socket: don't leave exceptions pending when a connect promise settle or TLS session/keylog dispatch fails

packages/bun-usockets/src/internal/fault_inject.h

@@ -48,6 +48,12 @@ enum us_fault_syscall {
      * always fresh from the kernel here, so the failure path is unreachable
      * without fault injection. Only US_FAULT_ERRNO applies. */
     US_FAULT_POLL_START,
+    /* Not a syscall: the JS Buffer allocated for a TLS session/keylog payload
+     * in the Rust on_session/on_keylog dispatch. It only fails on JSC heap
+     * OOM, so the failure path is unreachable without injection. Only
+     * US_FAULT_ERRNO applies, and the errno value is ignored — the simulated
+     * failure is a thrown JS out-of-memory error, not an errno. */
+    US_FAULT_SESSION_BUFFER,
     US_FAULT_COUNT
 };
 

src/js/internal-for-testing.ts

@@ -327,8 +327,8 @@ export const setSocketOptions: setSocketOptionsFn = $newRustFunction(
 /**
  * The syscalls instrumented in bsd.c, plus non-syscall hooks whose failure
  * paths are otherwise unreachable without injection ("ssl_loop_buffer",
- * "poll_start"; see fault_inject.h for the per-hook description). Arming
- * anything else is rejected.
+ * "poll_start", "session_buffer"; see fault_inject.h for the per-hook
+ * description). Arming anything else is rejected.
  */
 export type SocketFaultSyscall =
   | "recv"
@@ -339,7 +339,8 @@ export type SocketFaultSyscall =
   | "connect"
   | "accept"
   | "ssl_loop_buffer"
-  | "poll_start";
+  | "poll_start"
+  | "session_buffer";
 
 export type SocketFaultRule = {
   syscall: SocketFaultSyscall;
@@ -366,7 +367,7 @@ export type SocketFaultRule = {
   after?: number;
   /** fire this many times then disarm; -1 = forever. Default 1. */
   repeat?: number;
-  /** match only this fd; -1 (default) = any. Rejected for "ssl_loop_buffer", which has no fd. */
+  /** match only this fd; -1 (default) = any. Rejected for "ssl_loop_buffer" and "session_buffer", which have no fd. */
   fd?: number;
 };
 

src/runtime/socket/Listener.rs

@@ -1624,7 +1624,7 @@ fn connect_finish<const IS_SSL: bool>(
         };
         {
             let this = socket;
-            let _ = NewSocket::<IS_SSL>::handle_connect_error(this, errno, 0);
+            NewSocket::<IS_SSL>::handle_connect_error(this, errno, 0);
             // Balance the unconditional `socket_ref.ref_()` above.
             NewSocket::deref(&this);
         }

src/runtime/socket/WindowsNamedPipeContext.rs

@@ -192,21 +192,21 @@ impl WindowsNamedPipeContext {
         // Only the TLS wrapper parks sessions; the TCP arm can never get here.
         // SAFETY: see `on_open`.
         if let SocketType::Tls(s) = unsafe { (*this).socket } {
-            let _ = TLSSocket::on_session(s, session);
+            TLSSocket::on_session(s, session);
         }
     }
 
     fn on_keylog(this: *mut Self, line: &[u8]) {
         // SAFETY: see `on_open`.
         if let SocketType::Tls(s) = unsafe { (*this).socket } {
-            let _ = TLSSocket::on_keylog(s, line);
+            TLSSocket::on_keylog(s, line);
         }
     }
 
     fn on_handshake(this: *mut Self, success: bool, ssl_error: us_bun_verify_error_t) {
         // SAFETY: see `on_open`.
         let (socket, pipe) = unsafe { ((*this).socket, ptr::addr_of_mut!((*this).named_pipe)) };
-        match_socket!(socket, |s: NewSocket<SSL>| _ = NewSocket::on_handshake(
+        match_socket!(socket, |s: NewSocket<SSL>| NewSocket::on_handshake(
             s,
             socket_from_named_pipe::<SSL>(pipe),
             success as i32,
@@ -243,8 +243,11 @@ impl WindowsNamedPipeContext {
                 s.handle_error(js_err);
             });
         } else {
-            match_socket!(socket, |s: NewSocket<SSL>| _ =
-                NewSocket::handle_connect_error(s, err.errno as i32, 0));
+            match_socket!(socket, |s: NewSocket<SSL>| NewSocket::handle_connect_error(
+                s,
+                err.errno as i32,
+                0
+            ));
         }
     }
 
@@ -266,7 +269,7 @@ impl WindowsNamedPipeContext {
             (socket, ptr::addr_of_mut!((*this).named_pipe))
         };
         match_socket!(socket, |s: NewSocket<SSL>| {
-            _ = NewSocket::on_close(s, socket_from_named_pipe::<SSL>(pipe), 0, None);
+            NewSocket::on_close(s, socket_from_named_pipe::<SSL>(pipe), 0, None);
             // Release the +1 ref taken in `create()`.
             s.get().deref();
         });
@@ -302,8 +305,9 @@ impl WindowsNamedPipeContext {
     fn fail_and_release(this: *mut Self) {
         // SAFETY: `this` is live; `create()` returned it and no deref has fired yet.
         // +1 ref held on the inner socket; live until `Self::deref` below.
-        match_socket!(unsafe { (*this).socket }, |s: NewSocket<SSL>| _ =
-            NewSocket::handle_connect_error(s, SystemErrno::ENOENT as i32, 0));
+        match_socket!(unsafe { (*this).socket }, |s: NewSocket<SSL>| {
+            NewSocket::handle_connect_error(s, SystemErrno::ENOENT as i32, 0)
+        });
         // SAFETY: `this` was just returned from `create()` (refcount==1);
         // release the only ref on the errdefer path.
         unsafe { Self::deref(this) };

src/runtime/socket/mod.rs

@@ -146,7 +146,7 @@ impl<const SSL: bool> uws_handlers::RawSocketEvents<SSL> for NewSocket<SSL> {
         code: i32,
         reason: *mut core::ffi::c_void,
     ) {
-        let _ = NewSocket::on_close(
+        NewSocket::on_close(
             this,
             s,
             code,
@@ -167,7 +167,7 @@ impl<const SSL: bool> uws_handlers::RawSocketEvents<SSL> for NewSocket<SSL> {
         s: bun_uws::NewSocketHandler<SSL>,
         code: i32,
     ) {
-        let _ = NewSocket::on_connect_error(this, s, code);
+        NewSocket::on_connect_error(this, s, code);
     }
     #[inline]
     fn on_handshake(
@@ -176,6 +176,6 @@ impl<const SSL: bool> uws_handlers::RawSocketEvents<SSL> for NewSocket<SSL> {
         ok: i32,
         err: bun_uws_sys::us_bun_verify_error_t,
     ) {
-        let _ = NewSocket::on_handshake(this, s, ok, err);
+        NewSocket::on_handshake(this, s, ok, err);
     }
 }