Silence some warnings from derive(Properties) (#2266)

* silence some warnings from derive(Properties)

* for consistency preserve [#deny(..)]

* preserve some attributes on the struct def

adds a test case to check for several warnings

* add #[deny] in test cases to error instead of warning on failure

Co-authored-by: Julius Lungys <32368314+voidpumpkin@users.noreply.github.com>

packages/yew-macro/src/derive_props/builder.rs

@@ -9,13 +9,15 @@ use super::generics::{to_arguments, with_param_bounds, GenericArguments};
 use super::{DerivePropsInput, PropField};
 use proc_macro2::{Ident, Span};
 use quote::{format_ident, quote, ToTokens};
+use syn::Attribute;
 
 pub struct PropsBuilder<'a> {
     builder_name: &'a Ident,
     step_trait: &'a Ident,
     step_names: Vec<Ident>,
     props: &'a DerivePropsInput,
     wrapper_name: &'a Ident,
+    extra_attrs: &'a [Attribute],
 }
 
 impl ToTokens for PropsBuilder<'_> {
@@ -26,6 +28,7 @@ impl ToTokens for PropsBuilder<'_> {
             step_names,
             props,
             wrapper_name,
+            ..
         } = self;
 
         let DerivePropsInput {
@@ -91,13 +94,15 @@ impl<'a> PropsBuilder<'_> {
         step_trait: &'a Ident,
         props: &'a DerivePropsInput,
         wrapper_name: &'a Ident,
+        extra_attrs: &'a [Attribute],
     ) -> PropsBuilder<'a> {
         PropsBuilder {
             builder_name: name,
             step_trait,
             step_names: Self::build_step_names(step_trait, &props.prop_fields),
             props,
             wrapper_name,
+            extra_attrs,
         }
     }
 }
@@ -138,6 +143,7 @@ impl PropsBuilder<'_> {
             builder_name,
             props,
             step_names,
+            extra_attrs,
             ..
         } = self;
         let DerivePropsInput {
@@ -183,6 +189,7 @@ impl PropsBuilder<'_> {
             });
 
             token_stream.extend(quote! {
+                #( #extra_attrs )*
                 impl#impl_generics #builder_name<#current_step_arguments> #where_clause {
                     #(#optional_prop_fn)*
                     #(#required_prop_fn)*

packages/yew-macro/src/derive_props/field.rs

@@ -1,11 +1,12 @@
 use super::generics::GenericArguments;
+use super::should_preserve_attr;
 use proc_macro2::{Ident, Span};
 use quote::{format_ident, quote, quote_spanned};
 use std::cmp::{Ord, Ordering, PartialEq, PartialOrd};
 use std::convert::TryFrom;
 use syn::parse::Result;
 use syn::spanned::Spanned;
-use syn::{Error, Expr, Field, Path, Type, TypePath, Visibility};
+use syn::{Attribute, Error, Expr, Field, Path, Type, TypePath, Visibility};
 
 #[allow(clippy::large_enum_variant)]
 #[derive(PartialEq, Eq)]
@@ -22,6 +23,7 @@ pub struct PropField {
     ty: Type,
     name: Ident,
     attr: PropAttr,
+    extra_attrs: Vec<Attribute>,
 }
 
 impl PropField {
@@ -51,7 +53,7 @@ impl PropField {
     /// Used to transform the `PropWrapper` struct into `Properties`
     pub fn to_field_setter(&self) -> proc_macro2::TokenStream {
         let name = &self.name;
-        match &self.attr {
+        let setter = match &self.attr {
             PropAttr::Required { wrapped_name } => {
                 quote! {
                     #name: ::std::option::Option::unwrap(self.wrapped.#wrapped_name),
@@ -77,21 +79,29 @@ impl PropField {
                     #name: ::std::option::Option::unwrap_or_default(self.wrapped.#name),
                 }
             }
+        };
+        let extra_attrs = &self.extra_attrs;
+        quote! {
+            #( #extra_attrs )*
+            #setter
         }
     }
 
     /// Wrap all required props in `Option`
     pub fn to_field_def(&self) -> proc_macro2::TokenStream {
         let ty = &self.ty;
+        let extra_attrs = &self.extra_attrs;
         let wrapped_name = self.wrapped_name();
         match &self.attr {
             PropAttr::Option => {
                 quote! {
+                    #( #extra_attrs )*
                     #wrapped_name: #ty,
                 }
             }
             _ => {
                 quote! {
+                    #( #extra_attrs )*
                     #wrapped_name: ::std::option::Option<#ty>,
                 }
             }
@@ -101,7 +111,9 @@ impl PropField {
     /// All optional props must implement the `Default` trait
     pub fn to_default_setter(&self) -> proc_macro2::TokenStream {
         let wrapped_name = self.wrapped_name();
+        let extra_attrs = &self.extra_attrs;
         quote! {
+            #( #extra_attrs )*
             #wrapped_name: ::std::option::Option::None,
         }
     }
@@ -113,13 +125,13 @@ impl PropField {
         generic_arguments: &GenericArguments,
         vis: &Visibility,
     ) -> proc_macro2::TokenStream {
-        let Self { name, ty, attr } = self;
-        match attr {
+        let Self { name, ty, attr, .. } = self;
+        let build_fn = match attr {
             PropAttr::Required { wrapped_name } => {
                 quote! {
                     #[doc(hidden)]
-                    #vis fn #name(mut self, #name: impl ::yew::html::IntoPropValue<#ty>) -> #builder_name<#generic_arguments> {
-                        self.wrapped.#wrapped_name = ::std::option::Option::Some(#name.into_prop_value());
+                    #vis fn #name(mut self, value: impl ::yew::html::IntoPropValue<#ty>) -> #builder_name<#generic_arguments> {
+                        self.wrapped.#wrapped_name = ::std::option::Option::Some(value.into_prop_value());
                         #builder_name {
                             wrapped: self.wrapped,
                             _marker: ::std::marker::PhantomData,
@@ -130,21 +142,26 @@ impl PropField {
             PropAttr::Option => {
                 quote! {
                     #[doc(hidden)]
-                    #vis fn #name(mut self, #name: impl ::yew::html::IntoPropValue<#ty>) -> #builder_name<#generic_arguments> {
-                        self.wrapped.#name = #name.into_prop_value();
+                    #vis fn #name(mut self, value: impl ::yew::html::IntoPropValue<#ty>) -> #builder_name<#generic_arguments> {
+                        self.wrapped.#name = value.into_prop_value();
                         self
                     }
                 }
             }
             _ => {
                 quote! {
                     #[doc(hidden)]
-                    #vis fn #name(mut self, #name: impl ::yew::html::IntoPropValue<#ty>) -> #builder_name<#generic_arguments> {
-                        self.wrapped.#name = ::std::option::Option::Some(#name.into_prop_value());
+                    #vis fn #name(mut self, value: impl ::yew::html::IntoPropValue<#ty>) -> #builder_name<#generic_arguments> {
+                        self.wrapped.#name = ::std::option::Option::Some(value.into_prop_value());
                         self
                     }
                 }
             }
+        };
+        let extra_attrs = &self.extra_attrs;
+        quote! {
+            #( #extra_attrs )*
+            #build_fn
         }
     }
 
@@ -214,8 +231,16 @@ impl TryFrom<Field> for PropField {
     type Error = Error;
 
     fn try_from(field: Field) -> Result<Self> {
+        let extra_attrs = field
+            .attrs
+            .iter()
+            .filter(|a| should_preserve_attr(a))
+            .cloned()
+            .collect();
+
         Ok(PropField {
             attr: Self::attribute(&field)?,
+            extra_attrs,
             ty: field.ty,
             name: field.ident.unwrap(),
         })

packages/yew-macro/src/derive_props/mod.rs

@@ -9,14 +9,26 @@ use proc_macro2::{Ident, Span};
 use quote::{format_ident, quote, ToTokens};
 use std::convert::TryInto;
 use syn::parse::{Parse, ParseStream, Result};
-use syn::{DeriveInput, Generics, Visibility};
+use syn::{Attribute, DeriveInput, Generics, Visibility};
 use wrapper::PropsWrapper;
 
 pub struct DerivePropsInput {
     vis: Visibility,
     generics: Generics,
     props_name: Ident,
     prop_fields: Vec<PropField>,
+    preserved_attrs: Vec<Attribute>,
+}
+
+/// Some attributes on the original struct are to be preserved and added to the builder struct,
+/// in order to avoid warnings (sometimes reported as errors) in the output.
+fn should_preserve_attr(attr: &Attribute) -> bool {
+    // #[cfg(...)]: does not usually appear in macro inputs, but rust-analyzer seems to generate it sometimes.
+    //              If not preserved, results in "no-such-field" errors generating the field setter for `build`
+    // #[allow(...)]: silences warnings from clippy, such as dead_code etc.
+    // #[deny(...)]: enable additional warnings from clippy
+    let path = &attr.path;
+    path.is_ident("allow") || path.is_ident("deny") || path.is_ident("cfg")
 }
 
 impl Parse for DerivePropsInput {
@@ -42,11 +54,19 @@ impl Parse for DerivePropsInput {
             _ => unimplemented!("only structs are supported"),
         };
 
+        let preserved_attrs = input
+            .attrs
+            .iter()
+            .filter(|a| should_preserve_attr(a))
+            .cloned()
+            .collect();
+
         Ok(Self {
             vis: input.vis,
             props_name: input.ident,
             generics: input.generics,
             prop_fields,
+            preserved_attrs,
         })
     }
 }
@@ -61,13 +81,24 @@ impl ToTokens for DerivePropsInput {
 
         // The wrapper is a new struct which wraps required props in `Option`
         let wrapper_name = format_ident!("{}Wrapper", props_name, span = Span::call_site());
-        let wrapper = PropsWrapper::new(&wrapper_name, generics, &self.prop_fields);
+        let wrapper = PropsWrapper::new(
+            &wrapper_name,
+            generics,
+            &self.prop_fields,
+            &self.preserved_attrs,
+        );
         tokens.extend(wrapper.into_token_stream());
 
         // The builder will only build if all required props have been set
         let builder_name = format_ident!("{}Builder", props_name, span = Span::call_site());
         let builder_step = format_ident!("{}BuilderStep", props_name, span = Span::call_site());
-        let builder = PropsBuilder::new(&builder_name, &builder_step, self, &wrapper_name);
+        let builder = PropsBuilder::new(
+            &builder_name,
+            &builder_step,
+            self,
+            &wrapper_name,
+            &self.preserved_attrs,
+        );
         let builder_generic_args = builder.first_step_generic_args();
         tokens.extend(builder.into_token_stream());
 

packages/yew-macro/src/derive_props/wrapper.rs

@@ -1,19 +1,21 @@
 use super::PropField;
 use proc_macro2::Ident;
 use quote::{quote, ToTokens};
-use syn::Generics;
+use syn::{Attribute, Generics};
 
 pub struct PropsWrapper<'a> {
     wrapper_name: &'a Ident,
     generics: &'a Generics,
     prop_fields: &'a [PropField],
+    extra_attrs: &'a [Attribute],
 }
 
 impl ToTokens for PropsWrapper<'_> {
     fn to_tokens(&self, tokens: &mut proc_macro2::TokenStream) {
         let Self {
             generics,
             wrapper_name,
+            extra_attrs,
             ..
         } = self;
 
@@ -24,6 +26,7 @@ impl ToTokens for PropsWrapper<'_> {
         let wrapper_default_setters = self.default_setters();
 
         let wrapper = quote! {
+            #(#extra_attrs)*
             struct #wrapper_name#generics
                 #where_clause
             {
@@ -47,11 +50,13 @@ impl<'a> PropsWrapper<'_> {
         name: &'a Ident,
         generics: &'a Generics,
         prop_fields: &'a [PropField],
+        extra_attrs: &'a [Attribute],
     ) -> PropsWrapper<'a> {
         PropsWrapper {
             wrapper_name: name,
             generics,
             prop_fields,
+            extra_attrs,
         }
     }
 }

packages/yew-macro/tests/derive_props/pass.rs

@@ -251,12 +251,24 @@ mod t12 {
     }
 }
 
+#[deny(non_snake_case, dead_code)]
+mod t13 {
+    #[derive(::std::cmp::PartialEq, ::yew::Properties)]
+    #[allow(non_snake_case)] // putting this on fields directly does not work, even in normal rust
+    struct Props {
+        #[allow(dead_code)]
+        create_message: ::std::option::Option<bool>,
+        NonSnakeCase: u32,
+    }
+}
+
 mod raw_field_names {
     #[derive(::yew::Properties, ::std::cmp::PartialEq)]
     pub struct Props {
         r#true: u32,
         r#pointless_raw_name: u32,
     }
+
 }
 
 fn main() {}