Merge #2796

2796: Forward cfgs on pyclass fields to the method defs r=davidhewitt a=mejrs

With this and the cfg_attr PR, I don't need cfg_eval at all anymore :)


- [x] needs some more tests

Co-authored-by: mejrs <>

newsfragments/2796.changed.md

@@ -0,0 +1 @@
+Mixing cfgs and pyo3 attributes on struct fields will now work

pyo3-macros-backend/src/pymethod.rs

@@ -519,7 +519,15 @@ pub fn impl_py_setter_def(
         }
     };
 
+    let mut cfg_attrs = TokenStream::new();
+    if let PropertyType::Descriptor { field, .. } = &property_type {
+        for attr in field.attrs.iter().filter(|attr| attr.path.is_ident("cfg")) {
+            attr.to_tokens(&mut cfg_attrs);
+        }
+    }
+
     let associated_method = quote! {
+        #cfg_attrs
         unsafe fn #wrapper_ident(
             _py: _pyo3::Python<'_>,
             _slf: *mut _pyo3::ffi::PyObject,
@@ -538,6 +546,7 @@ pub fn impl_py_setter_def(
     };
 
     let method_def = quote! {
+        #cfg_attrs
         _pyo3::class::PyMethodDefType::Setter({
             #deprecations
             _pyo3::class::PySetterDef::new(
@@ -653,7 +662,15 @@ pub fn impl_py_getter_def(
         }
     };
 
+    let mut cfg_attrs = TokenStream::new();
+    if let PropertyType::Descriptor { field, .. } = &property_type {
+        for attr in field.attrs.iter().filter(|attr| attr.path.is_ident("cfg")) {
+            attr.to_tokens(&mut cfg_attrs);
+        }
+    }
+
     let associated_method = quote! {
+        #cfg_attrs
         unsafe fn #wrapper_ident(
             _py: _pyo3::Python<'_>,
             _slf: *mut _pyo3::ffi::PyObject
@@ -665,6 +682,7 @@ pub fn impl_py_getter_def(
     };
 
     let method_def = quote! {
+        #cfg_attrs
         _pyo3::class::PyMethodDefType::Getter({
             #deprecations
             _pyo3::class::PyGetterDef::new(

src/test_hygiene/pyclass.rs

@@ -34,3 +34,28 @@ pub struct Bar {
 pub enum Enum {
     Var0,
 }
+
+#[crate::pyclass]
+#[pyo3(crate = "crate")]
+pub struct Foo3 {
+    #[pyo3(get, set)]
+    #[cfg(FALSE)]
+    field: i32,
+
+    #[pyo3(get, set)]
+    #[cfg(not(FALSE))]
+    field: u32,
+}
+
+#[crate::pyclass]
+#[pyo3(crate = "crate")]
+pub struct Foo4 {
+    #[pyo3(get, set)]
+    #[cfg(FALSE)]
+    #[cfg(not(FALSE))]
+    field: i32,
+
+    #[pyo3(get, set)]
+    #[cfg(any(not(FALSE)))]
+    field: u32,
+}

tests/test_field_cfg.rs

@@ -0,0 +1,24 @@
+#![cfg(feature = "macros")]
+
+use pyo3::prelude::*;
+
+#[pyclass]
+struct CfgClass {
+    #[pyo3(get, set)]
+    #[cfg(any())]
+    pub a: u32,
+    #[pyo3(get, set)]
+    #[cfg(all())]
+    pub b: u32,
+}
+
+#[test]
+fn test_cfg() {
+    Python::with_gil(|py| {
+        let cfg = CfgClass { b: 3 };
+        let py_cfg = Py::new(py, cfg).unwrap();
+        assert!(py_cfg.as_ref(py).getattr("a").is_err());
+        let b: u32 = py_cfg.as_ref(py).getattr("b").unwrap().extract().unwrap();
+        assert_eq!(b, 3);
+    });
+}