Merge #128: Check if psbt is final, before broadcasting

110be3f check if psbt is final, before broadcasting (rajarshimaitra)

Pull request description:

  <!-- You can erase any parts of this template not applicable to your Pull Request. -->

  ### Description

  Fixes #97

  Add a finalizer check before broadcasting psbts.

  ### Checklists

  #### All Submissions:

  * [x] I've signed all my commits
  * [x] I followed the [contribution guidelines](https://github.com/bitcoindevkit/bdk-cli/blob/master/CONTRIBUTING.md)
  * [x] I ran `cargo fmt` and `cargo clippy` before committing

ACKs for top commit:
  notmandatory:
    tACK 110be3f

Tree-SHA512: 898908062bbfbe90ed296afbd83179066bfc2cb42538b3ff1c91a6da6c174ec4dbb0cd013dd766ec12ea944b7f0673ad36552aa0a423d2afbc94edcf43084d5c

src/handlers.rs

@@ -331,6 +331,7 @@ where
                 (Some(psbt), None) => {
                     let psbt = base64::decode(&psbt).map_err(|e| Error::Generic(e.to_string()))?;
                     let psbt: PartiallySignedTransaction = deserialize(&psbt)?;
+                    is_final(&psbt)?;
                     psbt.extract_tx()
                 }
                 (None, Some(tx)) => deserialize(&Vec::<u8>::from_hex(&tx)?)?,
@@ -388,6 +389,37 @@ where
     }
 }
 
+/// Determine if PSBT has final script sigs or witnesses for all unsigned tx inputs.
+#[cfg(any(
+    feature = "electrum",
+    feature = "esplora",
+    feature = "compact_filters",
+    feature = "rpc"
+))]
+pub(crate) fn is_final(psbt: &PartiallySignedTransaction) -> Result<(), Error> {
+    let unsigned_tx_inputs = psbt.unsigned_tx.input.len();
+    let psbt_inputs = psbt.inputs.len();
+    if unsigned_tx_inputs != psbt_inputs {
+        return Err(Error::Generic(format!(
+            "Malformed PSBT, {} unsigned tx inputs and {} psbt inputs.",
+            unsigned_tx_inputs, psbt_inputs
+        )));
+    }
+    let sig_count = psbt.inputs.iter().fold(0, |count, input| {
+        if input.final_script_sig.is_some() || input.final_script_witness.is_some() {
+            count + 1
+        } else {
+            count
+        }
+    });
+    if unsigned_tx_inputs > sig_count {
+        return Err(Error::Generic(
+            "The PSBT is not finalized, inputs are are not fully signed.".to_string(),
+        ));
+    }
+    Ok(())
+}
+
 /// Handle a key sub-command
 ///
 /// Key sub-commands are described in [`KeySubCommand`].
@@ -714,3 +746,28 @@ pub(crate) fn handle_command(cli_opts: CliOpts) -> Result<String, Error> {
     };
     result.map_err(|e| e.into())
 }
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use bdk::bitcoin::psbt::PartiallySignedTransaction;
+    use std::str::FromStr;
+
+    #[cfg(any(
+        feature = "electrum",
+        feature = "esplora",
+        feature = "compact_filters",
+        feature = "rpc"
+    ))]
+    #[test]
+    fn test_psbt_is_final() {
+        let unsigned_psbt = PartiallySignedTransaction::from_str("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").unwrap();
+        assert!(is_final(&unsigned_psbt).is_err());
+
+        let part_signed_psbt = PartiallySignedTransaction::from_str("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").unwrap();
+        assert!(is_final(&part_signed_psbt).is_err());
+
+        let full_signed_psbt = PartiallySignedTransaction::from_str("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").unwrap();
+        assert!(is_final(&full_signed_psbt).is_ok());
+    }
+}