti(Multi):
     # <k> <key1> ... <keyn> <n> CHECKMULTISIG
     NAME = "sortedmulti"
 
-    def inner_compile(self):
-        return (
-            self.args[0].compile()
-            + b"".join(sorted([arg.compile() for arg in self.args[1:]]))
-            + Number(len(self.args) - 1).compile()
-            + b"\xae"
-        )
 
 class Multi_a(Multi):
     # <key1> CHECKSIG <key> CHECKSIGADD ... <keyn> CHECKSIGADD EQUALVERIFY
@@ -1398,12 +1396,19 @@ class Multi_a(Multi):
     def inner_compile(self):
         from opcodes import OP_CHECKSIGADD, OP_NUMEQUAL, OP_CHECKSIG
         script = b""
-        for i, key in enumerate(self.args[1:]):
-            script += key.compile()
+        # scr = [arg.compile() for arg in self.args[1:]]
+        # optimization - it is all keys with known length (only xonly keys allowed here)
+        scr = [b"\x20" + arg.key_bytes() for arg in self.args[1:]]
+        if self.NAME == "sortedmulti_a":
+            scr.sort()
+
+        for i, key in enumerate(scr):
+            script += key
             if i == 0:
                 script += bytes([OP_CHECKSIG])
             else:
                 script += bytes([OP_CHECKSIGADD])
+
         script += self.args[0].compile()  # M (threshold)
         script += bytes([OP_NUMEQUAL])
         return script
@@ -1417,19 +1422,6 @@ class Sortedmulti_a(Multi_a):
     # <key1> CHECKSIG <key> CHECKSIGADD ... <keyn> CHECKSIGADD EQUALVERIFY
     NAME = "sortedmulti_a"
 
-    def inner_compile(self):
-        from opcodes import OP_CHECKSIGADD, OP_NUMEQUAL, OP_CHECKSIG
-        script = b""
-        for i, key in enumerate(sorted([arg.compile() for arg in self.args[1:]])):
-            script += key
-            if i == 0:
-                script += bytes([OP_CHECKSIG])
-            else:
-                script += bytes([OP_CHECKSIGADD])
-        script += self.args[0].compile()  # M (threshold)
-        script += bytes([OP_NUMEQUAL])
-        return script
-
 
 class Pk(OneArg):
     # <key> CHECKSIG