feat: support borrowed parameter types via borrowed_rs_type override

Cargo.toml

@@ -36,7 +36,7 @@ proc-macro2 = "1"
 quote = "1"
 serde = { version = "1", features = ["derive"] }
 serde_json = { workspace = true }
-syn = { version = "2", features = ["full"] }
+syn = { version = "2", features = ["full", "visit-mut"] }
 
 [dev-dependencies]
 insta = { version = "1", features = ["filters"] }

README.md

@@ -56,7 +56,7 @@ All options are passed in `codegen[*].options`:
 | Key | Type | Default | Description |
 |---|---|---|---|
 | `output` | string | `queries.rs` | Output filename |
-| `overrides` | array | `[]` | Type overrides (see below) |
+| `overrides` | array | `[]` | Type overrides (`rs_type`, optional `borrowed_rs_type`; see below) |
 | `row_derives` | array | `[]` | Extra derives for row and params structs |
 | `enum_derives` | array | `[]` | Extra derives for generated enum types |
 | `composite_derives` | array | `[]` | Extra derives for generated composite types |
@@ -77,6 +77,55 @@ options:
       copy_cheap: false
 ```
 
+### Borrowed parameters
+
+Add `borrowed_rs_type` to a type or column override to take that type by
+reference in parameter positions. Row struct fields, array contents, and the
+`Item` of `:copyfrom` chunks continue to use the owned form:
+
+```yaml
+options:
+  overrides:
+    - db_type: "text"
+      borrowed_rs_type: "&str"
+```
+
+With that override, generated signatures borrow scalar `text` parameters and
+the codegen threads lifetimes only where needed:
+
+```rust
+// Scalar — lifetime elided
+pub async fn get_author_by_name<E: AsExecutor>(
+    mut db: E, name: &str,
+) -> Result<GetAuthorByNameRow, sqlx::Error> { ... }
+
+// Multiple params — struct carries `'a`, fn uses `'_`
+pub struct CreateAuthorParams<'a> {
+    pub name: &'a str,
+    pub bio: Option<&'a str>,
+}
+pub async fn create_author<E: AsExecutor>(
+    mut db: E, arg: CreateAuthorParams<'_>,
+) -> Result<CreateAuthorRow, sqlx::Error> { ... }
+
+// Row struct stays owned — results are returned by value
+pub struct GetAuthorByNameRow { pub name: String, /* ... */ }
+```
+
+`rs_type` is optional alongside `borrowed_rs_type`. Omit it to keep the
+built-in owned default; set both to fully customize:
+
+```yaml
+overrides:
+  - db_type: "text"
+    rs_type: "MyStr"           # used for row fields & array contents
+    borrowed_rs_type: "&MyStr" # used for scalar params
+```
+
+For `text[]` and `sqlc.slice(text)` the wrapper becomes a borrowed slice while
+the inner item stays owned (`&[String]`), so callers can pass `&my_vec`
+directly without re-collecting.
+
 ## Supported PostgreSQL types
 
 | PostgreSQL | Rust |

examples/advanced-types/src/queries.rs

@@ -1,4 +1,4 @@
-// Code generated by sqlc-gen-sqlx v0.1.7. DO NOT EDIT.
+// Code generated by sqlc-gen-sqlx v0.2.0. DO NOT EDIT.
 // sqlc version: v1.30.0
 
 #![allow(

examples/basic/src/queries.rs

@@ -1,4 +1,4 @@
-// Code generated by sqlc-gen-sqlx v0.1.7. DO NOT EDIT.
+// Code generated by sqlc-gen-sqlx v0.2.0. DO NOT EDIT.
 // sqlc version: v1.30.0
 
 #![allow(

examples/batch/src/queries.rs

@@ -1,4 +1,4 @@
-// Code generated by sqlc-gen-sqlx v0.1.7. DO NOT EDIT.
+// Code generated by sqlc-gen-sqlx v0.2.0. DO NOT EDIT.
 // sqlc version: v1.30.0
 
 #![allow(

examples/borrowed/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "borrowed"
+version = "0.1.0"
+edition = "2024"
+
+[dependencies]
+sqlx = { workspace = true }
+tokio = { workspace = true }

examples/borrowed/queries.sql

@@ -0,0 +1,14 @@
+-- name: GetAuthor :one
+SELECT id, name, bio FROM authors WHERE id = $1;
+
+-- name: GetAuthorByName :one
+SELECT id, name, bio FROM authors WHERE name = $1;
+
+-- name: ListAuthors :many
+SELECT id, name, bio FROM authors ORDER BY name;
+
+-- name: CreateAuthor :one
+INSERT INTO authors (name, bio) VALUES ($1, $2) RETURNING id, name, bio;
+
+-- name: DeleteAuthor :exec
+DELETE FROM authors WHERE id = $1;

examples/borrowed/schema.sql

@@ -0,0 +1,5 @@
+CREATE TABLE authors (
+    id   BIGSERIAL PRIMARY KEY,
+    name TEXT      NOT NULL,
+    bio  TEXT
+);

examples/borrowed/src/main.rs

@@ -0,0 +1,51 @@
+#[cfg(test)]
+use sqlx::{Connection as _, PgConnection};
+
+#[path = "queries.rs"]
+#[cfg(test)]
+mod queries;
+#[cfg(test)]
+use queries::CreateAuthorParams;
+
+#[cfg(test)]
+#[tokio::test]
+async fn test_borrowed_author_roundtrip() {
+    let db_url = std::env::var("DATABASE_URL")
+        .unwrap_or_else(|_| "postgres://sqlc:sqlc@localhost:5432/sqlc_test".to_string());
+    let mut conn = PgConnection::connect(&db_url).await.expect("connect");
+
+    sqlx::query("CREATE TABLE IF NOT EXISTS authors (id BIGSERIAL PRIMARY KEY, name TEXT NOT NULL, bio TEXT)")
+        .execute(&mut conn)
+        .await
+        .unwrap();
+    sqlx::query("TRUNCATE authors RESTART IDENTITY CASCADE")
+        .execute(&mut conn)
+        .await
+        .unwrap();
+
+    // Borrow string literals directly — no allocation needed.
+    let author = queries::create_author(
+        &mut conn,
+        CreateAuthorParams {
+            name: "Alice",
+            bio: Some("Loves Rust"),
+        },
+    )
+    .await
+    .expect("create");
+    assert_eq!(author.name, "Alice");
+    assert_eq!(author.bio.as_deref(), Some("Loves Rust"));
+
+    // Borrow an owned String the caller already has.
+    let stored_name: String = author.name.clone();
+    let fetched = queries::get_author_by_name(&mut conn, &stored_name)
+        .await
+        .expect("get_by_name");
+    assert_eq!(fetched.id, author.id);
+
+    queries::delete_author(&mut conn, author.id)
+        .await
+        .expect("delete");
+}
+
+fn main() {}

examples/borrowed/src/queries.rs

@@ -0,0 +1,113 @@
+// Code generated by sqlc-gen-sqlx v0.2.0. DO NOT EDIT.
+// sqlc version: v1.30.0
+
+#![allow(
+    dead_code,
+    reason = "generated queries may expose items a caller does not use"
+)]
+
+pub trait AsExecutor {
+    fn as_executor(&mut self) -> impl sqlx::Executor<'_, Database = sqlx::Postgres>;
+}
+impl AsExecutor for sqlx::PgPool {
+    fn as_executor(&mut self) -> impl sqlx::Executor<'_, Database = sqlx::Postgres> {
+        &*self
+    }
+}
+impl AsExecutor for &sqlx::PgPool {
+    fn as_executor(&mut self) -> impl sqlx::Executor<'_, Database = sqlx::Postgres> {
+        *self
+    }
+}
+impl AsExecutor for sqlx::PgConnection {
+    fn as_executor(&mut self) -> impl sqlx::Executor<'_, Database = sqlx::Postgres> {
+        &mut *self
+    }
+}
+impl AsExecutor for sqlx::Transaction<'_, sqlx::Postgres> {
+    fn as_executor(&mut self) -> impl sqlx::Executor<'_, Database = sqlx::Postgres> {
+        &mut **self
+    }
+}
+impl AsExecutor for sqlx::pool::PoolConnection<sqlx::Postgres> {
+    fn as_executor(&mut self) -> impl sqlx::Executor<'_, Database = sqlx::Postgres> {
+        &mut **self
+    }
+}
+impl<T: AsExecutor + ?Sized> AsExecutor for &mut T {
+    fn as_executor(&mut self) -> impl sqlx::Executor<'_, Database = sqlx::Postgres> {
+        (**self).as_executor()
+    }
+}
+const GET_AUTHOR: &str = "SELECT id, name, bio FROM authors WHERE id = $1";
+#[derive(Debug, Clone, sqlx::FromRow)]
+pub struct GetAuthorRow {
+    pub id: i64,
+    pub name: String,
+    pub bio: Option<String>,
+}
+pub async fn get_author<E: AsExecutor>(mut db: E, id: i64) -> Result<GetAuthorRow, sqlx::Error> {
+    sqlx::query_as::<_, GetAuthorRow>(GET_AUTHOR)
+        .bind(id)
+        .fetch_one(db.as_executor())
+        .await
+}
+const GET_AUTHOR_BY_NAME: &str = "SELECT id, name, bio FROM authors WHERE name = $1";
+#[derive(Debug, Clone, sqlx::FromRow)]
+pub struct GetAuthorByNameRow {
+    pub id: i64,
+    pub name: String,
+    pub bio: Option<String>,
+}
+pub async fn get_author_by_name<E: AsExecutor>(
+    mut db: E,
+    name: &str,
+) -> Result<GetAuthorByNameRow, sqlx::Error> {
+    sqlx::query_as::<_, GetAuthorByNameRow>(GET_AUTHOR_BY_NAME)
+        .bind(name)
+        .fetch_one(db.as_executor())
+        .await
+}
+const LIST_AUTHORS: &str = "SELECT id, name, bio FROM authors ORDER BY name";
+#[derive(Debug, Clone, sqlx::FromRow)]
+pub struct ListAuthorsRow {
+    pub id: i64,
+    pub name: String,
+    pub bio: Option<String>,
+}
+pub async fn list_authors<E: AsExecutor>(mut db: E) -> Result<Vec<ListAuthorsRow>, sqlx::Error> {
+    sqlx::query_as::<_, ListAuthorsRow>(LIST_AUTHORS)
+        .fetch_all(db.as_executor())
+        .await
+}
+#[derive(Debug, Clone)]
+pub struct CreateAuthorParams<'a> {
+    pub name: &'a str,
+    pub bio: Option<&'a str>,
+}
+const CREATE_AUTHOR: &str =
+    "INSERT INTO authors (name, bio) VALUES ($1, $2) RETURNING id, name, bio";
+#[derive(Debug, Clone, sqlx::FromRow)]
+pub struct CreateAuthorRow {
+    pub id: i64,
+    pub name: String,
+    pub bio: Option<String>,
+}
+pub async fn create_author<E: AsExecutor>(
+    mut db: E,
+    arg: CreateAuthorParams<'_>,
+) -> Result<CreateAuthorRow, sqlx::Error> {
+    sqlx::query_as::<_, CreateAuthorRow>(CREATE_AUTHOR)
+        .bind(arg.name)
+        .bind(arg.bio)
+        .fetch_one(db.as_executor())
+        .await
+}
+const DELETE_AUTHOR: &str = "DELETE FROM authors WHERE id = $1";
+pub async fn delete_author<E: AsExecutor>(mut db: E, id: i64) -> Result<(), sqlx::Error> {
+    sqlx::query(DELETE_AUTHOR)
+        .bind(id)
+        .execute(db.as_executor())
+        .await?;
+    Ok(())
+}

examples/enums/src/queries.rs

@@ -1,4 +1,4 @@
-// Code generated by sqlc-gen-sqlx v0.1.7. DO NOT EDIT.
+// Code generated by sqlc-gen-sqlx v0.2.0. DO NOT EDIT.
 // sqlc version: v1.30.0
 
 #![allow(

sqlc.yaml

@@ -3,7 +3,7 @@ plugins:
   - name: sqlc-gen-sqlx
     wasm:
       url: file://target/wasm32-wasip1/debug/sqlc-gen-sqlx.wasm
-      sha256: "87780a1e4ebe3f7bfb3fdd4041e8f7127b5c35d540c40b456558d87f1ef62e5b"
+      sha256: "0405bc13685568ff34c6ff8fb43fc4fe474916b1175007c31b2485c99a6ee2a7"
 
 sql:
   - schema: examples/basic/schema.sql
@@ -41,3 +41,15 @@ sql:
         out: examples/enums/src
         options:
           output: queries.rs
+
+  - schema: examples/borrowed/schema.sql
+    queries: examples/borrowed/queries.sql
+    engine: postgresql
+    codegen:
+      - plugin: sqlc-gen-sqlx
+        out: examples/borrowed/src
+        options:
+          output: queries.rs
+          overrides:
+            - db_type: "text"
+              borrowed_rs_type: "&str"