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Add a recursion limit to background evaluation #1878
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core/src/eval/mod.rs
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pub fn eval_permissive(&mut self, rt: RichTerm) -> Vec<EvalError> { | ||
/// - We support a recursion limit, to limit the number of times we recurse into | ||
/// arrays or records. | ||
pub fn eval_permissive(&mut self, rt: RichTerm, recursion_limit: u64) -> Vec<EvalError> { |
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Nitpick: should we use usize
instead of u64
? I guess in practice u16
is already amply sufficient, but you might prefer to use a word-aligned value. Using u64
sounds like we need the guarantee to have larger values than u32::MAX
.
core/src/eval/mod.rs
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@@ -966,7 +969,9 @@ impl<R: ImportResolver, C: Cache> VirtualMachine<R, C> { | |||
attrs.pending_contracts.iter().cloned(), | |||
t.pos, | |||
); | |||
inner(slf, acc, value_with_ctr); | |||
if let Some(r) = recursion_limit.checked_sub(1) { |
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nitpick: if we test at the very beginning of the function that recursion_limit > 0
(and return immediatly instead), we have to perform the check only once, instead of at each call site (using saturating sub instead of checked_sub)
Adds a recursion limit (currently hardcoded to 128) to the background evaluator in nls. This limit applies to recursion in arrays or records, not to recursive function calls.
This might fix #1875 (it's hard to tell, as I can't reproduce it). But independent of that, it avoids a crash and preserves eval diagnostics.