Add support for boa(rename = "") in TryFromJs derive (#3980)

* Add support for boa(rename = "") in TryFromJs derive

* Fix clippies and fmt

* Move macro test to boa_engine

Author: hansl

core/engine/tests/macros.rs

@@ -0,0 +1,36 @@
+#![allow(unused_crate_dependencies)]
+use boa_engine::value::TryFromJs;
+use boa_engine::{js_string, Context, JsResult, JsValue, Source};
+use boa_string::JsString;
+
+#[test]
+fn try_from_js_derive() {
+    #[derive(Debug, TryFromJs, Eq, PartialEq)]
+    struct TryFromJsTest {
+        a: JsString,
+        #[boa(rename = "bBB")]
+        b: i32,
+        #[boa(from_js_with = "check_tfj_called")]
+        c: i32,
+    }
+
+    fn check_tfj_called(value: &JsValue, context: &mut Context) -> JsResult<i32> {
+        let v = value.to_i32(context)?;
+        Ok(v / 2)
+    }
+
+    let mut context = Context::default();
+    let obj = context
+        .eval(Source::from_bytes(br#"({ a: "hello", bBB: 42, c: 120 })"#))
+        .unwrap();
+
+    let result = TryFromJsTest::try_from_js(&obj, &mut context).unwrap();
+    assert_eq!(
+        result,
+        TryFromJsTest {
+            a: js_string!("hello"),
+            b: 42,
+            c: 60
+        }
+    );
+}

core/macros/src/lib.rs

@@ -433,12 +433,10 @@ fn generate_conversion(fields: FieldsNamed) -> Result<proc_macro2::TokenStream,
             )]
         })?;
 
-        let name_str = format!("{name}");
         field_list.push(name.clone());
 
-        let error_str = format!("cannot get property {name_str} of value");
-
         let mut from_js_with = None;
+        let mut field_name = format!("{name}");
         if let Some(attr) = field
             .attrs
             .into_iter()
@@ -449,6 +447,10 @@ fn generate_conversion(fields: FieldsNamed) -> Result<proc_macro2::TokenStream,
                     let value = meta.value()?;
                     from_js_with = Some(value.parse::<LitStr>()?);
                     Ok(())
+                } else if meta.path.is_ident("rename") {
+                    let value = meta.value()?;
+                    field_name = value.parse::<LitStr>()?.value();
+                    Ok(())
                 } else {
                     Err(meta.error(
                         "invalid syntax in the `#[boa()]` attribute. \
@@ -460,8 +462,9 @@ fn generate_conversion(fields: FieldsNamed) -> Result<proc_macro2::TokenStream,
             .map_err(|err| vec![err])?;
         }
 
+        let error_str = format!("cannot get property {name} of value");
         final_fields.push(quote! {
-            let #name = match props.get(&::boa_engine::js_string!(#name_str).into()) {
+            let #name = match props.get(&::boa_engine::js_string!(#field_name).into()) {
                 Some(pd) => pd.value().ok_or_else(|| ::boa_engine::JsError::from(
                         ::boa_engine::JsNativeError::typ().with_message(#error_str)
                     ))?.clone().try_js_into(context)?,