⚡ Bolt: Optimize list literal evaluation - #337
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- Updates `evaluate_literal_direct` to accept `Environment` and recursively evaluate list elements synchronously using `try_evaluate_simple_expr_sync`. - Avoids `Box::pin` allocation and async overhead for list literals where all elements can be evaluated synchronously (e.g., constants, variables, simple math). - Fallback to async evaluation is preserved if any element requires it (e.g., async function call). - Benchmark shows ~2.8x speedup (2742ms -> 968ms) for creating 1 million lists. Co-authored-by: logbie <1138960+logbie@users.noreply.github.com>
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Claude finished @logbie's task —— View job Code Review Complete ✅Reviewing the list literal optimization PR. Here's my comprehensive feedback: Todo List:
📋 Code Review Feedback✅ Overall Assessment: LGTM with Minor SuggestionsThis is a well-implemented optimization that addresses a real performance bottleneck. The approach is sound and the implementation follows good patterns. 🎯 Code Quality & Best PracticesPositive aspects:
Minor suggestion:
🐛 Potential Issues & Edge CasesNo critical bugs found, but consider these edge cases:
⚡ Performance ConsiderationsExcellent optimization approach:
Performance impact assessment:
🔒 Security ConcernsNo security issues identified:
🧪 Test Coverage AssessmentCurrent test coverage:
Recommendations for additional tests: // Consider adding a performance regression test
#[test]
fn test_list_literal_performance() {
// Benchmark simple list creation to catch future regressions
let start = std::time::Instant::now();
for _ in 0..10000 {
// Create lists with simple literals
}
let duration = start.elapsed();
assert!(duration < Duration::from_millis(100)); // Adjust threshold as needed
}
#[test]
fn test_nested_list_optimization() {
// Test that nested lists of literals are optimized
// [[1, 2], [3, 4]] should be evaluated synchronously
}
#[test]
fn test_mixed_sync_async_fallback() {
// Test lists containing both simple literals and function calls
// Should properly fall back to async evaluation
}📍 Specific Code ReferencesThe optimization is implemented in:
🚀 Recommendations
✨ SummaryThis is a solid performance optimization that:
Recommendation: Approve and merge 🎉 |
📝 WalkthroughWalkthroughModified the interpreter's evaluation logic to support synchronous fast-path evaluation of literals and simple expressions. Added environment parameter to Changes
Estimated code review effort🎯 3 (Moderate) | ⏱️ ~20 minutes Possibly related PRs
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🚥 Pre-merge checks | ✅ 2 | ❌ 1❌ Failed checks (1 warning)
✅ Passed checks (2 passed)
✏️ Tip: You can configure your own custom pre-merge checks in the settings. ✨ Finishing touches
🧪 Generate unit tests (beta)
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Pull request overview
Optimizes list literal (Literal::List) evaluation by attempting synchronous evaluation of list elements to avoid per-element Box::pin overhead.
Changes:
- Extends
evaluate_literal_directto acceptenvso list elements can be evaluated synchronously. - Adds a fast path for
Literal::Listthat builds the list directly when all elements are sync-evaluable. - Updates the call site in
try_evaluate_simple_expr_syncto passenvthrough.
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| let mut list_values = Vec::with_capacity(elements.len()); | ||
| for element in elements { | ||
| // Recursively try to evaluate elements synchronously. | ||
| // This works for nested lists as well. | ||
| if let Some(value) = self.try_evaluate_simple_expr_sync(element, env)? { | ||
| list_values.push(value); | ||
| } else { | ||
| // Element requires async evaluation, abort sync optimization for the whole list | ||
| return Ok(None); | ||
| } | ||
| } |
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If a later element requires async evaluation, this returns Ok(None) after already computing earlier elements, which will be recomputed again by the fallback (boxed/async) list path. Consider a two-pass approach (first pass checks whether all elements are sync-evaluable without producing Values; second pass evaluates), or refactor to preserve and reuse the already-evaluated prefix when falling back.
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| if let Some(value) = self.try_evaluate_simple_expr_sync(element, env)? { | ||
| list_values.push(value); | ||
| } else { | ||
| // Element requires async evaluation, abort sync optimization for the whole list | ||
| return Ok(None); |
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The new Literal::List fast path evaluates each element immediately and only returns None when it later encounters a non-sync expression, which causes evaluate_expression to re-run the entire list in _evaluate_expression. In mixed lists (for example [random, some_call(...)] where random is auto-called as a zero-arg native function), earlier elements are executed twice, changing observable behavior (extra RNG/time calls or other side effects) compared to the previous single evaluation path.
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Actionable comments posted: 1
🤖 Fix all issues with AI agents
In `@src/interpreter/mod.rs`:
- Around line 5765-5778: The fast sync path for Literal::List uses
try_evaluate_simple_expr_sync to evaluate elements and returns Ok(None if any
element needs async), which causes already-evaluated earlier elements to be
re-run in the async path and can double-execute side effects; modify the logic
in the Literal::List handling so you first pre-scan elements (calling a
lightweight check like try_evaluate_simple_expr_sync in "probe" mode or adding a
new helper) to detect whether any element requires async without executing
side-effecting evaluations, and if a mix is detected either (1) preserve the
already-evaluated prefix (store values produced so far) and continue evaluation
asynchronously for the remaining elements, or (2) perform a pure pre-scan pass
that only determines async-necessity and then run a single evaluation pass
asynchronously; update try_evaluate_simple_expr_sync or add a new
try_probe_simple_expr_sync helper and ensure the final produced value is wrapped
as Value::List(Rc::new(RefCell::new(...))) as before.
| Literal::List(elements) => { | ||
| let mut list_values = Vec::with_capacity(elements.len()); | ||
| for element in elements { | ||
| // Recursively try to evaluate elements synchronously. | ||
| // This works for nested lists as well. | ||
| if let Some(value) = self.try_evaluate_simple_expr_sync(element, env)? { | ||
| list_values.push(value); | ||
| } else { | ||
| // Element requires async evaluation, abort sync optimization for the whole list | ||
| return Ok(None); | ||
| } | ||
| } | ||
| Ok(Some(Value::List(Rc::new(RefCell::new(list_values))))) | ||
| } |
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Avoid double-evaluation when list sync path falls back to async.
If an element later in the list requires async evaluation, the fast-path returns Ok(None) after already evaluating earlier elements. The async fallback then re-evaluates the entire list, which can duplicate side effects (e.g., zero-arg native functions invoked via auto-call). Consider a two-phase approach (pre-scan for async-needed elements without executing), or preserve the already-evaluated prefix and continue asynchronously for the remainder instead of re-running from scratch.
🤖 Prompt for AI Agents
In `@src/interpreter/mod.rs` around lines 5765 - 5778, The fast sync path for
Literal::List uses try_evaluate_simple_expr_sync to evaluate elements and
returns Ok(None if any element needs async), which causes already-evaluated
earlier elements to be re-run in the async path and can double-execute side
effects; modify the logic in the Literal::List handling so you first pre-scan
elements (calling a lightweight check like try_evaluate_simple_expr_sync in
"probe" mode or adding a new helper) to detect whether any element requires
async without executing side-effecting evaluations, and if a mix is detected
either (1) preserve the already-evaluated prefix (store values produced so far)
and continue evaluation asynchronously for the remaining elements, or (2)
perform a pure pre-scan pass that only determines async-necessity and then run a
single evaluation pass asynchronously; update try_evaluate_simple_expr_sync or
add a new try_probe_simple_expr_sync helper and ensure the final produced value
is wrapped as Value::List(Rc::new(RefCell::new(...))) as before.
💡 What: Optimized
Literal::Listevaluation in the interpreter.🎯 Why: Creating list literals previously incurred significant overhead due to
Box::pinallocation for every element, even if they were simple constants.📊 Impact: ~2.8x speedup in tight loops creating lists. Benchmark reduced from 2742ms to 968ms.
🔬 Measurement: Verified with a benchmark script creating 1 million lists of 10 integers.
PR created automatically by Jules for task 11608627115757947855 started by @logbie
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