Fix bytes constructor

Lib/test/test_bytes.py

@@ -209,8 +209,6 @@ class BaseBytesTest:
         except (OverflowError, MemoryError):
             pass
 
-    # TODO: RUSTPYTHON
-    @unittest.expectedFailure
     def test_constructor_exceptions(self):
         # Issue #34974: bytes and bytearray constructors replace unexpected
         # exceptions.

vm/src/bytes_inner.rs

@@ -21,6 +21,9 @@ use itertools::Itertools;
 use malachite_bigint::BigInt;
 use num_traits::ToPrimitive;
 
+const STRING_WITHOUT_ENCODING: &str = "string argument without an encoding";
+const ENCODING_WITHOUT_STRING: &str = "encoding without a string argument";
+
 #[derive(Debug, Default, Clone)]
 pub struct PyBytesInner {
     pub(super) elements: Vec<u8>,
@@ -75,6 +78,18 @@ impl ByteInnerNewOptions {
         Ok(vec![0; size].into())
     }
 
+    fn handle_object_fallback(obj: PyObjectRef, vm: &VirtualMachine) -> PyResult<PyBytesInner> {
+        match_class!(match obj {
+            i @ PyInt => {
+                Self::get_value_from_size(i, vm)
+            }
+            _s @ PyStr => Err(vm.new_type_error(STRING_WITHOUT_ENCODING.to_owned())),
+            obj => {
+                Self::get_value_from_source(obj, vm)
+            }
+        })
+    }
+
     pub fn get_bytes(self, cls: PyTypeRef, vm: &VirtualMachine) -> PyResult<PyBytesRef> {
         let inner = match (&self.source, &self.encoding, &self.errors) {
             (OptionalArg::Present(obj), OptionalArg::Missing, OptionalArg::Missing) => {
@@ -113,40 +128,48 @@ impl ByteInnerNewOptions {
     }
 
     pub fn get_bytearray_inner(self, vm: &VirtualMachine) -> PyResult<PyBytesInner> {
-        const STRING_WITHOUT_ENCODING: &str = "string argument without an encoding";
-        const ENCODING_WITHOUT_STRING: &str = "encoding without a string argument";
-
         match (self.source, self.encoding, self.errors) {
             (OptionalArg::Present(obj), OptionalArg::Missing, OptionalArg::Missing) => {
-                match_class!(match obj {
-                    i @ PyInt => {
-                        Ok(Self::get_value_from_size(i, vm)?)
+                // Try __index__ first to handle int-like objects that might raise custom exceptions
+                if let Some(index_result) = obj.try_index_opt(vm) {
+                    match index_result {
+                        Ok(index) => Self::get_value_from_size(index, vm),
+                        Err(e) => {
+                            // Only propagate non-TypeError exceptions
+                            // TypeError means the object doesn't support __index__, so fall back
+                            if e.fast_isinstance(vm.ctx.exceptions.type_error) {
+                                // Fall back to treating as buffer-like object
+                                Self::handle_object_fallback(obj, vm)
+                            } else {
+                                // Propagate other exceptions (e.g., ZeroDivisionError)
+                                Err(e)
+                            }
+                        }
                     }
-                    _s @ PyStr => Err(STRING_WITHOUT_ENCODING),
-                    obj => {
-                        Ok(Self::get_value_from_source(obj, vm)?)
-                    }
-                })
+                } else {
+                    Self::handle_object_fallback(obj, vm)
+                }
             }
             (OptionalArg::Present(obj), OptionalArg::Present(encoding), errors) => {
                 if let Ok(s) = obj.downcast::<PyStr>() {
-                    Ok(Self::get_value_from_string(s, encoding, errors, vm)?)
+                    Self::get_value_from_string(s, encoding, errors, vm)
                 } else {
-                    Err(ENCODING_WITHOUT_STRING)
+                    Err(vm.new_type_error(ENCODING_WITHOUT_STRING.to_owned()))
                 }
             }
             (OptionalArg::Missing, OptionalArg::Missing, OptionalArg::Missing) => {
                 Ok(PyBytesInner::default())
             }
-            (OptionalArg::Missing, OptionalArg::Present(_), _) => Err(ENCODING_WITHOUT_STRING),
+            (OptionalArg::Missing, OptionalArg::Present(_), _) => {
+                Err(vm.new_type_error(ENCODING_WITHOUT_STRING.to_owned()))
+            }
             (OptionalArg::Missing, _, OptionalArg::Present(_)) => {
-                Err("errors without a string argument")
+                Err(vm.new_type_error("errors without a string argument".to_owned()))
             }
             (OptionalArg::Present(_), OptionalArg::Missing, OptionalArg::Present(_)) => {
-                Err(STRING_WITHOUT_ENCODING)
+                Err(vm.new_type_error(STRING_WITHOUT_ENCODING.to_owned()))
             }
         }
-        .map_err(|e| vm.new_type_error(e.to_owned()))
     }
 }