linera-io/linera-protocol

Parent tracker: #6107 Summary Introduce madsim (Rust async runtime with deterministic simulation, drop-in tokio-compatible) to linera-core's test harness. Start with one representative test, validate determinism, expand module-by-module. Motivation Several recent bug classes would have been catchable — and reproducible via seed replay — under deterministic simulation testing (DST): The cluster of correctness fixes following the #5790 chain-actors refactor: cancellation safety (#6056 merged; #6051 closed and superseded), Arc lifecycle in storage cache (#6046), save-failure handling (#6053), load-failure handling (#6015). The 2026-04-12 Conway incident combining TTL inversion (#5991) with silent OTLP queue drops. The cross-chain mpsc-loss issue on pod kill (see investigation-cross-chain-crash-safety.md). multileader-stuck-round consensus stall. Shared shape: a race / cancellation / ordering pattern reachable only under specific scheduling that normal tokio tests rarely produce. DST

Parent: #5977 (Tier 1 item 4) Problem The colored crate is used to emit ANSI escape codes in the linera CLI output. Two concrete issues: ANSI codes leak to stdout in net up (linera-service/src/cli/net_up_utils.rs:311-330). The command prints shell export statements wrapped in .bold(), which emit ANSI escape codes when rendered. Stdout should always be clean text suitable for parsing or piping — never formatted. NO_COLOR / CLICOLOR environment variables are not explicitly honored. The colored crate auto-detects TTY but its behavior when piped is not guaranteed to produce clean output, and there's no documented environment override. Relevant existing usages: linera-service/src/cli/net_up_utils.rs:6 — use colored::Colorize as _; linera-service/src/cli/net_up_utils.rs:317,325,329 — .bold() calls on stdout println!s for export LINERA_WALLET=... etc. linera-service/src/cli/main.rs:36 — use colored::Colorize; linera-service/src/cli/main.rs:1473 — info!("{}", "Application created

Parent: #5977 (Tier 1 item 3) Problem Three CLI commands print Rust Debug format output, which: Uses Rust struct syntax (Foo { field: "value" }), not a standard data format. Is inconsistent with the rest of the CLI, which uses Display or serde_json::to_string_pretty. Is harder for scripts and agents to parse reliably than JSON or plain text. Changes shape across Rust versions (not technically stable). Affected lines All in linera-service/src/cli/main.rs: Line 1393 — ListEventsFromIndex: println!("{:#?}", index_events); Line 1751 — Chain(ChainCommand::ShowBlock { .. }): println!("{:#?}", block); Line 1768 — Chain(ChainCommand::ShowChainDescription { .. }): println!("{:#?}", description); Proposed fix Replace with serde_json::to_string_pretty. Both underlying types already derive Serialize: ConfirmedBlock at linera-chain/src/block.rs:80 (#[derive(Debug, PartialEq, Eq, Clone, Serialize, Deserialize, Allocative)]) ChainDescription at linera-base/src/data_types.rs:890 (#[deriv

We use integers as keys in many places (procotol and examples) but usually without a custom key serialization. As a result, graphql queries show keys ordered by little-endian bytes. See AskPrice and BidPrice in the matching engine example.