[next] Better Errors - Worker (#1602)

pyscript.core/esm/worker/_template.js

@@ -30,8 +30,12 @@ const add = (type, fn) => {
         type,
         fn ||
             (async (event) => {
-                await interpreter;
-                runEvent(`xworker.on${type}`, event);
+                try {
+                    await interpreter;
+                    runEvent(`xworker.on${type}`, event);
+                } catch (error) {
+                    postMessage(error);
+                }
             }),
         !!fn && { once: true },
     );
@@ -55,43 +59,47 @@ const xworker = {
 
 add("message", ({ data: { options, code, hooks } }) => {
     interpreter = (async () => {
-        const { type, version, config, async: isAsync } = options;
-        const interpreter = await getRuntime(
-            getRuntimeID(type, version),
-            config,
-        );
-        const details = create(registry.get(type));
-        const name = `run${isAsync ? "Async" : ""}`;
+        try {
+            const { type, version, config, async: isAsync } = options;
+            const interpreter = await getRuntime(
+                getRuntimeID(type, version),
+                config,
+            );
+            const details = create(registry.get(type));
+            const name = `run${isAsync ? "Async" : ""}`;
 
-        if (hooks) {
-            // patch code if needed
-            const { beforeRun, beforeRunAsync, afterRun, afterRunAsync } =
-                hooks;
+            if (hooks) {
+                // patch code if needed
+                const { beforeRun, beforeRunAsync, afterRun, afterRunAsync } =
+                    hooks;
 
-            const after = afterRun || afterRunAsync;
-            const before = beforeRun || beforeRunAsync;
+                const after = afterRun || afterRunAsync;
+                const before = beforeRun || beforeRunAsync;
 
-            // append code that should be executed *after* first
-            if (after) {
-                const method = details[name].bind(details);
-                details[name] = (interpreter, code) =>
-                    method(interpreter, `${code}\n${after}`);
-            }
-
-            // prepend code that should be executed *before* (so that after is post-patched)
-            if (before) {
-                const method = details[name].bind(details);
-                details[name] = (interpreter, code) =>
-                    method(interpreter, `${before}\n${code}`);
+                // append code that should be executed *after* first
+                if (after) {
+                    const method = details[name].bind(details);
+                    details[name] = (interpreter, code) =>
+                        method(interpreter, `${code}\n${after}`);
+                }
+
+                // prepend code that should be executed *before* (so that after is post-patched)
+                if (before) {
+                    const method = details[name].bind(details);
+                    details[name] = (interpreter, code) =>
+                        method(interpreter, `${before}\n${code}`);
+                }
             }
+            // set the `xworker` global reference once
+            details.registerJSModule(interpreter, "xworker", { xworker });
+            // simplify runEvent calls
+            runEvent = details.runEvent.bind(details, interpreter);
+            // run either sync or async code in the worker
+            await details[name](interpreter, code);
+            return interpreter;
+        } catch (error) {
+            postMessage(error);
         }
-        // set the `xworker` global reference once
-        details.registerJSModule(interpreter, "xworker", { xworker });
-        // simplify runEvent calls
-        runEvent = details.runEvent.bind(details, interpreter);
-        // run either sync or async code in the worker
-        await details[name](interpreter, code);
-        return interpreter;
     })();
     add("error");
     add("message");

pyscript.core/esm/worker/class.js

@@ -53,5 +53,12 @@ export default (...args) =>
 
         if (isHook) this.onWorkerReady?.(this.interpreter, worker);
 
+        worker.addEventListener("message", (event) => {
+            if (event.data instanceof Error) {
+                event.stopImmediatePropagation();
+                worker.onerror(event);
+            }
+        });
+
         return worker;
     };

pyscript.core/package.json

@@ -69,6 +69,6 @@
         "coincident": "^0.11.1"
     },
     "worker": {
-        "blob": "sha256-Ku7KFQEos4ex24kNmg6mhCafl5jblyxgiWfXyVxhpUk="
+        "blob": "sha256-YJ2S61l39eRltU0ldf3Q7CfCASBa8FrQLLsfXUSzBHc="
     }
 }

pyscript.core/test/error.html

@@ -0,0 +1,28 @@
+<!doctype html>
+<html lang="en">
+    <head>
+        <meta charset="UTF-8" />
+        <meta name="viewport" content="width=device-width,initial-scale=1.0" />
+    </head>
+    <body>
+        <div>See console ➡️</div>
+        <script type="micropython">
+            from xworker import XWorker
+
+            def handle_error(event):
+                print("Python")
+                print(event.data.message)
+
+            w = XWorker('./error.py')
+            w.onerror = handle_error
+        </script>
+        <script type="module">
+            import { XWorker } from "../core.js";
+
+            const w = new XWorker("./error.py", { type: "micropython" });
+            w.onerror = ({ data: error }) => {
+                console.log('JS', error);
+            };
+        </script>
+    </body>
+</html>

pyscript.core/test/error.py

@@ -0,0 +1,3 @@
+# from xworker import xworker
+
+xworker.postMessage("error")