refactor: Remove Error::DisconnectCommitTime

This error was thrown when a disconnected branch is populated during
construction of a CommitNode. The error was intended to inform users
that the disconnected branches are thrown away, but this information is
not useful. It is a general fact that CommitNode omits disconnected
branches. We don't need to throw a runtime error in case a disconnected
branch exists.

Removing Error::DisconnectedCommitTime eliminates a useless runtime
error path.

Author: uncomputable

src/lib.rs

@@ -78,8 +78,6 @@ pub fn leaf_version() -> elements::taproot::LeafVersion {
 pub enum Error {
     /// Decoder error
     Decode(decode::Error),
-    /// A disconnect node was populated at commitment time
-    DisconnectCommitTime,
     /// A disconnect node was *not* populated at redeem time
     DisconnectRedeemTime,
     /// Type-checking error
@@ -99,9 +97,6 @@ impl fmt::Display for Error {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
             Error::Decode(ref e) => fmt::Display::fmt(e, f),
-            Error::DisconnectCommitTime => {
-                f.write_str("disconnect node had two children (commit time); must have one")
-            }
             Error::DisconnectRedeemTime => {
                 f.write_str("disconnect node had one child (redeem time); must have two")
             }
@@ -119,7 +114,6 @@ impl std::error::Error for Error {
     fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
         match *self {
             Error::Decode(ref e) => Some(e),
-            Error::DisconnectCommitTime => None,
             Error::DisconnectRedeemTime => None,
             Error::Type(ref e) => Some(e),
             Error::Execution(ref e) => Some(e),

src/node/construct.rs

@@ -98,14 +98,10 @@ impl<J: Jet> ConstructNode<J> {
             fn convert_disconnect(
                 &mut self,
                 _: &PostOrderIterItem<&ConstructNode<J>>,
-                maybe_converted: Option<&Arc<CommitNode<J>>>,
+                _: Option<&Arc<CommitNode<J>>>,
                 _: &Option<Arc<ConstructNode<J>>>,
             ) -> Result<NoDisconnect, Self::Error> {
-                if maybe_converted.is_some() {
-                    Err(crate::Error::DisconnectCommitTime)
-                } else {
-                    Ok(NoDisconnect)
-                }
+                Ok(NoDisconnect)
             }
 
             fn convert_data(