mirror of
https://github.com/salsa-rs/salsa.git
synced 2025-01-14 17:18:20 +00:00
5b8412656c
Requires unsafe, since Rust currently doesn't have built-in support for guaranteed in-place initialization. Unfortunately, this unsafety propagates to making `Jar` unsafe to implement in order to guarantee that the jar is initialized, but since the preferred way to implement it is via `salsa::jar`, this won't impact most users.
35 lines
790 B
Rust
35 lines
790 B
Rust
//! Tests that we can create a database of only 0-size jars without invoking UB
|
|
|
|
use salsa::storage::HasJars;
|
|
|
|
#[salsa::jar(db = Db)]
|
|
struct Jar();
|
|
|
|
trait Db: salsa::DbWithJar<Jar> {}
|
|
|
|
#[salsa::db(Jar)]
|
|
#[derive(Default)]
|
|
struct Database {
|
|
storage: salsa::Storage<Self>,
|
|
}
|
|
|
|
impl salsa::Database for Database {}
|
|
|
|
impl Db for Database {}
|
|
|
|
#[test]
|
|
fn execute() {
|
|
let db = Database::default();
|
|
let jars = db.storage.jars().0;
|
|
|
|
ensure_init(jars);
|
|
}
|
|
|
|
fn ensure_init(place: *const <Database as HasJars>::Jars) {
|
|
use std::mem::forget;
|
|
use std::ptr::addr_of;
|
|
|
|
// SAFETY: Intentionally tries to access potentially uninitialized memory,
|
|
// so that miri can catch if we accidentally forget to initialize the memory.
|
|
forget(unsafe { addr_of!((*place).0).read() });
|
|
}
|