fix: guard ProfilerInstant against wasm32 Instant::now() panic#181
fix: guard ProfilerInstant against wasm32 Instant::now() panic#181eliothedeman wants to merge 1 commit intofacebook:mainfrom
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On wasm32-unknown-unknown, std::time::Instant::now() panics at runtime (time not implemented on this platform). ProfilerInstant is called on every function enter/exit via CallEnter/CallExit heap markers, making the evaluator unusable on WASM. This applies the same cfg(any(test, target_arch = wasm32)) guard pattern already used in eval.rs and modules.rs -- falling back to a monotonic thread-local counter. Profiling data will not reflect real wall-clock time on WASM, but the evaluator works correctly.
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Summary
On
wasm32-unknown-unknown,std::time::Instant::now()panics at runtime ("time not implemented on this platform").ProfilerInstant::now()is called on every function enter/exit viaCallEnter/CallExitheap markers, making the Starlark evaluator unusable on WASM.This applies the same
#[cfg(any(test, target_arch = "wasm32"))]guard pattern already used ineval.rs(line 68) andmodules.rs(#154) — falling back to the existing monotonic thread-local counter. Profiling data won't reflect real wall-clock time on WASM, but the evaluator runs correctly.Context
We're compiling starlark-rust to WASM for a browser-based interactive policy tutorial. The evaluator, module system, and stdlib all work perfectly on
wasm32-unknown-unknown— this was the last remainingInstant::now()call site that needed guarding.Changes
starlark/src/eval/runtime/profile/instant.rs: Replace#[cfg(not(test))]/#[cfg(test)]with#[cfg(not(any(test, target_arch = "wasm32")))]/#[cfg(any(test, target_arch = "wasm32"))]