RustPython · coolreader18 · Dec 29, 2019 · Dec 17, 2019 · Dec 17, 2019 · Dec 18, 2019
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/src/main.rs b/src/main.rs
@@ -7,9 +7,9 @@ extern crate log;
 use clap::{App, AppSettings, Arg, ArgMatches};
 use rustpython_compiler::compile;
 use rustpython_vm::{
+    exceptions::print_exception,
     match_class,
-    obj::{objint::PyInt, objtuple::PyTuple, objtype},
-    print_exception,
+    obj::{objint::PyInt, objtype},
     pyobject::{ItemProtocol, PyResult},
     scope::Scope,
     util, InitParameter, PySettings, VirtualMachine,
@@ -51,8 +51,7 @@ fn main() {
     // See if any exception leaked out:
     if let Err(err) = res {
         if objtype::isinstance(&err, &vm.ctx.exceptions.system_exit) {
-            let args = vm.get_attribute(err.clone(), "args").unwrap();
-            let args = args.downcast::<PyTuple>().expect("'args' must be a tuple");
+            let args = err.args();
             match args.elements.len() {
                 0 => return,
                 1 => match_class!(match args.elements[0].clone() {

diff --git a/src/shell.rs b/src/shell.rs
@@ -5,9 +5,9 @@ mod rustyline_helper;
 use rustpython_compiler::{compile, error::CompileError, error::CompileErrorType};
 use rustpython_parser::error::ParseErrorType;
 use rustpython_vm::{
+    exceptions::{print_exception, PyBaseExceptionRef},
     obj::objtype,
-    print_exception,
-    pyobject::{ItemProtocol, PyObjectRef, PyResult},
+    pyobject::{ItemProtocol, PyResult},
     scope::Scope,
     VirtualMachine,
 };
@@ -16,7 +16,7 @@ use readline::{Readline, ReadlineResult};
 
 enum ShellExecResult {
     Ok,
-    PyErr(PyObjectRef),
+    PyErr(PyBaseExceptionRef),
     Continue,
 }
 
@@ -118,9 +118,8 @@ pub fn run_shell(vm: &VirtualMachine, scope: Scope) -> PyResult<()> {
             ReadlineResult::Interrupt => {
                 continuing = false;
                 full_input.clear();
-                let keyboard_interrupt = vm
-                    .new_empty_exception(vm.ctx.exceptions.keyboard_interrupt.clone())
-                    .unwrap();
+                let keyboard_interrupt =
+                    vm.new_exception_empty(vm.ctx.exceptions.keyboard_interrupt.clone());
                 Err(keyboard_interrupt)
             }
             ReadlineResult::EOF => {

diff --git a/tests/snippets/try_exceptions.py b/tests/snippets/try_exceptions.py
@@ -250,7 +250,23 @@ def y():
     except ZeroDivisionError as ex:
         raise NameError from ex
 except NameError as ex2:
-    pass
+    assert isinstance(ex2.__cause__, ZeroDivisionError)
+else:
+    assert False, "no raise"
+
+
+try:
+    try:
+        try:
+            raise ZeroDivisionError
+        except ZeroDivisionError as ex:
+            raise NameError from ex
+    except NameError:
+        raise
+except NameError as ex2:
+    assert isinstance(ex2.__cause__, ZeroDivisionError)
+else:
+    assert False, "no raise"
 
 
 # the else clause requires at least one except clause:

diff --git a/vm/Cargo.toml b/vm/Cargo.toml
@@ -49,7 +49,7 @@ chrono = { version = "=0.4.9", features = ["wasmbind"] }
 unicode-xid = "0.2.0"
 lazy_static = "^1.0.1"
 lexical = "4"
-itertools = "^0.8.0"
+itertools = "0.8"
 hex = "0.4.0"
 hexf-parse = "0.1.0"
 indexmap = "1.0.2"

diff --git a/vm/src/builtins.rs b/vm/src/builtins.rs
@@ -12,6 +12,7 @@ use num_traits::{Signed, ToPrimitive, Zero};
 #[cfg(feature = "rustpython-compiler")]
 use rustpython_compiler::compile;
 
+use crate::exceptions::PyBaseExceptionRef;
 use crate::function::{single_or_tuple_any, Args, KwArgs, OptionalArg, PyFuncArgs};
 use crate::obj::objbool::{self, IntoPyBool};
 use crate::obj::objbyteinner::PyByteInner;
@@ -290,7 +291,7 @@ fn builtin_format(
         })
 }
 
-fn catch_attr_exception<T>(ex: PyObjectRef, default: T, vm: &VirtualMachine) -> PyResult<T> {
+fn catch_attr_exception<T>(ex: PyBaseExceptionRef, default: T, vm: &VirtualMachine) -> PyResult<T> {
     if objtype::isinstance(&ex, &vm.ctx.exceptions.attribute_error) {
         Ok(default)
     } else {
@@ -628,7 +629,7 @@ impl Printer for std::io::StdoutLock<'_> {
 
 pub fn builtin_exit(exit_code_arg: OptionalArg<PyObjectRef>, vm: &VirtualMachine) -> PyResult {
     let code = exit_code_arg.unwrap_or_else(|| vm.new_int(0));
-    Err(vm.new_exception_obj(vm.ctx.exceptions.system_exit.clone(), vec![code])?)
+    Err(vm.new_exception(vm.ctx.exceptions.system_exit.clone(), vec![code]))
 }
 
 pub fn builtin_print(objects: Args, options: PrintOptions, vm: &VirtualMachine) -> PyResult<()> {