ottyl/tickets/094-adopt-rustfmt.md

094 — Adopt rustfmt and format the codebase

Summary

The Rust backend has no rustfmt.toml and isn't currently formatted to rustfmt's defaults: cargo fmt -- --check exits non-zero, reporting diffs across 24 files (352 diff hunks total).

Where

• No rustfmt.toml / .rustfmt.toml exists at the repo root.
• cargo fmt -- --check reports diffs in src/api/{dto,mcp_server,mod}.rs, src/cli/{mod,sessions}.rs, src/config/{mod,profile}.rs, and most of src/engine/** (alerts.rs, data_value.rs, filter_datetime.rs, filter_parser.rs, ingest.rs, logfmt.rs, message.rs, mod.rs, promql.rs, rate.rs, snapshot/{filter,metrics,mod,params,query,sort}.rs, tests.rs). Heaviest: src/engine/snapshot/mod.rs (~65 hunks), src/config/profile.rs (~38), src/api/mod.rs (~35), src/engine/alerts.rs (~28).
• Makefile:26 (lint-be) currently only runs cargo clippy --all-targets — no cargo fmt --check step.

Scope

• Add a rustfmt.toml if any defaults should be overridden (otherwise an empty/absent file is fine and rustfmt defaults apply — decide whether to keep the file empty for documentation purposes or omit it).
• Run cargo fmt across the whole src/ tree as a single, non-functional formatting commit (don't mix with logic changes, to keep the diff reviewable and git blame-friendly).
• Add a cargo fmt --check step to make lint (or a new make fmt-check wired into CI) so future changes can't drift out of format again.