to_public method for descriptors

src/embit/descriptor/arguments.py

@@ -162,7 +162,7 @@ def __init__(self, key, origin=None, derivation=None, taproot=False):
         self.origin = origin
         self.key = key
         self.taproot = taproot
-        if not hasattr(key, "derive") and derivation is not None:
+        if not hasattr(key, "derive") and derivation:
             raise ArgumentError("Key %s doesn't support derivation" % key)
         self.allowed_derivation = derivation
 
@@ -335,6 +335,14 @@ def is_private(self):
             self.is_extended and self.key.is_private
         )
 
+    def to_public(self):
+        if not self.is_private:
+            return self
+        if isinstance(self.key, ec.PrivateKey):
+            return type(self)(self.key.get_public_key(), self.origin, self.allowed_derivation, self.taproot)
+        else:
+            return type(self)(self.key.to_public(), self.origin, self.allowed_derivation, self.taproot)
+
     @property
     def private_key(self):
         if not self.is_private:

src/embit/descriptor/descriptor.py

@@ -153,6 +153,22 @@ def derive(self, idx, branch_index=None):
                 None, self.sh, self.wsh, self.key.derive(idx, branch_index), self.wpkh, self.taproot
             )
 
+    def to_public(self):
+        if self.miniscript:
+            return type(self)(
+                self.miniscript.to_public(),
+                self.sh,
+                self.wsh,
+                None,
+                self.wpkh,
+                self.taproot,
+            )
+        else:
+            return type(self)(
+                None, self.sh, self.wsh, self.key.to_public(), self.wpkh, self.taproot
+            )
+
+
     def owns(self, psbt_scope):
         """Checks if psbt input or output belongs to this descriptor"""
         # we can't check if we don't know script_pubkey

src/embit/descriptor/miniscript.py

@@ -33,6 +33,13 @@ def derive(self, idx, branch_index=None):
         ]
         return type(self)(*args)
 
+    def to_public(self):
+        args = [
+            arg.to_public() if hasattr(arg, "to_public") else arg
+            for arg in self.args
+        ]
+        return type(self)(*args)
+
     def branch(self, branch_index):
         args = [
             arg.branch(branch_index) if hasattr(arg, "branch") else arg