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Merged
zharinov merged 1 commit into from
Dec 3, 2025
Merged

feat: Use debug_fuel in release mode #19

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45 changes: 11 additions & 34 deletions crates/plotnik-lib/src/ast/parser/core.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -16,9 +16,6 @@ use crate::ast::lexer::{Token, token_text};
use crate::ast::syntax_kind::token_sets::ROOT_EXPR_FIRST;
use crate::ast::syntax_kind::{SyntaxKind, TokenSet};

#[cfg(debug_assertions)]
const DEFAULT_DEBUG_FUEL: u32 = 256;

const DEFAULT_EXEC_FUEL: u32 = 1_000_000;
const DEFAULT_RECURSION_FUEL: u32 = 512;

Expand Down Expand Up @@ -63,11 +60,8 @@ pub struct Parser<'src> {
pub(super) delimiter_stack: Vec<OpenDelimiter>,

// Fuel limits
/// Debug-only: loop detection fuel. Resets on bump(). Panics when exhausted.
#[cfg(debug_assertions)]
/// Loop detection fuel. Resets on bump(). Panics when exhausted.
pub(super) debug_fuel: std::cell::Cell<u32>,
#[cfg(debug_assertions)]
pub(super) debug_fuel_limit: Option<u32>,

/// Execution fuel. Never replenishes.
exec_fuel_remaining: Option<u32>,
Expand All @@ -91,24 +85,13 @@ impl<'src> Parser<'src> {
depth: 0,
last_error_pos: None,
delimiter_stack: Vec::with_capacity(8),
#[cfg(debug_assertions)]
debug_fuel: std::cell::Cell::new(DEFAULT_DEBUG_FUEL),
#[cfg(debug_assertions)]
debug_fuel_limit: Some(DEFAULT_DEBUG_FUEL),
debug_fuel: std::cell::Cell::new(256),
exec_fuel_remaining: Some(DEFAULT_EXEC_FUEL),
recursion_fuel_limit: Some(DEFAULT_RECURSION_FUEL),
fatal_error: None,
}
}

/// Set debug fuel limit (debug builds only). None = infinite.
#[cfg(debug_assertions)]
pub fn with_debug_fuel(mut self, limit: Option<u32>) -> Self {
self.debug_fuel_limit = limit;
self.debug_fuel.set(limit.unwrap_or(u32::MAX));
self
}

/// Set execution fuel limit. None = infinite.
pub fn with_exec_fuel(mut self, limit: Option<u32>) -> Self {
self.exec_fuel_remaining = limit;
Expand Down Expand Up @@ -142,15 +125,13 @@ impl<'src> Parser<'src> {
self.nth(0)
}

fn reset_debug_fuel(&self) {
self.debug_fuel.set(256);
}

/// Lookahead by `n` tokens (0 = current). Consumes debug fuel (panics if stuck).
pub(super) fn nth(&self, lookahead: usize) -> SyntaxKind {
#[cfg(debug_assertions)]
{
self.assert_progress();
if self.debug_fuel_limit.is_some() {
self.debug_fuel.set(self.debug_fuel.get() - 1);
}
}
self.ensure_progress();

self.tokens
.get(self.pos + lookahead)
Expand Down Expand Up @@ -266,10 +247,7 @@ impl<'src> Parser<'src> {
pub(super) fn bump(&mut self) {
assert!(!self.eof(), "bump called at EOF");

#[cfg(debug_assertions)]
if let Some(limit) = self.debug_fuel_limit {
self.debug_fuel.set(limit);
}
self.reset_debug_fuel();

self.consume_exec_fuel();

Expand All @@ -283,10 +261,7 @@ impl<'src> Parser<'src> {
pub(super) fn skip_token(&mut self) {
assert!(!self.eof(), "skip_token called at EOF");

#[cfg(debug_assertions)]
if let Some(limit) = self.debug_fuel_limit {
self.debug_fuel.set(limit);
}
self.reset_debug_fuel();

self.consume_exec_fuel();

Expand Down Expand Up @@ -398,11 +373,13 @@ impl<'src> Parser<'src> {
return false;
}
self.depth += 1;
self.reset_debug_fuel();
true
}

pub(super) fn exit_recursion(&mut self) {
self.depth = self.depth.saturating_sub(1);
self.reset_debug_fuel();
}

/// Push an opening delimiter onto the stack for tracking unclosed constructs.
Expand Down
14 changes: 6 additions & 8 deletions crates/plotnik-lib/src/ast/parser/invariants.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -7,14 +7,12 @@ use crate::ast::syntax_kind::SyntaxKind;

impl Parser<'_> {
#[inline]
#[cfg(debug_assertions)]
pub(super) fn assert_progress(&self) {
if let Some(limit) = self.debug_fuel_limit {
assert!(
self.debug_fuel.get() != 0,
"parser is stuck: no progress made in {limit} iterations"
);
}
pub(super) fn ensure_progress(&self) {
assert!(
self.debug_fuel.get() != 0,
"parser is stuck: too many lookaheads"
);
self.debug_fuel.set(self.debug_fuel.get() - 1);
}

#[inline]
Expand Down
6 changes: 3 additions & 3 deletions crates/plotnik-lib/src/ast/parser/tests/recovery/coverage.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -330,7 +330,7 @@ fn deeply_nested_trees_hit_recursion_limit() {
input.push(')');
}

let result = Query::builder(&input).with_debug_fuel(None).build();
let result = Query::builder(&input).build();

assert!(
matches!(result, Err(crate::Error::RecursionLimitExceeded)),
Expand All @@ -351,7 +351,7 @@ fn deeply_nested_sequences_hit_recursion_limit() {
input.push('}');
}

let result = Query::builder(&input).with_debug_fuel(None).build();
let result = Query::builder(&input).build();

assert!(
matches!(result, Err(crate::Error::RecursionLimitExceeded)),
Expand All @@ -372,7 +372,7 @@ fn deeply_nested_alternations_hit_recursion_limit() {
input.push(']');
}

let result = Query::builder(&input).with_debug_fuel(None).build();
let result = Query::builder(&input).build();

assert!(
matches!(result, Err(crate::Error::RecursionLimitExceeded)),
Expand Down
19 changes: 0 additions & 19 deletions crates/plotnik-lib/src/query/mod.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -26,8 +26,6 @@ use shape_cardinalities::ShapeCardinality;
/// Builder for configuring and creating a [`Query`].
pub struct QueryBuilder<'a> {
source: &'a str,
#[cfg(debug_assertions)]
debug_fuel: Option<Option<u32>>,
exec_fuel: Option<Option<u32>>,
recursion_fuel: Option<Option<u32>>,
}
Expand All @@ -37,23 +35,11 @@ impl<'a> QueryBuilder<'a> {
pub fn new(source: &'a str) -> Self {
Self {
source,
#[cfg(debug_assertions)]
debug_fuel: None,
exec_fuel: None,
recursion_fuel: None,
}
}

/// Set debug fuel limit (debug builds only). None = infinite.
///
/// Debug fuel resets on each token consumed. It detects parser bugs
/// where no progress is made. Panics when exhausted.
#[cfg(debug_assertions)]
pub fn with_debug_fuel(mut self, limit: Option<u32>) -> Self {
self.debug_fuel = Some(limit);
self
}

/// Set execution fuel limit. None = infinite.
///
/// Execution fuel never replenishes. It protects against large inputs.
Expand All @@ -79,11 +65,6 @@ impl<'a> QueryBuilder<'a> {
let tokens = lex(self.source);
let mut parser = Parser::new(self.source, tokens);

#[cfg(debug_assertions)]
if let Some(limit) = self.debug_fuel {
parser = parser.with_debug_fuel(limit);
}

if let Some(limit) = self.exec_fuel {
parser = parser.with_exec_fuel(limit);
}
Expand Down