Mark asynchronous blocks in Csourcekitd as Sendable

We don’t have any guarantees which thread these blocks will be called on by sourcekitd, so we shouldn’t make any assumptions about it in Swift. We should thus mark them as Sendable.

Author: ahoppen

Sources/Csourcekitd/include/plugin.h

@@ -114,7 +114,7 @@ typedef const void *_Null_unspecified (*sourcekitd_api_variant_functions_data_ge
 typedef bool (^sourcekitd_api_cancellable_request_handler_t)(
   _Null_unspecified sourcekitd_api_object_t,
   _Null_unspecified sourcekitd_api_request_handle_t,
-  void (^_Null_unspecified __attribute__((swift_attr("@Sendable"))))(_Null_unspecified sourcekitd_api_response_t)
+  void (^_Null_unspecified SWIFT_SENDABLE)(_Null_unspecified sourcekitd_api_response_t)
 );
 typedef void (^sourcekitd_api_cancellation_handler_t)(_Null_unspecified sourcekitd_api_request_handle_t);
 typedef _Null_unspecified sourcekitd_api_uid_t (*sourcekitd_api_uid_get_from_cstr_t)(const char *_Null_unspecified string);
@@ -233,11 +233,11 @@ typedef struct {
     _Null_unspecified sourcekitd_api_plugin_initialize_params_t
   );
 
-  _Null_unspecified sourcekitd_api_uid_get_from_cstr_t (*_Nonnull plugin_initialize_uid_get_from_cstr)(
+  _Null_unspecified SWIFT_SENDABLE sourcekitd_api_uid_get_from_cstr_t (*_Nonnull plugin_initialize_uid_get_from_cstr)(
     _Null_unspecified sourcekitd_api_plugin_initialize_params_t
   );
 
-  _Null_unspecified sourcekitd_api_uid_get_string_ptr_t (*_Nonnull plugin_initialize_uid_get_string_ptr)(
+  _Null_unspecified SWIFT_SENDABLE sourcekitd_api_uid_get_string_ptr_t (*_Nonnull plugin_initialize_uid_get_string_ptr)(
     _Null_unspecified sourcekitd_api_plugin_initialize_params_t
   );
 
@@ -251,7 +251,7 @@ typedef struct {
 typedef struct {
   void (*_Nonnull plugin_initialize_register_cancellable_request_handler)(
     _Nonnull sourcekitd_api_plugin_initialize_params_t,
-    _Nonnull sourcekitd_api_cancellable_request_handler_t
+    _Nonnull SWIFT_SENDABLE sourcekitd_api_cancellable_request_handler_t
   );
 
   /// Adds a function that will be called when a request is cancelled.
@@ -260,7 +260,7 @@ typedef struct {
   /// handle to be cancelled, it should ignore the cancellation request.
   void (*_Nonnull plugin_initialize_register_cancellation_handler)(
     _Nonnull sourcekitd_api_plugin_initialize_params_t,
-    _Nonnull sourcekitd_api_cancellation_handler_t
+    _Nonnull SWIFT_SENDABLE sourcekitd_api_cancellation_handler_t
   );
 
   void *_Null_unspecified(*_Nonnull plugin_initialize_get_swift_ide_inspection_instance)(

Sources/Csourcekitd/include/sourcekitd_functions.h

@@ -17,6 +17,8 @@
 #include <stddef.h>
 #include <stdint.h>
 
+#define SWIFT_SENDABLE __attribute__((__swift_attr__("@Sendable")))
+
 // Avoid including <sourcekitd/sourcekitd.h> to make sure we don't call the
 // functions directly. But we need the types to form the function pointers.
 // These are supposed to stay stable across toolchains.
@@ -315,17 +317,17 @@ typedef struct {
   void (*_Nonnull send_request)(
     sourcekitd_api_object_t _Nonnull req,
     _Nullable sourcekitd_api_request_handle_t *_Nullable out_handle,
-    _Nullable sourcekitd_api_response_receiver_t receiver
+    _Nullable SWIFT_SENDABLE sourcekitd_api_response_receiver_t receiver
   );
   void (*_Nonnull cancel_request)(
     _Nullable sourcekitd_api_request_handle_t handle
   );
   void (*_Nonnull set_notification_handler)(
-    _Nullable sourcekitd_api_response_receiver_t receiver
+    _Nullable SWIFT_SENDABLE sourcekitd_api_response_receiver_t receiver
   );
   void (*_Nonnull set_uid_handlers)(
-    _Nullable sourcekitd_api_uid_from_str_handler_t uid_from_str,
-    _Nullable sourcekitd_api_str_from_uid_handler_t str_from_uid
+    _Nullable SWIFT_SENDABLE sourcekitd_api_uid_from_str_handler_t uid_from_str,
+    _Nullable SWIFT_SENDABLE sourcekitd_api_str_from_uid_handler_t str_from_uid
   );
 } sourcekitd_api_functions_t;
 

Sources/SourceKitD/SourceKitD.swift

@@ -103,7 +103,7 @@ package actor SourceKitD {
   package let path: URL
 
   /// The handle to the dylib.
-  let dylib: DLHandle
+  private let dylib: DLHandle
 
   /// The sourcekitd API functions.
   nonisolated package let api: sourcekitd_api_functions_t