CHANGELOG.md

@@ -1,5 +1,10 @@
 # Changelog
 
+## v0.14.2 (October 26, 2022)
+
+- Derived impls of `FromMeta` will now error on literals, rather than silently ignoring them. [#193](https://github.com/TedDriggs/darling/pull/193)
+- Don't include property paths in compile errors when spans are available. [#203](https://github.com/TedDriggs/darling/pull/203)
+
 ## v0.14.1 (April 28, 2022)
 
 - Fix a bug where using a trait that accepts `#[darling(attributes(...))]` without specifying any attributes would emit code that did not compile. [#183](https://github.com/TedDriggs/darling/issues/183)

Cargo.toml

@@ -1,9 +1,9 @@
 [package]
 name = "darling"
-version = "0.14.1"
+version = "0.14.2"
 authors = ["Ted Driggs <ted.driggs@outlook.com>"]
 repository = "https://github.com/TedDriggs/darling"
-documentation = "https://docs.rs/darling/0.14.1"
+documentation = "https://docs.rs/darling/0.14.2"
 description = """
 A proc-macro library for reading attributes into structs when
 implementing custom derives.
@@ -17,8 +17,8 @@ exclude = ["/.travis.yml", "/publish.sh", "/.github/**"]
 maintenance = { status = "actively-developed" }
 
 [dependencies]
-darling_core = { version = "=0.14.1", path = "core" }
-darling_macro = { version = "=0.14.1", path = "macro" }
+darling_core = { version = "=0.14.2", path = "core" }
+darling_macro = { version = "=0.14.2", path = "macro" }
 
 [dev-dependencies]
 proc-macro2 = "1.0.37"

core/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "darling_core"
-version = "0.14.1"
+version = "0.14.2"
 authors = ["Ted Driggs <ted.driggs@outlook.com>"]
 repository = "https://github.com/TedDriggs/darling"
 description = """

core/src/codegen/variant_data.rs

@@ -58,11 +58,17 @@ impl<'a> FieldsGen<'a> {
 
         quote!(
             for __item in __items {
-                if let ::syn::NestedMeta::Meta(ref __inner) = *__item {
-                    let __name = ::darling::util::path_to_string(__inner.path());
-                    match __name.as_str() {
-                        #(#arms)*
-                        __other => { #handle_unknown }
+                match *__item {
+                    ::syn::NestedMeta::Meta(ref __inner) => {
+                        let __name = ::darling::util::path_to_string(__inner.path());
+                        match __name.as_str() {
+                            #(#arms)*
+                            __other => { #handle_unknown }
+                        }
+                    }
+                    ::syn::NestedMeta::Lit(ref __inner) => {
+                        __errors.push(::darling::Error::unsupported_format("literal")
+                            .with_span(__inner));
                     }
                 }
             }

core/src/error/mod.rs

@@ -446,7 +446,16 @@ impl From<syn::Error> for Error {
 impl From<Error> for syn::Error {
     fn from(e: Error) -> Self {
         if e.len() == 1 {
-            syn::Error::new(e.span(), e)
+            if let Some(span) = e.explicit_span() {
+                // Don't include the location path if the error has an explicit span,
+                // since it will be redundant and isn't consistent with how rustc
+                // exposes errors.
+                syn::Error::new(span, e.kind)
+            } else {
+                // If the error's span is going to be the macro call site, include
+                // the location information to try and help the user pinpoint the issue.
+                syn::Error::new(e.span(), e)
+            }
         } else {
             let mut syn_errors = e.flatten().into_iter().map(syn::Error::from);
             let mut error = syn_errors
@@ -683,10 +692,14 @@ impl Extend<Error> for Accumulator {
 
 impl Drop for Accumulator {
     fn drop(&mut self) {
-        if let Some(errors) = &mut self.0 {
-            match errors.len() {
-                0 => panic!("darling::error::Accumulator dropped without being finished"),
-                error_count => panic!("darling::error::Accumulator dropped without being finished. {} errors were lost.", error_count)
+        // don't try to panic if we are currently unwinding a panic
+        // otherwise we end up with an unhelful "thread panicked while panicking. aborting." message
+        if !std::thread::panicking() {
+            if let Some(errors) = &mut self.0 {
+                match errors.len() {
+                    0 => panic!("darling::error::Accumulator dropped without being finished"),
+                    error_count => panic!("darling::error::Accumulator dropped without being finished. {} errors were lost.", error_count)
+                }
             }
         }
     }

core/src/from_meta.rs

@@ -621,7 +621,7 @@ mod tests {
 
     #[test]
     fn unit_succeeds() {
-        let () = fm::<()>(quote!(ignore));
+        fm::<()>(quote!(ignore));
     }
 
     #[test]

macro/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "darling_macro"
-version = "0.14.1"
+version = "0.14.2"
 authors = ["Ted Driggs <ted.driggs@outlook.com>"]
 repository = "https://github.com/TedDriggs/darling"
 description = """
@@ -13,7 +13,7 @@ edition = "2018"
 [dependencies]
 quote = "1.0.18"
 syn = "1.0.91"
-darling_core = { version = "=0.14.1", path = "../core" }
+darling_core = { version = "=0.14.2", path = "../core" }
 
 [lib]
 proc-macro = true

src/lib.rs

@@ -61,7 +61,7 @@
 //! |---|---|---|
 //! |`ident`|`syn::Ident`|The identifier of the passed-in variant|
 //! |`discriminant`|`Option<syn::Expr>`|For a variant such as `Example = 2`, the `2`|
-//! |`fields`|`Option<darling::ast::Fields<__>>`|The fields associated with the variant|
+//! |`fields`|`darling::ast::Fields<T> where T: FromField`|The fields associated with the variant|
 //! |`attrs`|`Vec<syn::Attribute>`|The forwarded attributes from the passed in variant. These are controlled using the `forward_attrs` attribute.|
 
 extern crate core;

tests/from_meta.rs

@@ -0,0 +1,66 @@
+use darling::{Error, FromMeta};
+use syn::parse_quote;
+
+#[derive(Debug, FromMeta)]
+struct Meta {
+    #[darling(default)]
+    meta1: Option<String>,
+    #[darling(default)]
+    meta2: bool,
+}
+
+#[test]
+fn nested_meta_meta_value() {
+    let meta = Meta::from_list(&[parse_quote! {
+        meta1 = "thefeature"
+    }])
+    .unwrap();
+    assert_eq!(meta.meta1, Some("thefeature".to_string()));
+    assert!(!meta.meta2);
+}
+
+#[test]
+fn nested_meta_meta_bool() {
+    let meta = Meta::from_list(&[parse_quote! {
+        meta2
+    }])
+    .unwrap();
+    assert_eq!(meta.meta1, None);
+    assert!(meta.meta2);
+}
+
+#[test]
+fn nested_meta_lit_string_errors() {
+    let err = Meta::from_list(&[parse_quote! {
+        "meta2"
+    }])
+    .unwrap_err();
+    assert_eq!(
+        err.to_string(),
+        Error::unsupported_format("literal").to_string()
+    );
+}
+
+#[test]
+fn nested_meta_lit_integer_errors() {
+    let err = Meta::from_list(&[parse_quote! {
+        2
+    }])
+    .unwrap_err();
+    assert_eq!(
+        err.to_string(),
+        Error::unsupported_format("literal").to_string()
+    );
+}
+
+#[test]
+fn nested_meta_lit_bool_errors() {
+    let err = Meta::from_list(&[parse_quote! {
+        true
+    }])
+    .unwrap_err();
+    assert_eq!(
+        err.to_string(),
+        Error::unsupported_format("literal").to_string()
+    );
+}