fix(wasm): use patched sharded-slab with manual thread state release

Cargo.toml

@@ -148,6 +148,7 @@ sct = { version = "0.7" }
 semver = { version = "1.0" }
 serde = { version = "1.0" }
 serde_json = { version = "1.0" }
+sharded-slab = { version = "0.1" }
 sha2 = { version = "0.10" }
 signature = { version = "2.2" }
 thiserror = { version = "1.0" }
@@ -162,9 +163,14 @@ tracing = { version = "0.1" }
 tracing-subscriber = { version = "0.3" }
 wasm-bindgen = { version = "0.2" }
 wasm-bindgen-futures = { version = "0.4" }
-web-spawn = { version = "0.2" }
+web-spawn = { git = "https://github.com/tlsnotary/tlsn-utils", rev = "f674edd" }
 web-time = { version = "0.2" }
 webpki-roots = { version = "1.0" }
 webpki-root-certs = { version = "1.0" }
 ws_stream_wasm = { version = "0.7.5" }
 zeroize = { version = "1.8" }
+
+[patch.crates-io]
+# Replace sharded-slab with a wasm-friendly fork that provides explicit
+# thread-id cleanup (wasm-bindgen does not run Rust TLS destructors).
+sharded-slab = { git = "https://github.com/tlsnotary/sharded-slab" }

crates/harness/executor/Cargo.toml

@@ -5,8 +5,7 @@ edition = "2024"
 publish = false
 
 [features]
-# Disable tracing events as a workaround for issue 959. 
-default = ["tracing/release_max_level_off"]
+default = []
 # Used to debug the executor itself.
 debug = []
 

crates/harness/executor/src/wasm.rs

@@ -12,6 +12,7 @@ use harness_core::{
 
 use crate::Executor;
 
+#[allow(unused_imports)]
 pub use tlsn_wasm::*;
 
 unsafe extern "C" {

crates/wasm/Cargo.toml

@@ -38,6 +38,7 @@ pin-project-lite = { workspace = true }
 rayon = { workspace = true }
 serde = { workspace = true, features = ["derive"] }
 serde_json = { version = "1.0" }
+sharded-slab = { workspace = true }
 time = { version = "=0.3.37", features = ["wasm-bindgen"] }
 tracing = { workspace = true }
 tracing-subscriber = { workspace = true, features = ["time"] }

crates/wasm/src/log.rs

@@ -123,3 +123,16 @@ pub(crate) fn filter(config: LoggingConfig) -> impl Fn(&Metadata) -> bool {
         meta.level() <= level
     }
 }
+
+#[no_mangle]
+pub(crate) extern "C" fn __worker_teardown() {
+    use sharded_slab::DefaultConfig;
+    // Manually release sharded_slab's per-thread state.
+    //
+    // On native targets this would normally be cleaned up by Rust's
+    // thread-local destructors when a thread exits. However, in the
+    // wasm32 + wasm-bindgen threading model, TLS destructors are not
+    // invoked when a Web Worker is terminated. As a result, we must
+    // perform this cleanup explicitly before the worker is destroyed.
+    sharded_slab::release_current_thread_id::<DefaultConfig>();
+}