n-api: detect deadlocks in thread-safe function

We introduce status `napi_would_deadlock` to be used as a return status
by `napi_call_threadsafe_function` if the call is made with
`napi_tsfn_blocking` on the main thread and the queue is full.

PR-URL: https://github.com/nodejs/node/pull/32689
Fixes: https://github.com/nodejs/node/issues/32615
Signed-off-by: Gabriel Schulhof <gabriel.schulhof@intel.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: David Carlier <devnexen@gmail.com>
Reviewed-By: Chengzhong Wu <legendecas@gmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>

1 files changed, 8 insertions, 3 deletions

diff --git a/test/node-api/test_threadsafe_function/test.js b/test/node-api/test_threadsafe_function/test.js
index 3603d79ee6..f5afe225f0 100644
--- a/test/node-api/test_threadsafe_function/test.js
+++ b/test/node-api/test_threadsafe_function/test.js
@@ -210,8 +210,13 @@ new Promise(function testWithoutJSMarshaller(resolve) {
 }))
 .then((result) => assert.strictEqual(result.indexOf(0), -1))
 
-// Start a child process to test rapid teardown
+// Start a child process to test rapid teardown.
 .then(() => testUnref(binding.MAX_QUEUE_SIZE))
 
-// Start a child process with an infinite queue to test rapid teardown
-.then(() => testUnref(0));
+// Start a child process with an infinite queue to test rapid teardown.
+.then(() => testUnref(0))
+
+// Test deadlock prevention.
+.then(() => assert.deepStrictEqual(binding.TestDeadlock(), {
+  deadlockTest: 'Main thread would deadlock'
+}));