Adding threshold error on exceeding 1000 ways

Signed-off-by: Harshil Jani <harshiljani2002@gmail.com>

Author: Harshil-Jani

src/descriptor/mod.rs

@@ -616,6 +616,11 @@ impl Descriptor<DescriptorPublicKey> {
 
     /// Get all possible assets for a given descriptor
     pub fn get_all_assets(&self) -> Result<Vec<Assets>, Error> {
+        let threshold = self.count_assets();
+        if threshold >= 1000 {
+            return Err(Error::MaxAssetThresholdExceeded);
+        }
+
         match self {
             Descriptor::Bare(k) => Ok(k.as_inner().get_all_assets()),
             Descriptor::Pkh(k) => {

src/lib.rs

@@ -560,6 +560,8 @@ pub enum Error {
     /// At least two BIP389 key expressions in the descriptor contain tuples of
     /// derivation indexes of different lengths.
     MultipathDescLenMismatch,
+    /// Cannot get assets for this large descriptor. Exceeds 1000 assets.
+    MaxAssetThresholdExceeded,
 }
 
 // https://github.com/sipa/miniscript/pull/5 for discussion on this number
@@ -636,6 +638,7 @@ impl fmt::Display for Error {
             Error::TrNoScriptCode => write!(f, "No script code for Tr descriptors"),
             Error::TrNoExplicitScript => write!(f, "No script code for Tr descriptors"),
             Error::MultipathDescLenMismatch => write!(f, "At least two BIP389 key expressions in the descriptor contain tuples of derivation indexes of different lengths"),
+            Error::MaxAssetThresholdExceeded => write!(f,"Cannot plan descriptors having more than 1000 possible spend paths."),
         }
     }
 }
@@ -678,6 +681,7 @@ impl error::Error for Error {
             | TrNoScriptCode
             | TrNoExplicitScript
             | MultipathDescLenMismatch => None,
+            MaxAssetThresholdExceeded => None,
             Script(e) => Some(e),
             AddrError(e) => Some(e),
             BadPubkey(e) => Some(e),