Handle fatal runtime errors (#1151)

* Handle fatal runtime errors

* Wrote "fatal_error" code

* Fix _pyproxy_set

* Fix ownkeys

* Fix PyProxy.toString

src/core/pyproxy.c

@@ -69,10 +69,9 @@ _pyproxy_set(PyObject* pyobj, JsRef idkey, JsRef idval)
   Py_DECREF(pyval);
 
   if (result) {
-    pythonexc2js();
     return NULL;
   }
-  return idval;
+  return hiwire_incref(idval);
 }
 
 JsRef
@@ -89,7 +88,6 @@ _pyproxy_deleteProperty(PyObject* pyobj, JsRef idkey)
   Py_DECREF(pykey);
 
   if (ret) {
-    pythonexc2js();
     return NULL;
   }
 
@@ -102,7 +100,6 @@ _pyproxy_ownKeys(PyObject* pyobj)
   PyObject* pydir = PyObject_Dir(pyobj);
 
   if (pydir == NULL) {
-    pythonexc2js();
     return NULL;
   }
 
@@ -133,7 +130,6 @@ _pyproxy_apply(PyObject* pyobj, JsRef idargs)
   PyObject* pyresult = PyObject_Call(pyobj, pyargs, NULL);
   if (pyresult == NULL) {
     Py_DECREF(pyargs);
-    pythonexc2js();
     return NULL;
   }
   JsRef idresult = python2js(pyresult);
@@ -191,7 +187,15 @@ EM_JS(int, pyproxy_init, (), {
   Module.PyProxyPublicMethods = {
     toString : function() {
       let ptrobj = _getPtr(this);
-      let jsref_repr = __pyproxy_repr(ptrobj);
+      let jsref_repr;
+      try {
+        jsref_repr = __pyproxy_repr(ptrobj);
+      } catch(e){
+        Module.fatal_error(e);
+      }
+      if(jsref_repr === 0){
+        _pythonexc2js();
+      }
       let repr = Module.hiwire.get_value(jsref_repr);
       Module.hiwire.decref(jsref_repr);
       return repr;
@@ -204,10 +208,19 @@ EM_JS(int, pyproxy_init, (), {
     apply : function(jsthis, jsargs) {
       let ptrobj = _getPtr(this);
       let idargs = Module.hiwire.new_value(jsargs);
-      let idresult = __pyproxy_apply(ptrobj, idargs);
+      let idresult;
+      try {
+        idresult = __pyproxy_apply(ptrobj, idargs);
+      } catch(e){
+        Module.fatal_error(e);
+      } finally {
+        Module.hiwire.decref(idargs);
+      }
+      if(idresult === 0){
+        _pythonexc2js();
+      }
       let jsresult = Module.hiwire.get_value(idresult);
       Module.hiwire.decref(idresult);
-      Module.hiwire.decref(idargs);
       return jsresult;
     },
   };
@@ -224,9 +237,18 @@ EM_JS(int, pyproxy_init, (), {
       }
       let ptrobj = _getPtr(jsobj);
       let idkey = Module.hiwire.new_value(jskey);
-      let result = __pyproxy_has(ptrobj, idkey) !== 0;
-      Module.hiwire.decref(idkey);
-      return result;
+      let result;
+      try {
+        result = __pyproxy_has(ptrobj, idkey);
+      } catch(e){
+        Module.fatal_error(e);
+      } finally {
+        Module.hiwire.decref(idkey);
+      }
+      if(result === -1){
+        _pythonexc2js();
+      }
+      return result !== 0;
     },
     get: function (jsobj, jskey) {
       if(Reflect.has(jsobj, jskey) && !ignoredTargetFields.includes(jskey)){
@@ -234,9 +256,18 @@ EM_JS(int, pyproxy_init, (), {
       }
       let ptrobj = _getPtr(jsobj);
       let idkey = Module.hiwire.new_value(jskey);
-      let idresult = __pyproxy_get(ptrobj, idkey);
+      let idresult;
+      try {
+        idresult = __pyproxy_get(ptrobj, idkey);
+      } catch(e) {
+        Module.fatal_error(e);
+      } finally {
+        Module.hiwire.decref(idkey);
+      }
+      if(idresult === 0){
+        _pythonexc2js();
+      }
       let jsresult = Module.hiwire.get_value(idresult);
-      Module.hiwire.decref(idkey);
       Module.hiwire.decref(idresult);
       return jsresult;
     },
@@ -247,10 +278,19 @@ EM_JS(int, pyproxy_init, (), {
       let ptrobj = _getPtr(jsobj);
       let idkey = Module.hiwire.new_value(jskey);
       let idval = Module.hiwire.new_value(jsval);
-      let idresult = __pyproxy_set(ptrobj, idkey, idval);
+      let idresult;
+      try {
+        idresult = __pyproxy_set(ptrobj, idkey, idval);
+      } catch(e) {
+        Module.fatal_error(e);
+      } finally {
+        Module.hiwire.decref(idkey);
+        Module.hiwire.decref(idval);
+      }
+      if(idresult === 0){
+        _pythonexc2js();
+      }
       let jsresult = Module.hiwire.get_value(idresult);
-      Module.hiwire.decref(idkey);
-      Module.hiwire.decref(idval);
       Module.hiwire.decref(idresult);
       return jsresult;
     },
@@ -260,10 +300,19 @@ EM_JS(int, pyproxy_init, (), {
       }
       let ptrobj = _getPtr(jsobj);
       let idkey = Module.hiwire.new_value(jskey);
-      let idresult = __pyproxy_deleteProperty(ptrobj, idkey);
+      let idresult;
+      try {
+        idresult = __pyproxy_deleteProperty(ptrobj, idkey);
+      } catch(e) {
+        Module.fatal_error(e);
+      } finally {
+        Module.hiwire.decref(idkey);
+      }
+      if(idresult === 0){
+        _pythonexc2js();
+      }
       let jsresult = Module.hiwire.get_value(idresult);
       Module.hiwire.decref(idresult);
-      Module.hiwire.decref(idkey);
       return jsresult;
     },
     ownKeys: function (jsobj) {
@@ -272,7 +321,12 @@ EM_JS(int, pyproxy_init, (), {
         result.delete(key);
       }
       let ptrobj = _getPtr(jsobj);
-      let idresult = __pyproxy_ownKeys(ptrobj);
+      let idresult;
+      try {
+        idresult = __pyproxy_ownKeys(ptrobj);
+      } catch(e) {
+        Module.fatal_error(e);
+      }
       let jsresult = Module.hiwire.get_value(idresult);
       Module.hiwire.decref(idresult);
       for(let key of jsresult){

src/core/python2js.c

@@ -358,11 +358,6 @@ python2js_with_depth(PyObject* x, int depth)
   PyObject* map = PyDict_New();
   JsRef result = _python2js_cache(x, map, depth);
   Py_DECREF(map);
-
-  if (result == NULL) {
-    pythonexc2js();
-  }
-
   return result;
 }
 

src/pyodide.js

@@ -319,6 +319,7 @@ globalThis.languagePluginLoader = new Promise((resolve, reject) => {
 
   function makePublicAPI(module, public_api) {
     let namespace = {_module : module};
+    module.public_api = namespace;
     for (let name of public_api) {
       namespace[name] = module[name];
     }
@@ -336,6 +337,27 @@ globalThis.languagePluginLoader = new Promise((resolve, reject) => {
   Module.preloadedWasm = {};
   let isFirefox = navigator.userAgent.toLowerCase().indexOf('firefox') > -1;
 
+  Module.fatal_error = function(e) {
+    for (let [key, value] of Object.entries(Module.public_api)) {
+      if (key.startsWith("_")) {
+        // delete Module.public_api[key];
+        continue;
+      }
+      // Have to do this case first because typeof(some_pyproxy) === "function".
+      if (Module.PyProxy.isPyProxy(value)) {
+        value.destroy();
+        continue;
+      }
+      if (typeof (value) === "function") {
+        Module.public_api[key] = function() {
+          throw Error("Pyodide has suffered a fatal error, refresh the page. " +
+                      "Please report this to the Pyodide maintainers.");
+        }
+      }
+    }
+    throw e;
+  };
+
   Module.runPython = code => Module.pyodide_py.eval_code(code, Module.globals);
 
   // clang-format off

src/tests/test_stdlib_fixes.py

@@ -30,7 +30,7 @@ def test_threading_import(selenium):
     selenium.run(
         """
         import threading
-        threading.local()
+        threading.local(); pass
         """
     )