Merge pull request #87 from mdboom/call-stack-size-exceeded

Decrease Python call stack size so it doesn't exceed JS call stack

src/jsproxy.c

@@ -268,9 +268,9 @@ JsProxy_GetBuffer(PyObject* o, Py_buffer* view, int flags)
 
   Py_ssize_t byteLength = hiwire_get_byteLength(self->js);
 
-  void *ptr;
+  void* ptr;
   if (hiwire_is_on_wasm_heap(self->js)) {
-    ptr = (void *)hiwire_get_byteOffset(self->js);
+    ptr = (void*)hiwire_get_byteOffset(self->js);
   } else {
     if (self->bytes == NULL) {
       self->bytes = PyBytes_FromStringAndSize(NULL, byteLength);
@@ -347,8 +347,9 @@ JsProxy_GetBuffer(PyObject* o, Py_buffer* view, int flags)
 }
 
 static PyObject*
-JsProxy_HasBytes(PyObject *o) {
-  JsProxy* self = (JsProxy *)o;
+JsProxy_HasBytes(PyObject* o)
+{
+  JsProxy* self = (JsProxy*)o;
 
   if (self->bytes == NULL) {
     Py_RETURN_FALSE;

src/pyodide.js

@@ -69,6 +69,32 @@ var languagePluginLoader = new Promise((resolve, reject) => {
     return promise;
   };
 
+  function fixRecursionLimit(pyodide) {
+    // The Javascript/Wasm call stack may be too small to handle the default
+    // Python call stack limit of 1000 frames. This is generally the case on
+    // Chrom(ium), but not on Firefox. Here, we determine the Javascript call
+    // stack depth available, and then divide by 50 (determined heuristically)
+    // to set the maximum Python call stack depth.
+
+    let depth = 0;
+    function recurse() {
+      depth += 1;
+      recurse();
+    }
+    try {
+      recurse();
+    } catch (err) {
+      ;
+    }
+
+    let recursionLimit = depth / 50;
+    if (recursionLimit > 1000) {
+      recursionLimit = 1000;
+    }
+    pyodide.runPython(
+        `import sys; sys.setrecursionlimit(int(${recursionLimit}))`);
+  };
+
   ////////////////////////////////////////////////////////////
   // Loading Pyodide
   let wasmURL = `${baseURL}pyodide.asm.wasm`;
@@ -98,6 +124,7 @@ var languagePluginLoader = new Promise((resolve, reject) => {
           .then((response) => response.json())
           .then((json) => {
             window.pyodide.packages = json;
+            fixRecursionLimit(pyodide);
             resolve();
           });
     };

src/runpython.c

@@ -9,19 +9,19 @@
 
 extern PyObject* globals;
 
-PyObject *eval_code;
+PyObject* eval_code;
 
 int
 _runPython(char* code)
 {
-  PyObject *py_code;
+  PyObject* py_code;
   py_code = PyUnicode_FromString(code);
   if (py_code == NULL) {
     return pythonexc2js();
   }
 
-  PyObject *ret = PyObject_CallFunctionObjArgs(
-      eval_code, py_code, globals, NULL);
+  PyObject* ret =
+    PyObject_CallFunctionObjArgs(eval_code, py_code, globals, NULL);
 
   if (ret == NULL) {
     return pythonexc2js();
@@ -46,13 +46,15 @@ EM_JS(int, runpython_init_js, (), {
   return 0;
 });
 
-int runpython_init_py() {
-  PyObject *m = PyImport_ImportModule("pyodide");
+int
+runpython_init_py()
+{
+  PyObject* m = PyImport_ImportModule("pyodide");
   if (m == NULL) {
     return 1;
   }
 
-  PyObject *d = PyModule_GetDict(m);
+  PyObject* d = PyModule_GetDict(m);
   if (d == NULL) {
     return 1;
   }

test/conftest.py

@@ -53,7 +53,11 @@ class SeleniumWrapper:
             'return pyodide.runPython({!r})'.format(code))
 
     def run_js(self, code):
-        return self.driver.execute_script(code)
+        catch = f"""
+            Error.stackTraceLimit = Infinity;
+            try {{ {code} }}
+            catch (error) {{ console.log(error.stack); throw error; }}"""
+        return self.driver.execute_script(catch)
 
     def load_package(self, packages):
         self.run_js(

test/test_python.py

-import os
 import pathlib
 import time
 
@@ -281,13 +280,13 @@ def test_run_core_python_test(python_test, selenium):
             "from test.libregrtest import main\n"
             "main(['{}'], verbose=True, verbose3=True)".format(python_test))
     except selenium.JavascriptException as e:
-        assert str(e).strip().endswith('SystemExit: 0')
+        assert 'SystemExit: 0' in str(e)
 
 
 def pytest_generate_tests(metafunc):
     if 'python_test' in metafunc.fixturenames:
         test_modules = []
-        if 'CIRCLECI' not in os.environ:
+        if True:
             with open(
                     str(pathlib.Path(__file__).parents[0] /
                         "python_tests.txt")) as fp:
@@ -299,3 +298,15 @@ def pytest_generate_tests(metafunc):
                     if len(parts) == 1:
                         test_modules.append(parts[0])
         metafunc.parametrize("python_test", test_modules)
+
+
+def test_recursive_repr(selenium):
+    assert not selenium.run(
+        "d = {}\n"
+        "d[42] = d.values()\n"
+        "result = True\n"
+        "try:\n"
+        "   repr(d)\n"
+        "except RecursionError:\n"
+        "   result = False\n"
+        "result")