fix(ext/ffi): Avoid keeping JsRuntimeState RefCell borrowed for event loop middleware calls (#15116)

1 files changed, 64 insertions, 0 deletions

diff --git a/test_ffi/tests/event_loop_integration.ts b/test_ffi/tests/event_loop_integration.ts
new file mode 100644
index 000000000..c3b34cc8f
--- /dev/null
+++ b/test_ffi/tests/event_loop_integration.ts
@@ -0,0 +1,64 @@
+const targetDir = Deno.execPath().replace(/[^\/\\]+$/, "");
+const [libPrefix, libSuffix] = {
+  darwin: ["lib", "dylib"],
+  linux: ["lib", "so"],
+  windows: ["", "dll"],
+}[Deno.build.os];
+const libPath = `${targetDir}/${libPrefix}test_ffi.${libSuffix}`;
+
+const dylib = Deno.dlopen(
+  libPath,
+  {
+    store_function: {
+      parameters: ["function"],
+      result: "void",
+    },
+    call_stored_function: {
+      parameters: [],
+      result: "void",
+    },
+    call_stored_function_thread_safe_and_log: {
+      parameters: [],
+      result: "void",
+    },
+  } as const,
+);
+
+const tripleLogCallback = () => {
+  console.log("Sync");
+  Promise.resolve().then(() => {
+    console.log("Async");
+    callback.unref();
+  });
+  setTimeout(() => {
+    console.log("Timeout");
+    callback.unref();
+  }, 10);
+};
+
+const callback = new Deno.UnsafeCallback(
+  {
+    parameters: [],
+    result: "void",
+  } as const,
+  tripleLogCallback,
+);
+
+// Store function
+dylib.symbols.store_function(callback.pointer);
+
+// Synchronous callback logging
+console.log("SYNCHRONOUS");
+dylib.symbols.call_stored_function();
+console.log("STORED_FUNCTION called");
+
+// Wait to make sure synch logging and async logging
+await new Promise((res) => setTimeout(res, 100));
+
+// Ref twice to make sure both `Promise.resolve().then()` and `setTimeout()`
+// must resolve before isolate exists.
+callback.ref();
+callback.ref();
+
+console.log("THREAD SAFE");
+dylib.symbols.call_stored_function_thread_safe_and_log();