Fix #2035 again

lib/src/trie/proof_decode.rs

@@ -1069,8 +1069,14 @@ impl<T: AsRef<[u8]>> DecodedTrieProof<T> {
                     // after the last entry of the trie.
                     return Ok(None);
                 };
+                let Ok(parent_entry_decoded) =
+                    trie_node::decode(&proof[self.entries[parent_entry].range_in_proof.clone()])
+                else {
+                    // Proof has been checked to be entirely decodable.
+                    unreachable!()
+                };
 
-                let Some(child_num) = iter_entry_decoded
+                let Some(child_num) = parent_entry_decoded
                     .children
                     .iter()
                     .skip(usize::from(parent_to_child_nibble) + 1)

lib/src/trie/proof_decode/tests.rs

@@ -2391,3 +2391,43 @@ fn issue_2035() {
         .collect::<Vec<_>>()
     );
 }
+
+#[test]
+fn issue_2035_bis() {
+    // Repro for the second issue in <https://github.com/smol-dot/smoldot/issues/2035>.
+    let proof = include_bytes!("./issue_2035_bis_proof");
+    let state_root_hash: [u8; 32] = [
+        241, 25, 249, 180, 210, 108, 169, 82, 223, 38, 152, 201, 41, 218, 107, 136, 119, 165, 62,
+        159, 100, 159, 44, 63, 211, 220, 195, 145, 119, 29, 251, 98,
+    ];
+    let key: [u8; 44] = [
+        0x63, 0xf7, 0x8c, 0x98, 0x72, 0x3d, 0xdc, 0x90, 0x73, 0x52, 0x3e, 0xf3, 0xbe, 0xef, 0xda,
+        0x0c, 0xa9, 0x5d, 0xac, 0x46, 0xc0, 0x7a, 0x40, 0xd9, 0x15, 0x06, 0xe7, 0x63, 0x7e, 0xc4,
+        0xba, 0x57, 0x07, 0x1c, 0xef, 0xf5, 0xb0, 0xf6, 0x4d, 0x36, 0x2e, 0x08, 0x00, 0x00,
+    ];
+
+    let decoded = super::decode_and_verify_proof(super::Config { proof }).unwrap();
+
+    let next_key = decoded.next_key(
+        &state_root_hash,
+        trie::bytes_to_nibbles(key.iter().copied()),
+        false,
+        iter::empty(),
+        false,
+    );
+
+    assert_eq!(
+        next_key.unwrap().unwrap().collect::<Vec<_>>(),
+        trie::bytes_to_nibbles(
+            [
+                0x63, 0xf7, 0x8c, 0x98, 0x72, 0x3d, 0xdc, 0x90, 0x73, 0x52, 0x3e, 0xf3, 0xbe, 0xef,
+                0xda, 0x0c, 0xa9, 0x5d, 0xac, 0x46, 0xc0, 0x7a, 0x40, 0xd9, 0x15, 0x06, 0xe7, 0x63,
+                0x7e, 0xc4, 0xba, 0x57, 0x0f, 0x47, 0x4e, 0xe8, 0x5a, 0x3c, 0xd6, 0x22, 0xf8, 0x07,
+                0x00, 0x00
+            ]
+            .iter()
+            .copied()
+        )
+        .collect::<Vec<_>>()
+    );
+}

wasm-node/CHANGELOG.md

@@ -2,6 +2,10 @@
 
 ## Unreleased
 
+### Fixed
+
+- Fix another bug concerning incomplete Merkle proofs, similar to the one fixed in v2.0.32. ([#2039](https://github.com/smol-dot/smoldot/pull/2039))
+
 ## 2.0.32 - 2024-11-08
 
 ### Fixed