feat: experimental Turso Database engine backend (litewire-turso)

Cargo.toml

@@ -8,6 +8,7 @@ members = [
     "crates/litewire-postgres",
     "crates/litewire-tds",
     "crates/litewire-hrana",
+    "crates/litewire-turso",
 ]
 
 [workspace.package]
@@ -24,6 +25,7 @@ litewire-mysql = { path = "crates/litewire-mysql" }
 litewire-postgres = { path = "crates/litewire-postgres" }
 litewire-tds = { path = "crates/litewire-tds" }
 litewire-hrana = { path = "crates/litewire-hrana" }
+litewire-turso = { path = "crates/litewire-turso" }
 
 # Async runtime
 tokio = { version = "1", features = ["full"] }
@@ -39,6 +41,11 @@ sqlparser = { version = "0.57", features = ["serde"] }
 # to fill in `Column.decltype` on empty result sets (an unexecuted prepared
 # SELECT). Without it, wire-frontend type inference has to LIMIT-0 probe.
 rusqlite = { version = "0.32", features = ["bundled", "column_decltype"] }
+# Turso Database — the ground-up Rust rewrite of SQLite
+# (github.com/tursodatabase/turso). Pinned exactly: the engine is Beta and
+# API/behavior move between releases. 0.7.0 is the first non-pre release on
+# the 0.7 line (July 2026). Bump deliberately, never via `cargo update`.
+turso = { version = "=0.7.0", default-features = false }
 
 # HTTP (Hrana)
 axum = "0.8"

README.md

@@ -88,6 +88,7 @@ async fn main() -> anyhow::Result<()> {
 |---------|-------------|----------|
 | `Rusqlite` | `backend-rusqlite` | Direct in-process SQLite |
 | `HranaClient` | `backend-hrana-client` | Remote SQLite via the Hrana HTTP protocol (sqld / Turso) |
+| `Turso` | `turso` | **Experimental** — [Turso Database](https://github.com/tursodatabase/turso) engine (Rust rewrite of SQLite, Beta upstream; pinned `=0.7.0`). See `crates/litewire-turso` docs for limitations (no `VACUUM`, no multi-process access) |
 | Custom | implement `Backend` trait | Bring your own |
 
 The `HranaClient` backend connects to [sqld](https://github.com/tursodatabase/libsql) via HTTP, enabling embedded replicas and distributed SQLite clusters.

crates/litewire-turso/Cargo.toml

@@ -0,0 +1,22 @@
+[package]
+name = "litewire-turso"
+description = "Experimental Turso Database (Rust SQLite rewrite) backend for litewire"
+version.workspace = true
+edition.workspace = true
+rust-version.workspace = true
+license.workspace = true
+
+[dependencies]
+# Path dep (not workspace) so default features can be disabled: the trait
+# is all this crate needs at runtime; rusqlite stays out of the build.
+litewire-backend = { path = "../litewire-backend", version = "0.1.0", default-features = false }
+async-trait = { workspace = true }
+tokio = { workspace = true }
+tracing = { workspace = true }
+turso = { workspace = true }
+
+[dev-dependencies]
+# rusqlite backend enabled for tests/examples only: the Phase 1 gate
+# harness (examples/phase1_gates.rs) compares both engines side by side.
+litewire-backend = { workspace = true, features = ["rusqlite"] }
+tokio = { workspace = true, features = ["full"] }