Revert "n-api: detect deadlocks in thread-safe function"

This reverts commit d26ca06c16f497ffa5ac4845a27922d5058a9318 because
it breaks running the tests in debug mode, as
`v8::Isolate::GetCurrent()` is not allowed if no `Isolate` is active
on the current thread.

Refs: https://github.com/nodejs/node/pull/33276
Refs: https://github.com/nodejs/node/pull/32860

PR-URL: https://github.com/nodejs/node/pull/33453
Reviewed-By: Daniel Bevenius <daniel.bevenius@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: David Carlier <devnexen@gmail.com>
Reviewed-By: Gireesh Punathil <gpunathi@in.ibm.com>
Reviewed-By: Gabriel Schulhof <gabriel.schulhof@intel.com>

1 files changed, 13 insertions, 18 deletions

diff --git a/doc/api/n-api.md b/doc/api/n-api.md
index 2af31d3de03..f654685a040 100644
--- a/doc/api/n-api.md
+++ b/doc/api/n-api.md
@@ -462,7 +462,7 @@ typedef enum {
   napi_date_expected,
   napi_arraybuffer_expected,
   napi_detachable_arraybuffer_expected,
-  napi_would_deadlock,
+  napi_would_deadlock,  /* unused */
 } napi_status;
 ```
 
@@ -5124,18 +5124,9 @@ preventing data from being successfully added to the queue. If set to
 `napi_call_threadsafe_function()` never blocks if the thread-safe function was
 created with a maximum queue size of 0.
 
-As a special case, when `napi_call_threadsafe_function()` is called from a
-JavaScript thread, it will return `napi_would_deadlock` if the queue is full
-and it was called with `napi_tsfn_blocking`. The reason for this is that the
-JavaScript thread is responsible for removing items from the queue, thereby
-reducing their number. Thus, if it waits for room to become available on the
-queue, then it will deadlock.
-
-`napi_call_threadsafe_function()` will also return `napi_would_deadlock` if the
-thread-safe function created on one JavaScript thread is called from another
-JavaScript thread. The reason for this is to prevent a deadlock arising from the
-possibility that the two JavaScript threads end up waiting on one another,
-thereby both deadlocking.
+`napi_call_threadsafe_function()` should not be called with `napi_tsfn_blocking`
+from a JavaScript thread, because, if the queue is full, it may cause the
+JavaScript thread to deadlock.
 
 The actual call into JavaScript is controlled by the callback given via the
 `call_js_cb` parameter. `call_js_cb` is invoked on the main thread once for each
@@ -5276,6 +5267,10 @@ This API may be called from any thread which makes use of `func`.
 added: v10.6.0
 napiVersion: 4
 changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/33453
+    description: >
+      Support for `napi_would_deadlock` has been reverted.
   - version: v14.1.0
     pr-url: https://github.com/nodejs/node/pull/32689
     description: >
@@ -5298,13 +5293,13 @@ napi_call_threadsafe_function(napi_threadsafe_function func,
   `napi_tsfn_nonblocking` to indicate that the call should return immediately
   with a status of `napi_queue_full` whenever the queue is full.
 
-This API will return `napi_would_deadlock` if called with `napi_tsfn_blocking`
-from the main thread and the queue is full.
+This API should not be called with `napi_tsfn_blocking` from a JavaScript
+thread, because, if the queue is full, it may cause the JavaScript thread to
+deadlock.
 
 This API will return `napi_closing` if `napi_release_threadsafe_function()` was
-called with `abort` set to `napi_tsfn_abort` from any thread.
-
-The value is only added to the queue if the API returns `napi_ok`.
+called with `abort` set to `napi_tsfn_abort` from any thread. The value is only
+added to the queue if the API returns `napi_ok`.
 
 This API may be called from any thread which makes use of `func`.