Implement bytearray.__str__ && bytes.__str__ (#7477)

* Implement bytearray.__str__

* Implement bytes.__str__

* Turn __str__ method into slot

crates/vm/src/builtins/bytearray.rs

@@ -215,6 +215,15 @@ impl PyByteArray {
         size_of::<Self>() + self.borrow_buf().len() * size_of::<u8>()
     }
 
+    #[pyslot]
+    fn slot_str(zelf: &PyObject, vm: &VirtualMachine) -> PyResult<PyStrRef> {
+        let zelf = zelf.downcast_ref::<Self>().expect("expected bytearray");
+        PyBytesInner::warn_on_str("str() on a bytearray instance", vm)?;
+        let class_name = zelf.class().name();
+        let repr = zelf.inner().repr_with_name(&class_name, vm)?;
+        Ok(vm.ctx.new_str(repr))
+    }
+
     fn __add__(&self, other: ArgBytesLike) -> Self {
         self.inner().add(&other.borrow_buf()).into()
     }

crates/vm/src/builtins/bytes.rs

@@ -224,6 +224,13 @@ impl PyBytes {
         size_of::<Self>() + self.len() * size_of::<u8>()
     }
 
+    #[pyslot]
+    fn slot_str(zelf: &PyObject, vm: &VirtualMachine) -> PyResult<PyStrRef> {
+        let zelf = zelf.downcast_ref::<Self>().expect("expected bytes");
+        PyBytesInner::warn_on_str("str() on a bytes instance", vm)?;
+        Ok(vm.ctx.new_str(zelf.inner.repr_bytes(vm)?))
+    }
+
     fn __add__(&self, other: ArgBytesLike) -> Vec<u8> {
         self.inner.add(&other.borrow_buf())
     }

crates/vm/src/bytes_inner.rs

@@ -237,6 +237,18 @@ impl PyBytesInner {
         vm.new_overflow_error("bytes object is too large to make repr")
     }
 
+    pub(crate) fn warn_on_str(message: &'static str, vm: &VirtualMachine) -> PyResult<()> {
+        if vm.state.config.settings.bytes_warning > 0 {
+            crate::stdlib::_warnings::warn(
+                vm.ctx.exceptions.bytes_warning,
+                message.to_owned(),
+                1,
+                vm,
+            )?;
+        }
+        Ok(())
+    }
+
     pub fn repr_with_name(&self, class_name: &str, vm: &VirtualMachine) -> PyResult<String> {
         const DECORATION_LEN: isize = 2 + 3; // 2 for (), 3 for b"" => bytearray(b"")
         let escape = crate::literal::escape::AsciiEscape::new_repr(&self.elements);