salsa/tests/panic_safely.rs
Niko Matsakis fad97eeb6a remove the DB parameter
This had two unexpected consequences, one unfortunate, one "medium":

* All `salsa::Database` must be `'static`. This falls out from
`Q::DynDb` not having access to any lifetimes, but also the defaulting
rules for `dyn QueryGroup` that make it `dyn QueryGroup + 'static`. We
don't really support generic databases anyway yet so this isn't a big
deal, and we can add workarounds later (ideally via GATs).

* It is now statically impossible to invoke `snapshot` from a query,
and so we don't need to test that it panics. This is because the
signature of `snapshot` returns a `Snapshot<Self>` and that is not
accessible to a `dyn QueryGroup` type. Similarly, invoking
`Runtime::snapshot` directly is not possible becaues it is
crate-private. So I removed the test. This seems ok, but eventually I
would like to expose ways for queries to do parallel
execution (matklad and I had talked about a "speculation" primitive
for enabling that).

* This commit is 99% boilerplate I did with search-and-replace. I also
rolled in a few other changes I might have preferred to factor out,
most notably removing the `GetQueryTable` plumbing trait in favor of
free-methods, but it was awkward to factor them out and get all the
generics right (so much simpler in this version).
2020-07-04 14:17:11 +00:00

95 lines
2.5 KiB
Rust

use salsa::{Database, ParallelDatabase, Snapshot};
use std::panic::{self, AssertUnwindSafe};
use std::sync::atomic::{AtomicU32, Ordering::SeqCst};
#[salsa::query_group(PanicSafelyStruct)]
trait PanicSafelyDatabase: salsa::Database {
#[salsa::input]
fn one(&self) -> usize;
fn panic_safely(&self) -> ();
fn outer(&self) -> ();
}
fn panic_safely(db: &dyn PanicSafelyDatabase) -> () {
assert_eq!(db.one(), 1);
}
static OUTER_CALLS: AtomicU32 = AtomicU32::new(0);
fn outer(db: &dyn PanicSafelyDatabase) -> () {
OUTER_CALLS.fetch_add(1, SeqCst);
db.panic_safely();
}
#[salsa::database(PanicSafelyStruct)]
#[derive(Default)]
struct DatabaseStruct {
storage: salsa::Storage<Self>,
}
impl salsa::Database for DatabaseStruct {}
impl salsa::ParallelDatabase for DatabaseStruct {
fn snapshot(&self) -> Snapshot<Self> {
Snapshot::new(DatabaseStruct {
storage: self.storage.snapshot(),
})
}
}
#[test]
fn should_panic_safely() {
let mut db = DatabaseStruct::default();
db.set_one(0);
// Invoke `db.panic_safely() without having set `db.one`. `db.one` will
// return 0 and we should catch the panic.
let result = panic::catch_unwind(AssertUnwindSafe({
let db = db.snapshot();
move || db.panic_safely()
}));
assert!(result.is_err());
// Set `db.one` to 1 and assert ok
db.set_one(1);
let result = panic::catch_unwind(AssertUnwindSafe(|| db.panic_safely()));
assert!(result.is_ok());
// Check, that memoized outer is not invalidated by a panic
{
assert_eq!(OUTER_CALLS.load(SeqCst), 0);
db.outer();
assert_eq!(OUTER_CALLS.load(SeqCst), 1);
db.set_one(0);
let result = panic::catch_unwind(AssertUnwindSafe(|| db.outer()));
assert!(result.is_err());
assert_eq!(OUTER_CALLS.load(SeqCst), 1);
db.set_one(1);
db.outer();
assert_eq!(OUTER_CALLS.load(SeqCst), 1);
}
}
#[test]
fn storages_are_unwind_safe() {
fn check_unwind_safe<T: std::panic::UnwindSafe>() {}
check_unwind_safe::<&DatabaseStruct>();
}
#[test]
fn panics_clear_query_stack() {
let db = DatabaseStruct::default();
// Invoke `db.panic_if_not_one() without having set `db.input`. `db.input`
// will default to 0 and we should catch the panic.
let result = panic::catch_unwind(AssertUnwindSafe(|| db.panic_safely()));
assert!(result.is_err());
// The database has been poisoned and any attempt to increment the
// revision should panic.
assert_eq!(db.salsa_runtime().active_query(), None);
}