EpicGames/lore · error

Failed to parse

Error message

Failed to parse

What it means

In the same test, get_metadata::parse_response is applied to the handler's output bytes and .expect('Failed to parse') fires if the response bytes are not a valid get_metadata response. This means the handler produced output that does not match the expected response encoding for the ImmutableLocalGetMetadata operation.

Solutions

1. Confirm parse_response matches the opcode/response type actually produced by run_request_handler
2. Re-run with the handler error surfaced (fix the sibling 'handler should succeed' expect first, if it fires)
3. Verify collapse_bytes is applied to service_output exactly as other passing tests do
4. Update parse_response usage if the response wire format changed

Example fix

// before
let parsed_response = get_metadata::parse_response(collapse_bytes(&service_output)).expect("Failed to parse");
// after
let parsed_response = get_metadata::parse_response(collapse_bytes(&service_output))
    .unwrap_or_else(|e| panic!("Failed to parse get_metadata response: {e:?}"));

fn response_parses(bytes: &[u8]) -> bool { get_metadata::parse_response(bytes.to_vec()).is_ok() }

fn looks_like_metadata_response(bytes: &[u8]) -> bool { !bytes.is_empty() && bytes.len() > header_len(bytes) }

match get_metadata::parse_response(collapse_bytes(&service_output)) {
    Ok(resp) => assert_eq!(resp.match_made, StoreMatch::MatchNone),
    Err(e) => panic!("response shape mismatch: {e:?}"),
}

When it happens

Trigger: The handler returned an error/empty payload (e.g. after a panic upstream), the response framing changed (header/opcode mismatch), or collapse_bytes mangled chunking so parse_response reads malformed bytes.

Common situations: Occurs when protocol chunk encoding is refactored, when the miss path returns a differently shaped response than tests assume, or when the wrong parse function is used for the opcode under test.

Understand the failure class

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

• handler should succeed even for a miss
• Failed to create main store
• Failed to create local store
• put should work
• Failed to write data

AI-assisted analysis of EpicGames/lore@074eb0b0d1 (2026-09-13). Data as JSON: /api/errors/54b929698c37f804. Report an issue: GitHub.

Appendix: source

Thrown at lore-server/src/quic/replication_store_service/server.rs:1059

            .expect("handler failed");
        let parsed_response =
            get_metadata::parse_response(collapse_bytes(&service_output)).expect("Failed to parse");
        assert_eq!(parsed_response.match_made, StoreMatch::MatchFull);

        // Regular ImmutableGetMetadata should NOT find it (main store is empty)
        let parse_output = service
            .parse_request_bytes(
                &CommandHeader::new(Command::ImmutableGetMetadata as QuicOpCode, 0, 0),
                collapse_bytes_without_header(&request.to_quic_chunks()),
            )
            .expect("Failed to parse");

        let service_output = service
            .run_request_handler(AttributeMap::default().into(), parse_output)
            .await
            .expect("handler should succeed even for a miss");
        let parsed_response =
            get_metadata::parse_response(collapse_bytes(&service_output)).expect("Failed to parse");
        assert_eq!(parsed_response.match_made, StoreMatch::MatchNone);
    }

    /// Helper to create a second independent store for local-store routing tests
    async fn create_two_stores() -> (
        Arc<dyn ImmutableStore>,
        Arc<dyn ImmutableStore>,
        Arc<lore_revision::interface::ExecutionContext>,
    ) {
        let (main_store, _, execution) = test_store_create()
            .await
            .expect("Failed to create main store");
        let (local_store, _, _) = test_store_create()
            .await
            .expect("Failed to create local store");
        (main_store, local_store, execution)
    }

View on GitHub (pinned to 074eb0b0d1)