swc-project/swc - CodSpeed

swc

Blog Docs Changelog

Performance History

Latest Results

test(es/typescript): Cover const initializers under mutable enums Extends the existing `ts_enum_is_mutable_true` case with both sides of the guard: a const initialized from a mutable enum member, which must stay a runtime read, and one from a `const enum` member, which still folds. Both fail on main — the first because the value was folded away, the second because it was not folded at all.

baltasarblanco:fix/11715-ts-enum-const-var-folding

8 hours ago

perf(es/typescript): Skip const initializers that cannot be constant `compute` takes the initializer by value, so the collection pass cloned every `const` initializer in the program, while most of them hit the `Opaque` catch-all right away: in real TypeScript they are mostly arrow functions, object literals and calls. Check the outermost form before cloning. `es/transform/baseline/common_typescript` goes from 59.6 us back to 53.3 us, against 53.3 us on main. No test output changes.

baltasarblanco:fix/11715-ts-enum-const-var-folding

16 hours ago

test(es/typescript): Update constEnum2 tsc reference `g = CONST` now resolves to a constant, so the member is inlined and no longer emitted, matching how `d = 10` is already handled in the same `const enum`. The remaining members stay opaque because they call `Math.random()`.

baltasarblanco:fix/11715-ts-enum-const-var-folding

18 hours ago

chore: Add changeset

baltasarblanco:fix/11715-ts-enum-const-var-folding

19 hours ago

fix(flow): preserve component semantics without AST break

fix/flow-component-type-semantics

1 day ago

fix(plugin/runner): write Wasmer cache atomically (#12100) **Description:** This fixes intermittent Wasmer plugin cache corruption when multiple processes compile the same plugin concurrently. The Wasmer backend previously serialized modules directly to the final cache path. Parallel Jest, Turbo, or Nx workers could observe the file after its metadata header was written but before the complete artifact was available, producing `metadata_len` slice-bound failures. The backend now serializes the module in memory, writes it to a unique temporary file in the cache directory, and atomically renames the completed file into place. A concurrent-writer regression test verifies that readers only observe complete cache artifacts. **Related issue (if exists):** Fixes #6467 **Validation:** - `cargo test -p swc_plugin_backend_wasmer` - `cargo fmt --all` - `cargo clippy --all --all-targets -- -D warnings`

main

1 day ago

chore: Add changeset

kdy1/fix-wasmer-cache-atomic-write

1 day ago

fix(hstr): avoid references to uninitialized bytes (#12087) **Description:** Fixes two soundness issues in `hstr` where mutable byte references were formed over uninitialized storage. - Use an initialized 64-byte stack buffer in `Atom::from_mutated_str`, retaining the stack fast path and heap fallback for longer strings. - Encode WTF-8 code points through `Vec::spare_capacity_mut()` and `MaybeUninit::write`, updating the vector length only after the exact encoded byte count is initialized. - Document the safety invariants for retained unsafe operations. - Add focused regression coverage for short, 64-byte, and over-64-byte ASCII case conversion and one- through four-byte code-point appends, including an unpaired surrogate. Validation: - `cargo test -p hstr` - Focused Miri runs for both new regression tests - `cargo fmt --all` - `cargo clippy --all --all-targets -- -D warnings` **Related issue (if exists):** Closes #12083 --------- Co-authored-by: Labor0 Bot <279936132+labor0-bot[bot]@users.noreply.github.com>

main

1 day ago

Latest Branches

-2%

fix(es/typescript): Treat const variable references as enum constants#12101

8 hours ago

2e8749f

baltasarblanco:fix/11715-ts-enum-const-var-folding

0%

fix(es/typescript): preserve Flow component type semantics#12090

1 day ago

37e28bd

fix/flow-component-type-semantics

0%

fix(plugin/runner): write Wasmer cache atomically#12100

1 day ago

0d59848

kdy1/fix-wasmer-cache-atomic-write

© 2026 CodSpeed Technology

Home Terms Privacy Docs