v0.3.0

This release aggregates a coordinated set of breaking and additive API changes that landed across four PRs during the v0.3.0 bundle window. See MIGRATING-0.3.md for complete migration recipes covering every change.

⚠ BREAKING CHANGES

• Flat Error enum. The public hyperdb_api::Error is now a flat canonical structure per the Microsoft Pragmatic Rust Guidelines — no Box<dyn StdError> cause channel, no kind() method, no Other catch-all variant. Error::new and Error::with_cause are deleted in favor of domain-specific snake_case constructors (Error::connection, Error::server, Error::conversion, etc.). The ErrorKind re-export from hyperdb_api is removed. (#70, #71)
• Transaction API consolidation. Connection::begin_transaction / commit / rollback (and the async equivalents) are deprecated and #[doc(hidden)]. Use the RAII guard at Connection::transaction() / AsyncConnection::transaction() instead. (#69, #73)
• FromRow modernization. FromRow::from_row(&Row) becomes FromRow::from_row(RowAccessor<'_>). The blanket 1/2/3/4-tuple FromRow impls are deleted — define a struct with #[derive(FromRow)] instead. New RowAccessor carries a per-query cached column-name → index lookup; new Row::get_by_name for one-off named access. (#61, #62, #74)
• Structured SQLSTATE on Cancelled / Closed / Connection. Error::Cancelled and Error::Closed change from tuple to struct variants carrying sqlstate: Option<String>. Error::Connection gains the same field. Error::sqlstate() now returns Some(...) for these variants when the server provided a code (previously Server-only). New Error::InvalidOperation variant separates caller-API misuse from library invariant violations. (#76)

Features

• #[derive(FromRow)] proc-macro with #[hyperdb(rename = "...")] and #[hyperdb(index = N)] attributes, lives in the new re-exported hyperdb-api-derive crate (#74)
• RowAccessor accessors: get / get_opt (name-based) and position / position_opt (index-based) (#74)
• Ergonomic snake_case constructors workspace-wide for every error variant — &str, String, format!(...) accepted without .to_string() ceremony (#71)
• Typed io::Error sources preserved on HyperProcess lifecycle errors (#76)
• stabilize v0.3.0 public API bundle (#77) (ac39b2c)

Deferred

• Internal client::Error flatten — deferred to v0.3.x as #75 (internal type, zero external consumers; scope grew on second look).

What's Changed

• fix(ci): install mold in release.yml verify job by @StefanSteiner in #58
• chore(api): flatten Error enum and add ergonomic constructors workspace-wide (#70) by @StefanSteiner in #71
• chore(api): deprecate raw transaction trio; migrate MCP async paths to RAII (#69) by @StefanSteiner in #73
• chore(api): modernize FromRow with #[derive] + RowAccessor (#61, #62) by @StefanSteiner in #74
• chore(api): v0.3.0 follow-ups (A: typed I/O sources, B: InvalidOperation, C: structured SQLSTATE) by @StefanSteiner in #76
• feat: stabilize v0.3.0 public API bundle by @StefanSteiner in #77
• chore: enable bump-minor-pre-major for pre-1.0 releases by @StefanSteiner in #79
• chore: release main by @StefanSteiner in #80

Full Changelog: v0.2.3...v0.3.0