[browser][MT] JSImport with DiscardNoWait is OK in the middle of pend…

…ing synchronous call (#101044)
dotnet · Apr 15, 2024 · 0e6cc4a · 0e6cc4a
1 parent 4f3a2f0
commit 0e6cc4a
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Showing 3 changed files with 5 additions and 1 deletion.
diff --git a/...ces.JavaScript/src/System/Runtime/InteropServices/JavaScript/Interop/JavaScriptExports.cs b/...ces.JavaScript/src/System/Runtime/InteropServices/JavaScript/Interop/JavaScriptExports.cs
@@ -289,6 +289,7 @@ public static void BeforeSyncJSExport(JSMarshalerArgument* arguments_buffer)
             try
             {
                 var ctx = arg_exc.AssertCurrentThreadContext();
+                // note that this method is only executed when the caller is on another thread, via mono_wasm_invoke_jsexport_sync -> mono_wasm_install_js_worker_interop_wrapper
                 ctx.IsPendingSynchronousCall = true;
                 if (ctx.IsMainThread)
                 {

diff --git a/...ropServices.JavaScript/src/System/Runtime/InteropServices/JavaScript/JSFunctionBinding.cs b/...ropServices.JavaScript/src/System/Runtime/InteropServices/JavaScript/JSFunctionBinding.cs
@@ -307,7 +307,7 @@ internal static unsafe void InvokeJSImportImpl(JSFunctionBinding signature, Span
 #if FEATURE_WASM_MANAGED_THREADS
             else
             {
-                if (targetContext.IsPendingSynchronousCall && targetContext.IsMainThread)
+                if (targetContext.IsPendingSynchronousCall && targetContext.IsMainThread && !signature.IsDiscardNoWait)
                 {
                     throw new PlatformNotSupportedException("Cannot call synchronous JS function from inside a synchronous call to a C# method.");
                 }

diff --git a/...vices.JavaScript.UnitTests/System/Runtime/InteropServices/JavaScript/WebWorkerTestBase.cs b/...vices.JavaScript.UnitTests/System/Runtime/InteropServices/JavaScript/WebWorkerTestBase.cs
@@ -180,6 +180,9 @@ static void LocalCtsIgnoringCall(Action<CancellationToken> action)
             new NamedCall { IsBlocking = false, Name = "new Timer", Call = delegate (CancellationToken ct) {
                 new Timer((_) => { }, null, 1, -1);
             }},
+            new NamedCall { IsBlocking = false, Name = "JSType.DiscardNoWait", Call = delegate (CancellationToken ct) {
+                WebWorkerTestHelper.Log("DiscardNoWait");
+            }},
 
             // things which should throw PNSE on sync JSExport and JSWebWorker
             new NamedCall { IsBlocking = true, Name = "Task.Wait", Call = delegate (CancellationToken ct) { Task.Delay(30, ct).Wait(ct); }},