Release 1.0.52

serde/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde"
-version = "1.0.51" # remember to update html_root_url
+version = "1.0.52" # remember to update html_root_url
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "A generic serialization/deserialization framework"

serde/src/lib.rs

@@ -79,7 +79,7 @@
 ////////////////////////////////////////////////////////////////////////////////
 
 // Serde types in rustdoc of other crates get linked to here.
-#![doc(html_root_url = "https://docs.rs/serde/1.0.51")]
+#![doc(html_root_url = "https://docs.rs/serde/1.0.52")]
 // Support using Serde without the standard library!
 #![cfg_attr(not(feature = "std"), no_std)]
 // Unstable functionality only if the user asks for it. For tracking and

serde_derive/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde_derive"
-version = "1.0.51" # remember to update html_root_url
+version = "1.0.52" # remember to update html_root_url
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "Macros 1.1 implementation of #[derive(Serialize, Deserialize)]"

serde_derive/src/bound.rs

@@ -65,6 +65,28 @@ pub fn with_where_predicates_from_fields(
     generics
 }
 
+pub fn with_where_predicates_from_variants(
+    cont: &Container,
+    generics: &syn::Generics,
+    from_variant: fn(&attr::Variant) -> Option<&[syn::WherePredicate]>,
+) -> syn::Generics {
+    let variants = match cont.data {
+        Data::Enum(ref variants) => variants,
+        Data::Struct(_, _) => {
+            return generics.clone();
+        }
+    };
+
+    let predicates = variants
+        .iter()
+        .flat_map(|variant| from_variant(&variant.attrs))
+        .flat_map(|predicates| predicates.to_vec());
+
+    let mut generics = generics.clone();
+    generics.make_where_clause().predicates.extend(predicates);
+    generics
+}
+
 // Puts the given bound on any generic type parameters that are used in fields
 // for which filter returns true.
 //

serde_derive/src/de.rs

@@ -163,6 +163,9 @@ fn build_generics(cont: &Container, borrowed: &BorrowedLifetimes) -> syn::Generi
 
     let generics = bound::with_where_predicates_from_fields(cont, &generics, attr::Field::de_bound);
 
+    let generics =
+        bound::with_where_predicates_from_variants(cont, &generics, attr::Variant::de_bound);
+
     match cont.attrs.de_bound() {
         Some(predicates) => bound::with_where_predicates(&generics, predicates),
         None => {
@@ -201,6 +204,7 @@ fn needs_deserialize_bound(field: &attr::Field, variant: Option<&attr::Variant>)
     !field.skip_deserializing() && field.deserialize_with().is_none() && field.de_bound().is_none()
         && variant.map_or(true, |variant| {
             !variant.skip_deserializing() && variant.deserialize_with().is_none()
+                && variant.de_bound().is_none()
         })
 }
 
@@ -423,7 +427,9 @@ fn deserialize_tuple(
         None
     };
 
-    let visit_seq = Stmts(deserialize_seq(&type_path, params, fields, false, cattrs));
+    let visit_seq = Stmts(deserialize_seq(
+        &type_path, params, fields, false, cattrs, &expecting,
+    ));
 
     let visitor_expr = quote! {
         __Visitor {
@@ -507,7 +513,7 @@ fn deserialize_tuple_in_place(
         None
     };
 
-    let visit_seq = Stmts(deserialize_seq_in_place(params, fields, cattrs));
+    let visit_seq = Stmts(deserialize_seq_in_place(params, fields, cattrs, &expecting));
 
     let visitor_expr = quote! {
         __Visitor {
@@ -573,6 +579,7 @@ fn deserialize_seq(
     fields: &[Field],
     is_struct: bool,
     cattrs: &attr::Container,
+    expecting: &str,
 ) -> Fragment {
     let vars = (0..fields.len()).map(field_i as fn(_) -> _);
 
@@ -582,7 +589,11 @@ fn deserialize_seq(
         .iter()
         .filter(|field| !field.attrs.skip_deserializing())
         .count();
-    let expecting = format!("tuple of {} elements", deserialized_count);
+    let expecting = if deserialized_count == 1 {
+        format!("{} with 1 element", expecting)
+    } else {
+        format!("{} with {} elements", expecting, deserialized_count)
+    };
 
     let mut index_in_seq = 0_usize;
     let let_values = vars.clone().zip(fields).map(|(var, field)| {
@@ -667,6 +678,7 @@ fn deserialize_seq_in_place(
     params: &Parameters,
     fields: &[Field],
     cattrs: &attr::Container,
+    expecting: &str,
 ) -> Fragment {
     let vars = (0..fields.len()).map(field_i as fn(_) -> _);
 
@@ -676,7 +688,11 @@ fn deserialize_seq_in_place(
         .iter()
         .filter(|field| !field.attrs.skip_deserializing())
         .count();
-    let expecting = format!("tuple of {} elements", deserialized_count);
+    let expecting = if deserialized_count == 1 {
+        format!("{} with 1 element", expecting)
+    } else {
+        format!("{} with {} elements", expecting, deserialized_count)
+    };
 
     let mut index_in_seq = 0usize;
     let write_values = vars.clone()
@@ -848,7 +864,7 @@ fn deserialize_struct(
         None => format!("struct {}", params.type_name()),
     };
 
-    let visit_seq = Stmts(deserialize_seq(&type_path, params, fields, true, cattrs));
+    let visit_seq = Stmts(deserialize_seq(&type_path, params, fields, true, cattrs, &expecting));
 
     let (field_visitor, fields_stmt, visit_map) = if cattrs.has_flatten() {
         deserialize_struct_as_map_visitor(&type_path, params, fields, cattrs)
@@ -987,7 +1003,7 @@ fn deserialize_struct_in_place(
         None => format!("struct {}", params.type_name()),
     };
 
-    let visit_seq = Stmts(deserialize_seq_in_place(params, fields, cattrs));
+    let visit_seq = Stmts(deserialize_seq_in_place(params, fields, cattrs, &expecting));
 
     let (field_visitor, fields_stmt, visit_map) =
         deserialize_struct_as_struct_in_place_visitor(params, fields, cattrs);

serde_derive/src/internals/attr.rs

@@ -527,6 +527,8 @@ pub struct Variant {
     ser_renamed: bool,
     de_renamed: bool,
     rename_all: RenameRule,
+    ser_bound: Option<Vec<syn::WherePredicate>>,
+    de_bound: Option<Vec<syn::WherePredicate>>,
     skip_deserializing: bool,
     skip_serializing: bool,
     other: bool,
@@ -542,6 +544,8 @@ impl Variant {
         let mut skip_deserializing = BoolAttr::none(cx, "skip_deserializing");
         let mut skip_serializing = BoolAttr::none(cx, "skip_serializing");
         let mut rename_all = Attr::none(cx, "rename_all");
+        let mut ser_bound = Attr::none(cx, "bound");
+        let mut de_bound = Attr::none(cx, "bound");
         let mut other = BoolAttr::none(cx, "other");
         let mut serialize_with = Attr::none(cx, "serialize_with");
         let mut deserialize_with = Attr::none(cx, "deserialize_with");
@@ -601,6 +605,24 @@ impl Variant {
                         other.set_true();
                     }
 
+                    // Parse `#[serde(bound = "D: Serialize")]`
+                    Meta(NameValue(ref m)) if m.ident == "bound" => {
+                        if let Ok(where_predicates) =
+                            parse_lit_into_where(cx, m.ident.as_ref(), m.ident.as_ref(), &m.lit)
+                        {
+                            ser_bound.set(where_predicates.clone());
+                            de_bound.set(where_predicates);
+                        }
+                    }
+
+                    // Parse `#[serde(bound(serialize = "D: Serialize", deserialize = "D: Deserialize"))]`
+                    Meta(List(ref m)) if m.ident == "bound" => {
+                        if let Ok((ser, de)) = get_where_predicates(cx, &m.nested) {
+                            ser_bound.set_opt(ser);
+                            de_bound.set_opt(de);
+                        }
+                    }
+
                     // Parse `#[serde(with = "...")]`
                     Meta(NameValue(ref m)) if m.ident == "with" => {
                         if let Ok(path) = parse_lit_into_expr_path(cx, m.ident.as_ref(), &m.lit) {
@@ -669,6 +691,8 @@ impl Variant {
             ser_renamed: ser_renamed,
             de_renamed: de_renamed,
             rename_all: rename_all.get().unwrap_or(RenameRule::None),
+            ser_bound: ser_bound.get(),
+            de_bound: de_bound.get(),
             skip_deserializing: skip_deserializing.get(),
             skip_serializing: skip_serializing.get(),
             other: other.get(),
@@ -695,6 +719,14 @@ impl Variant {
         &self.rename_all
     }
 
+    pub fn ser_bound(&self) -> Option<&[syn::WherePredicate]> {
+        self.ser_bound.as_ref().map(|vec| &vec[..])
+    }
+
+    pub fn de_bound(&self) -> Option<&[syn::WherePredicate]> {
+        self.de_bound.as_ref().map(|vec| &vec[..])
+    }
+
     pub fn skip_deserializing(&self) -> bool {
         self.skip_deserializing
     }
@@ -1006,7 +1038,7 @@ impl Field {
                 };
                 deserialize_with.set_if_none(expr);
             }
-        } else if is_rptr(&field.ty, is_str) || is_rptr(&field.ty, is_slice_u8) {
+        } else if is_implicitly_borrowed(&field.ty) {
             // Types &str and &[u8] are always implicitly borrowed. No need for
             // a #[serde(borrow)].
             collect_lifetimes(&field.ty, &mut borrowed_lifetimes);
@@ -1268,6 +1300,14 @@ fn parse_lit_into_lifetimes(
     Err(())
 }
 
+fn is_implicitly_borrowed(ty: &syn::Type) -> bool {
+    is_implicitly_borrowed_reference(ty) || is_option(ty, is_implicitly_borrowed_reference)
+}
+
+fn is_implicitly_borrowed_reference(ty: &syn::Type) -> bool {
+    is_reference(ty, is_str) || is_reference(ty, is_slice_u8)
+}
+
 // Whether the type looks like it might be `std::borrow::Cow<T>` where elem="T".
 // This can have false negatives and false positives.
 //
@@ -1315,6 +1355,31 @@ fn is_cow(ty: &syn::Type, elem: fn(&syn::Type) -> bool) -> bool {
     }
 }
 
+fn is_option(ty: &syn::Type, elem: fn(&syn::Type) -> bool) -> bool {
+    let path = match *ty {
+        syn::Type::Path(ref ty) => &ty.path,
+        _ => {
+            return false;
+        }
+    };
+    let seg = match path.segments.last() {
+        Some(seg) => seg.into_value(),
+        None => {
+            return false;
+        }
+    };
+    let args = match seg.arguments {
+        syn::PathArguments::AngleBracketed(ref bracketed) => &bracketed.args,
+        _ => {
+            return false;
+        }
+    };
+    seg.ident == "Option" && args.len() == 1 && match args[0] {
+        syn::GenericArgument::Type(ref arg) => elem(arg),
+        _ => false,
+    }
+}
+
 // Whether the type looks like it might be `&T` where elem="T". This can have
 // false negatives and false positives.
 //
@@ -1335,7 +1400,7 @@ fn is_cow(ty: &syn::Type, elem: fn(&syn::Type) -> bool) -> bool {
 //     struct S<'a> {
 //         r: &'a str,
 //     }
-fn is_rptr(ty: &syn::Type, elem: fn(&syn::Type) -> bool) -> bool {
+fn is_reference(ty: &syn::Type, elem: fn(&syn::Type) -> bool) -> bool {
     match *ty {
         syn::Type::Reference(ref ty) => ty.mutability.is_none() && elem(&ty.elem),
         _ => false,

serde_derive/src/lib.rs

@@ -22,7 +22,7 @@
 //!
 //! [https://serde.rs/derive.html]: https://serde.rs/derive.html
 
-#![doc(html_root_url = "https://docs.rs/serde_derive/1.0.51")]
+#![doc(html_root_url = "https://docs.rs/serde_derive/1.0.52")]
 #![cfg_attr(feature = "cargo-clippy", deny(clippy, clippy_pedantic))]
 // Whitelisted clippy lints
 #![cfg_attr(

serde_derive/src/ser.rs

@@ -138,6 +138,9 @@ fn build_generics(cont: &Container) -> syn::Generics {
     let generics =
         bound::with_where_predicates_from_fields(cont, &generics, attr::Field::ser_bound);
 
+    let generics =
+        bound::with_where_predicates_from_variants(cont, &generics, attr::Variant::ser_bound);
+
     match cont.attrs.ser_bound() {
         Some(predicates) => bound::with_where_predicates(&generics, predicates),
         None => bound::with_bound(
@@ -158,6 +161,7 @@ fn needs_serialize_bound(field: &attr::Field, variant: Option<&attr::Variant>) -
     !field.skip_serializing() && field.serialize_with().is_none() && field.ser_bound().is_none()
         && variant.map_or(true, |variant| {
             !variant.skip_serializing() && variant.serialize_with().is_none()
+                && variant.ser_bound().is_none()
         })
 }
 
@@ -239,8 +243,25 @@ fn serialize_tuple_struct(
         serialize_tuple_struct_visitor(fields, params, false, &TupleTrait::SerializeTupleStruct);
 
     let type_name = cattrs.name().serialize_name();
-    let len = serialize_stmts.len();
-    let let_mut = mut_if(len > 0);
+
+    let mut serialized_fields = fields
+        .iter()
+        .enumerate()
+        .filter(|&(_, ref field)| !field.attrs.skip_serializing())
+        .peekable();
+
+    let let_mut = mut_if(serialized_fields.peek().is_some());
+
+    let len = serialized_fields
+        .map(|(i, field)| match field.attrs.skip_serializing_if() {
+            None => quote!(1),
+            Some(path) => {
+                let index = syn::Index { index: i as u32, span: Span::call_site() };
+                let field_expr = get_member(params, field, &Member::Unnamed(index));
+                quote!(if #path(#field_expr) { 0 } else { 1 })
+            }
+        })
+        .fold(quote!(0), |sum, expr| quote!(#sum + #expr));
 
     quote_block! {
         let #let_mut __serde_state = try!(_serde::Serializer::serialize_tuple_struct(__serializer, #type_name, #len));
@@ -739,8 +760,23 @@ fn serialize_tuple_variant(
 
     let serialize_stmts = serialize_tuple_struct_visitor(fields, params, true, &tuple_trait);
 
-    let len = serialize_stmts.len();
-    let let_mut = mut_if(len > 0);
+    let mut serialized_fields = fields
+        .iter()
+        .enumerate()
+        .filter(|&(_, ref field)| !field.attrs.skip_serializing())
+        .peekable();
+
+    let let_mut = mut_if(serialized_fields.peek().is_some());
+
+    let len = serialized_fields
+        .map(|(i, field)| match field.attrs.skip_serializing_if() {
+            None => quote!(1),
+            Some(path) => {
+                let field_expr = Ident::new(&format!("__field{}", i), Span::call_site());
+                quote!(if #path(#field_expr) { 0 } else { 1 })
+            }
+        })
+        .fold(quote!(0), |sum, expr| quote!(#sum + #expr));
 
     match context {
         TupleVariant::ExternallyTagged {
@@ -962,6 +998,7 @@ fn serialize_tuple_struct_visitor(
     fields
         .iter()
         .enumerate()
+        .filter(|&(_, ref field)| !field.attrs.skip_serializing())
         .map(|(i, field)| {
             let mut field_expr = if is_enum {
                 let id = Ident::new(&format!("__field{}", i), Span::call_site());

serde_test/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "serde_test"
-version = "1.0.51" # remember to update html_root_url
+version = "1.0.52" # remember to update html_root_url
 authors = ["Erick Tryzelaar <erick.tryzelaar@gmail.com>", "David Tolnay <dtolnay@gmail.com>"]
 license = "MIT/Apache-2.0"
 description = "Token De/Serializer for testing De/Serialize implementations"

serde_test/src/lib.rs

@@ -161,7 +161,7 @@
 //! # }
 //! ```
 
-#![doc(html_root_url = "https://docs.rs/serde_test/1.0.51")]
+#![doc(html_root_url = "https://docs.rs/serde_test/1.0.52")]
 #![cfg_attr(feature = "cargo-clippy", deny(clippy, clippy_pedantic))]
 // Whitelisted clippy lints
 #![cfg_attr(feature = "cargo-clippy", allow(float_cmp))]

test_suite/tests/test_annotations.rs

@@ -657,6 +657,44 @@ fn test_skip_serializing_struct() {
     );
 }
 
+#[derive(Debug, PartialEq, Serialize)]
+struct SkipSerializingTupleStruct<'a, B, C>(
+    &'a i8,
+    #[serde(skip_serializing)] B,
+    #[serde(skip_serializing_if = "ShouldSkip::should_skip")] C,
+)
+where
+    C: ShouldSkip;
+
+#[test]
+fn test_skip_serializing_tuple_struct() {
+    let a = 1;
+    assert_ser_tokens(
+        &SkipSerializingTupleStruct(&a, 2, 3),
+        &[
+            Token::TupleStruct {
+                name: "SkipSerializingTupleStruct",
+                len: 2,
+            },
+            Token::I8(1),
+            Token::I32(3),
+            Token::TupleStructEnd,
+        ],
+    );
+
+    assert_ser_tokens(
+        &SkipSerializingTupleStruct(&a, 2, 123),
+        &[
+            Token::TupleStruct {
+                name: "SkipSerializingTupleStruct",
+                len: 1,
+            },
+            Token::I8(1),
+            Token::TupleStructEnd,
+        ],
+    );
+}
+
 #[derive(Debug, PartialEq, Serialize, Deserialize)]
 struct SkipStruct<B> {
     a: i8,
@@ -705,6 +743,11 @@ where
         #[serde(skip_serializing_if = "ShouldSkip::should_skip")]
         c: C,
     },
+    Tuple(
+        &'a i8,
+        #[serde(skip_serializing)] B,
+        #[serde(skip_serializing_if = "ShouldSkip::should_skip")] C,
+    ),
 }
 
 #[test]
@@ -743,6 +786,33 @@ fn test_skip_serializing_enum() {
             Token::StructVariantEnd,
         ],
     );
+
+    assert_ser_tokens(
+        &SkipSerializingEnum::Tuple(&a, 2, 3),
+        &[
+            Token::TupleVariant {
+                name: "SkipSerializingEnum",
+                variant: "Tuple",
+                len: 2,
+            },
+            Token::I8(1),
+            Token::I32(3),
+            Token::TupleVariantEnd,
+        ],
+    );
+
+    assert_ser_tokens(
+        &SkipSerializingEnum::Tuple(&a, 2, 123),
+        &[
+            Token::TupleVariant {
+                name: "SkipSerializingEnum",
+                variant: "Tuple",
+                len: 1,
+            },
+            Token::I8(1),
+            Token::TupleVariantEnd,
+        ],
+    );
 }
 
 #[derive(Debug, PartialEq)]
@@ -1230,7 +1300,7 @@ fn test_invalid_length_enum() {
             Token::I32(1),
             Token::TupleVariantEnd,
         ],
-        "invalid length 1, expected tuple of 3 elements",
+        "invalid length 1, expected tuple variant InvalidLengthEnum::A with 3 elements",
     );
     assert_de_tokens_error::<InvalidLengthEnum>(
         &[
@@ -1242,7 +1312,7 @@ fn test_invalid_length_enum() {
             Token::I32(1),
             Token::TupleVariantEnd,
         ],
-        "invalid length 1, expected tuple of 2 elements",
+        "invalid length 1, expected tuple variant InvalidLengthEnum::B with 2 elements",
     );
 }
 

test_suite/tests/test_gen.rs

@@ -216,6 +216,42 @@ fn test_gen() {
     }
     assert::<WithTraits2<X, X>>();
 
+    #[derive(Serialize, Deserialize)]
+    #[serde(bound = "D: SerializeWith + DeserializeWith")]
+    enum VariantWithTraits1<D, E> {
+        #[serde(
+            serialize_with = "SerializeWith::serialize_with",
+            deserialize_with = "DeserializeWith::deserialize_with"
+        )]
+        D(D),
+        #[serde(
+            serialize_with = "SerializeWith::serialize_with",
+            deserialize_with = "DeserializeWith::deserialize_with",
+            bound = "E: SerializeWith + DeserializeWith"
+        )]
+        E(E),
+    }
+    assert::<VariantWithTraits1<X, X>>();
+
+    #[derive(Serialize, Deserialize)]
+    #[serde(bound(serialize = "D: SerializeWith", deserialize = "D: DeserializeWith"))]
+    enum VariantWithTraits2<D, E> {
+        #[serde(
+            serialize_with = "SerializeWith::serialize_with",
+            deserialize_with = "DeserializeWith::deserialize_with"
+        )]
+        D(D),
+        #[serde(
+            serialize_with = "SerializeWith::serialize_with", bound(serialize = "E: SerializeWith")
+        )]
+        #[serde(
+            deserialize_with = "DeserializeWith::deserialize_with",
+            bound(deserialize = "E: DeserializeWith")
+        )]
+        E(E),
+    }
+    assert::<VariantWithTraits2<X, X>>();
+
     #[derive(Serialize, Deserialize)]
     struct CowStr<'a>(Cow<'a, str>);
     assert::<CowStr>();
@@ -602,6 +638,11 @@ fn test_gen() {
     }
 
     assert::<SkippedVariant<X>>();
+
+    #[derive(Deserialize)]
+    struct ImpliciltyBorrowedOption<'a> {
+        option: std::option::Option<&'a str>,
+    }
 }
 
 //////////////////////////////////////////////////////////////////////////