errors calling last_used_index without wildcard

Author: RCasatta

src/server/mod.rs

@@ -270,6 +270,7 @@ pub enum Error {
     NotYetImplemented,
     AddressCannotBeBlinded,
     TooManyAddresses,
+    DescriptorMustHaveWildcard,
 }
 
 impl std::fmt::Display for Error {

src/server/route.rs

@@ -438,6 +438,10 @@ fn parse_descriptor_query(
 
     let descriptor = be::Descriptor::from_str(&desc_str, network)?;
 
+    if !descriptor.has_wildcard() {
+        return Err(Error::DescriptorMustHaveWildcard);
+    }
+
     if is_testnet_or_regtest == descriptor.is_mainnet() {
         return Err(Error::WrongNetwork);
     }
@@ -720,11 +724,11 @@ async fn handle_last_used_index(
     let mut internal_last_used: Option<u32> = None;
 
     for desc in descriptor.into_single_descriptors().unwrap().iter() {
-        let is_single_address = !desc.has_wildcard();
-
         // Determine if this is external (0/*) or internal (1/*) chain
         let is_internal = desc.to_string().contains("/1/*");
 
+        // we don't need to check for no wildcard, since parse_descriptor_query guarantees we have wildcard
+
         let mut last_used_for_chain: Option<u32> = None;
 
         for batch in 0..MAX_BATCH {
@@ -746,7 +750,7 @@ async fn handle_last_used_index(
             }
 
             // If no activity in this batch and we've checked at least GAP_LIMIT addresses, stop
-            if !batch_has_activity || is_single_address {
+            if !batch_has_activity {
                 break;
             }
         }
@@ -909,7 +913,13 @@ pub async fn infallible_route(
                     .status(StatusCode::UNPROCESSABLE_ENTITY)
                     .body(Full::new(e.to_string().into()))
                     .unwrap()
+            } else if matches!(e, Error::DescriptorMustHaveWildcard) {
+                Response::builder()
+                    .status(StatusCode::BAD_REQUEST)
+                    .body(Full::new(e.to_string().into()))
+                    .unwrap()
             } else {
+                // TODO map many errors to specific status codes
                 Response::builder()
                     .status(StatusCode::INTERNAL_SERVER_ERROR)
                     .body(Full::new(e.to_string().into()))

tests/integration.rs

@@ -552,29 +552,12 @@ async fn do_test_last_used_index(test_env: waterfalls::test_env::TestEnv) {
     );
 
     // Test descriptor without wildcard (single address at index 0)
-    // This should not cause infinite loops and should return external=0 since that address was used
+    // This must error
     let no_wildcard_desc = format!("{prefix}wpkh({tpub}/0/0)");
-    let result_no_wildcard = client.last_used_index(&no_wildcard_desc).await.unwrap();
+    let result_no_wildcard = client.last_used_index(&no_wildcard_desc).await.unwrap_err();
     assert_eq!(
-        result_no_wildcard.external,
-        Some(0),
-        "Descriptor without wildcard (index 0) should find activity"
-    );
-    assert_eq!(
-        result_no_wildcard.internal, None,
-        "Descriptor without wildcard has no internal chain"
-    );
-
-    // Test descriptor without wildcard at an unused index (index 1)
-    // This should return None for external since no tx at index 1
-    let no_wildcard_unused_desc = format!("{prefix}wpkh({tpub}/0/1)");
-    let result_no_wildcard_unused = client
-        .last_used_index(&no_wildcard_unused_desc)
-        .await
-        .unwrap();
-    assert_eq!(
-        result_no_wildcard_unused.external, None,
-        "Descriptor without wildcard at unused index should return None"
+        result_no_wildcard.to_string(),
+        "last_used_index response is not 200 but: 400 body is: DescriptorMustHaveWildcard"
     );
 
     println!(