fix(tvix/eval): Propagate catchables in NixAttrs::construct

Correctly propagate the case where the *key* of an attrset is a
Value::Catchable (eg { "${builtins.throw "c"}" = "b"; }) in
`NixAttrs::construct`, by converting the return type to
`Result<Result<Self, CatchableErrorKind>, ErrorKind>` (ugh!!) and
correctly handling that everywhere (including an `expect` in the
Deserialize impl for NixAttrs, since afaict this is impossible to hit
when deserializing from stuff like JSON).

Change-Id: Ic4bc611fbfdab27c0bd8a40759689a87c4004a17
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10786
Reviewed-by: raitobezarius <tvl@lahfa.xyz>
Tested-by: BuildkiteCI
This commit is contained in:
Aspen Smith 2024-02-09 12:59:04 -05:00 committed by aspen
parent 7a589b3ec6
commit 3fb0697a71
5 changed files with 31 additions and 13 deletions

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@ -0,0 +1 @@
false

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@ -0,0 +1 @@
(builtins.tryEval { "${builtins.throw "a"}" = "b"; }).success

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@ -19,6 +19,7 @@ use super::thunk::ThunkSet;
use super::TotalDisplay;
use super::Value;
use crate::errors::ErrorKind;
use crate::CatchableErrorKind;
lazy_static! {
static ref NAME_S: NixString = "name".into();
@ -170,7 +171,9 @@ impl<'de> Deserialize<'de> for NixAttrs {
stack_array.push(value);
}
NixAttrs::construct(stack_array.len() / 2, stack_array).map_err(A::Error::custom)
Ok(NixAttrs::construct(stack_array.len() / 2, stack_array)
.map_err(A::Error::custom)?
.expect("Catchable values are unreachable here"))
}
}
@ -333,7 +336,10 @@ impl NixAttrs {
/// Implement construction logic of an attribute set, to encapsulate
/// logic about attribute set optimisations inside of this module.
pub fn construct(count: usize, mut stack_slice: Vec<Value>) -> Result<Self, ErrorKind> {
pub fn construct(
count: usize,
mut stack_slice: Vec<Value>,
) -> Result<Result<Self, CatchableErrorKind>, ErrorKind> {
debug_assert!(
stack_slice.len() == count * 2,
"construct_attrs called with count == {}, but slice.len() == {}",
@ -343,13 +349,13 @@ impl NixAttrs {
// Optimisation: Empty attribute set
if count == 0 {
return Ok(NixAttrs(AttrsRep::Empty));
return Ok(Ok(NixAttrs(AttrsRep::Empty)));
}
// Optimisation: KV pattern
if count == 2 {
if let Some(kv) = attempt_optimise_kv(&mut stack_slice) {
return Ok(kv);
return Ok(Ok(kv));
}
}
@ -369,11 +375,13 @@ impl NixAttrs {
continue;
}
Value::Catchable(err) => return Ok(Err(err)),
other => return Err(ErrorKind::InvalidAttributeName(other)),
}
}
Ok(attrs)
Ok(Ok(attrs))
}
/// Construct an optimized "KV"-style attribute set given the value for the

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@ -4,7 +4,9 @@ use super::*;
#[test]
fn test_empty_attrs() {
let attrs = NixAttrs::construct(0, vec![]).expect("empty attr construction should succeed");
let attrs = NixAttrs::construct(0, vec![])
.expect("empty attr construction should succeed")
.unwrap();
assert!(
matches!(attrs, NixAttrs(AttrsRep::Empty)),
@ -15,7 +17,8 @@ fn test_empty_attrs() {
#[test]
fn test_simple_attrs() {
let attrs = NixAttrs::construct(1, vec![Value::from("key"), Value::from("value")])
.expect("simple attr construction should succeed");
.expect("simple attr construction should succeed")
.unwrap();
assert!(
matches!(attrs, NixAttrs(AttrsRep::Im(_))),
@ -39,7 +42,8 @@ fn test_kv_attrs() {
meaning_val.clone(),
],
)
.expect("constructing K/V pair attrs should succeed");
.expect("constructing K/V pair attrs should succeed")
.unwrap();
match kv_attrs {
NixAttrs(AttrsRep::KV { name, value })
@ -55,7 +59,7 @@ fn test_kv_attrs() {
#[test]
fn test_empty_attrs_iter() {
let attrs = NixAttrs::construct(0, vec![]).unwrap();
let attrs = NixAttrs::construct(0, vec![]).unwrap().unwrap();
assert!(attrs.iter().next().is_none());
}
@ -75,7 +79,8 @@ fn test_kv_attrs_iter() {
meaning_val.clone(),
],
)
.expect("constructing K/V pair attrs should succeed");
.expect("constructing K/V pair attrs should succeed")
.unwrap();
let mut iter = kv_attrs.iter().collect::<Vec<_>>().into_iter();
let (k, v) = iter.next().unwrap();
@ -90,7 +95,8 @@ fn test_kv_attrs_iter() {
#[test]
fn test_map_attrs_iter() {
let attrs = NixAttrs::construct(1, vec![Value::from("key"), Value::from("value")])
.expect("simple attr construction should succeed");
.expect("simple attr construction should succeed")
.unwrap();
let mut iter = attrs.iter().collect::<Vec<_>>().into_iter();
let (k, v) = iter.next().unwrap();

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@ -932,9 +932,11 @@ where
fn run_attrset(&mut self, frame: &CallFrame, count: usize) -> EvalResult<()> {
let attrs = NixAttrs::construct(count, self.stack.split_off(self.stack.len() - count * 2))
.with_span(frame, self)?;
.with_span(frame, self)?
.map(Value::attrs)
.into();
self.stack.push(Value::attrs(attrs));
self.stack.push(attrs);
Ok(())
}