deprecate pyclass name without quotes

CHANGELOG.md

@@ -21,7 +21,6 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Add `PyAny::is_instance()` method. [#1276](https://github.com/PyO3/pyo3/pull/1276)
 - Add support for conversion between `char` and `PyString`. [#1282](https://github.com/PyO3/pyo3/pull/1282)
 - Add FFI definitions for `PyBuffer_SizeFromFormat`, `PyObject_LengthHint`, `PyObject_CallNoArgs`, `PyObject_CallOneArg`, `PyObject_CallMethodNoArgs`, `PyObject_CallMethodOneArg`, `PyObject_VectorcallDict`, and `PyObject_VectorcallMethod`. [#1287](https://github.com/PyO3/pyo3/pull/1287)
-- Allow the use of a string literal in `#[pyclass(name = "string literal")]`. [#1295](https://github.com/PyO3/pyo3/pull/1295)
 - Add section about Python::check_signals to the FAQ page of the user guide. [#1301](https://github.com/PyO3/pyo3/pull/1301)
 
 ### Changed
@@ -34,6 +33,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 - Rename `PyTypeInfo::is_instance` and `PyTypeInfo::is_exact_instance` to `PyTypeInfo::is_type_of` and `PyTypeInfo::is_exact_type_of`. [#1278](https://github.com/PyO3/pyo3/pull/1278)
 - Optimize `PyAny::call0`, `Py::call0` and `PyAny::call_method0` and `Py::call_method0` on Python 3.9 and up. [#1287](https://github.com/PyO3/pyo3/pull/1285)
 - Deprecate `Python::is_instance`, `Python::is_subclass`, `Python::release`, and `Python::xdecref`. [#1292](https://github.com/PyO3/pyo3/pull/1292)
+- Require double-quotes for pyclass name argument e.g `#[pyclass(name = "MyClass")]`. [#1303](https://github.com/PyO3/pyo3/pull/1303)
 
 ### Removed
 - Remove deprecated ffi definitions `PyUnicode_AsUnicodeCopy`, `PyUnicode_GetMax`, `_Py_CheckRecursionLimit`, `PyObject_AsCharBuffer`, `PyObject_AsReadBuffer`, `PyObject_CheckReadBuffer` and `PyObject_AsWriteBuffer`, which will be removed in Python 3.10. [#1217](https://github.com/PyO3/pyo3/pull/1217)

pyo3-derive-backend/src/pyclass.rs

@@ -15,7 +15,7 @@ use syn::{parse_quote, Expr, Token};
 /// The parsed arguments of the pyclass macro
 pub struct PyClassArgs {
     pub freelist: Option<syn::Expr>,
-    pub name: Option<syn::ExprPath>,
+    pub name: Option<syn::Ident>,
     pub flags: Vec<syn::Expr>,
     pub base: syn::TypePath,
     pub has_extends: bool,
@@ -96,15 +96,26 @@ impl PyClassArgs {
                     lit: syn::Lit::Str(lit),
                     ..
                 }) => {
-                    self.name = match lit.parse() {
+                    self.name = Some(lit.parse().map_err(|_| {
-                        Ok(name) => Some(name),
+                        syn::Error::new_spanned(
-                        Err(..) => expected!("type name (e.g., Name or \"Name\")"),
+                            lit,
-                    }
+                            "expected a single identifier in double-quotes",
+                        )
+                    })?);
                 }
                 syn::Expr::Path(exp) if exp.path.segments.len() == 1 => {
-                    self.name = Some(exp.clone());
+                    return Err(syn::Error::new_spanned(
+                        exp,
+                        format!(
+                            concat!(
+                                "since PyO3 0.13 a pyclass name should be in double-quotes, ",
+                                "e.g. \"{}\""
+                            ),
+                            exp.path.get_ident().expect("path has 1 segment")
+                        ),
+                    ));
                 }
-                _ => expected!("type name (e.g., Name or \"Name\")"),
+                _ => expected!("type name (e.g. \"Name\")"),
             },
             "extends" => match &**right {
                 syn::Expr::Path(exp) => {
@@ -271,11 +282,8 @@ fn impl_proto_inventory(cls: &syn::Ident) -> TokenStream {
     }
 }
 
-fn get_class_python_name(cls: &syn::Ident, attr: &PyClassArgs) -> TokenStream {
+fn get_class_python_name<'a>(cls: &'a syn::Ident, attr: &'a PyClassArgs) -> &'a syn::Ident {
-    match &attr.name {
+    attr.name.as_ref().unwrap_or(cls)
-        Some(name) => quote! { #name },
-        None => quote! { #cls },
-    }
 }
 
 fn impl_class(

pyo3-derive-backend/src/utils.rs

@@ -76,9 +76,9 @@ fn parse_text_signature_attr<T: Display + quote::ToTokens + ?Sized>(
     }
 }
 
-pub fn parse_text_signature_attrs<T: Display + quote::ToTokens + ?Sized>(
+pub fn parse_text_signature_attrs(
     attrs: &mut Vec<syn::Attribute>,
-    python_name: &T,
+    python_name: &syn::Ident,
 ) -> syn::Result<Option<syn::LitStr>> {
     let mut text_signature = None;
     let mut attrs_out = Vec::with_capacity(attrs.len());

tests/test_class_basics.rs

@@ -66,7 +66,7 @@ fn class_with_docstr() {
     }
 }
 
-#[pyclass(name=CustomName)]
+#[pyclass(name = "CustomName")]
 struct EmptyClass2 {}
 
 #[pymethods]
@@ -79,17 +79,12 @@ impl EmptyClass2 {
     fn bar_static() {}
 }
 
-#[pyclass(name = "CustomName")]
-struct EmptyClass3 {}
-
 #[test]
 fn custom_names() {
     let gil = Python::acquire_gil();
     let py = gil.python();
     let typeobj = py.get_type::<EmptyClass2>();
-    let typeobj2 = py.get_type::<EmptyClass3>();
     py_assert!(py, typeobj, "typeobj.__name__ == 'CustomName'");
-    py_assert!(py, typeobj2, "typeobj2.__name__ == 'CustomName'");
     py_assert!(py, typeobj, "typeobj.custom_fn.__name__ == 'custom_fn'");
     py_assert!(
         py,

tests/ui/invalid_pyclass_args.rs

@@ -9,6 +9,12 @@ struct InvalidExtends {}
 #[pyclass(name = m::MyClass)]
 struct InvalidName {}
 
+#[pyclass(name = "Custom Name")]
+struct InvalidName2 {}
+
+#[pyclass(name = CustomName)]
+struct DeprecatedName {}
+
 #[pyclass(module = my_module)]
 struct InvalidModule {}
 

tests/ui/invalid_pyclass_args.stderr

@@ -10,20 +10,32 @@ error: Expected type path (e.g., my_mod::BaseClass)
 6 | #[pyclass(extends = "PyDict")]
   |                     ^^^^^^^^
 
-error: Expected type name (e.g., Name or "Name")
+error: Expected type name (e.g. "Name")
  --> $DIR/invalid_pyclass_args.rs:9:18
   |
 9 | #[pyclass(name = m::MyClass)]
   |                  ^^^^^^^^^^
 
-error: Expected string literal (e.g., "my_mod")
+error: expected a single identifier in double-quotes
-  --> $DIR/invalid_pyclass_args.rs:12:20
+  --> $DIR/invalid_pyclass_args.rs:12:18
    |
-12 | #[pyclass(module = my_module)]
+12 | #[pyclass(name = "Custom Name")]
+   |                  ^^^^^^^^^^^^^
+
+error: since PyO3 0.13 a pyclass name should be in double-quotes, e.g. "CustomName"
+  --> $DIR/invalid_pyclass_args.rs:15:18
+   |
+15 | #[pyclass(name = CustomName)]
+   |                  ^^^^^^^^^^
+
+error: Expected string literal (e.g., "my_mod")
+  --> $DIR/invalid_pyclass_args.rs:18:20
+   |
+18 | #[pyclass(module = my_module)]
    |                    ^^^^^^^^^
 
 error: Expected one of gc/weakref/subclass/dict/unsendable
-  --> $DIR/invalid_pyclass_args.rs:15:11
+  --> $DIR/invalid_pyclass_args.rs:21:11
    |
-15 | #[pyclass(weakrev)]
+21 | #[pyclass(weakrev)]
    |           ^^^^^^^