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Merge pull request #2805 from Mingun/untagged-tests
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Fix deserialization of empty structs and tuples in untagged enums
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@dtolnay
dtolnay committed Aug 24, 2024
2 parents 31ca16d + 7bde100 commit 9eaf7b9
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Showing 4 changed files with 621 additions and 560 deletions.
198 changes: 37 additions & 161 deletions serde/src/private/de.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1898,10 +1898,17 @@ mod content {
where
V: Visitor<'de>,
{
// Covered by tests/test_enum_untagged.rs
// with_optional_field::*
match *self.content {
Content::None => visitor.visit_none(),
Content::Some(ref v) => visitor.visit_some(ContentRefDeserializer::new(v)),
Content::Unit => visitor.visit_unit(),
// This case is necessary for formats which does not store marker of optionality of value,
// for example, JSON. When `deserialize_any` is requested from such formats, they will
// report value without using `Visitor::visit_some`, because they do not known in which
// contexts this value will be used.
// RON is example of format which preserve markers.
_ => visitor.visit_some(self),
}
}
Expand Down Expand Up @@ -1931,10 +1938,17 @@ mod content {
where
V: Visitor<'de>,
{
// Covered by tests/test_enum_untagged.rs
// newtype_struct
match *self.content {
Content::Newtype(ref v) => {
visitor.visit_newtype_struct(ContentRefDeserializer::new(v))
}
// This case is necessary for formats which does not store marker of a newtype,
// for example, JSON. When `deserialize_any` is requested from such formats, they will
// report value without using `Visitor::visit_newtype_struct`, because they do not
// known in which contexts this value will be used.
// RON is example of format which preserve markers.
_ => visitor.visit_newtype_struct(self),
}
}
Expand Down Expand Up @@ -2139,6 +2153,10 @@ mod content {
fn unit_variant(self) -> Result<(), E> {
match self.value {
Some(value) => de::Deserialize::deserialize(ContentRefDeserializer::new(value)),
// Covered by tests/test_annotations.rs
// test_partially_untagged_adjacently_tagged_enum
// Covered by tests/test_enum_untagged.rs
// newtype_enum::unit
None => Ok(()),
}
}
Expand All @@ -2148,6 +2166,11 @@ mod content {
T: de::DeserializeSeed<'de>,
{
match self.value {
// Covered by tests/test_annotations.rs
// test_partially_untagged_enum_desugared
// test_partially_untagged_enum_generic
// Covered by tests/test_enum_untagged.rs
// newtype_enum::newtype
Some(value) => seed.deserialize(ContentRefDeserializer::new(value)),
None => Err(de::Error::invalid_type(
de::Unexpected::UnitVariant,
Expand All @@ -2161,9 +2184,13 @@ mod content {
V: de::Visitor<'de>,
{
match self.value {
Some(Content::Seq(v)) => {
de::Deserializer::deserialize_any(SeqRefDeserializer::new(v), visitor)
}
// Covered by tests/test_annotations.rs
// test_partially_untagged_enum
// test_partially_untagged_enum_desugared
// Covered by tests/test_enum_untagged.rs
// newtype_enum::tuple0
// newtype_enum::tuple2
Some(Content::Seq(v)) => visit_content_seq_ref(v, visitor),
Some(other) => Err(de::Error::invalid_type(
other.unexpected(),
&"tuple variant",
Expand All @@ -2184,12 +2211,13 @@ mod content {
V: de::Visitor<'de>,
{
match self.value {
Some(Content::Map(v)) => {
de::Deserializer::deserialize_any(MapRefDeserializer::new(v), visitor)
}
Some(Content::Seq(v)) => {
de::Deserializer::deserialize_any(SeqRefDeserializer::new(v), visitor)
}
// Covered by tests/test_enum_untagged.rs
// newtype_enum::struct_from_map
Some(Content::Map(v)) => visit_content_map_ref(v, visitor),
// Covered by tests/test_enum_untagged.rs
// newtype_enum::struct_from_seq
// newtype_enum::empty_struct_from_seq
Some(Content::Seq(v)) => visit_content_seq_ref(v, visitor),
Some(other) => Err(de::Error::invalid_type(
other.unexpected(),
&"struct variant",
Expand All @@ -2202,158 +2230,6 @@ mod content {
}
}

struct SeqRefDeserializer<'a, 'de: 'a, E>
where
E: de::Error,
{
iter: <&'a [Content<'de>] as IntoIterator>::IntoIter,
err: PhantomData<E>,
}

impl<'a, 'de, E> SeqRefDeserializer<'a, 'de, E>
where
E: de::Error,
{
fn new(slice: &'a [Content<'de>]) -> Self {
SeqRefDeserializer {
iter: slice.iter(),
err: PhantomData,
}
}
}

impl<'de, 'a, E> de::Deserializer<'de> for SeqRefDeserializer<'a, 'de, E>
where
E: de::Error,
{
type Error = E;

#[inline]
fn deserialize_any<V>(mut self, visitor: V) -> Result<V::Value, Self::Error>
where
V: de::Visitor<'de>,
{
let len = self.iter.len();
if len == 0 {
visitor.visit_unit()
} else {
let ret = tri!(visitor.visit_seq(&mut self));
let remaining = self.iter.len();
if remaining == 0 {
Ok(ret)
} else {
Err(de::Error::invalid_length(len, &"fewer elements in array"))
}
}
}

forward_to_deserialize_any! {
bool i8 i16 i32 i64 i128 u8 u16 u32 u64 u128 f32 f64 char str string
bytes byte_buf option unit unit_struct newtype_struct seq tuple
tuple_struct map struct enum identifier ignored_any
}
}

impl<'de, 'a, E> de::SeqAccess<'de> for SeqRefDeserializer<'a, 'de, E>
where
E: de::Error,
{
type Error = E;

fn next_element_seed<T>(&mut self, seed: T) -> Result<Option<T::Value>, Self::Error>
where
T: de::DeserializeSeed<'de>,
{
match self.iter.next() {
Some(value) => seed
.deserialize(ContentRefDeserializer::new(value))
.map(Some),
None => Ok(None),
}
}

fn size_hint(&self) -> Option<usize> {
size_hint::from_bounds(&self.iter)
}
}

struct MapRefDeserializer<'a, 'de: 'a, E>
where
E: de::Error,
{
iter: <&'a [(Content<'de>, Content<'de>)] as IntoIterator>::IntoIter,
value: Option<&'a Content<'de>>,
err: PhantomData<E>,
}

impl<'a, 'de, E> MapRefDeserializer<'a, 'de, E>
where
E: de::Error,
{
fn new(map: &'a [(Content<'de>, Content<'de>)]) -> Self {
MapRefDeserializer {
iter: map.iter(),
value: None,
err: PhantomData,
}
}
}

impl<'de, 'a, E> de::MapAccess<'de> for MapRefDeserializer<'a, 'de, E>
where
E: de::Error,
{
type Error = E;

fn next_key_seed<T>(&mut self, seed: T) -> Result<Option<T::Value>, Self::Error>
where
T: de::DeserializeSeed<'de>,
{
match self.iter.next() {
Some((key, value)) => {
self.value = Some(value);
seed.deserialize(ContentRefDeserializer::new(key)).map(Some)
}
None => Ok(None),
}
}

fn next_value_seed<T>(&mut self, seed: T) -> Result<T::Value, Self::Error>
where
T: de::DeserializeSeed<'de>,
{
match self.value.take() {
Some(value) => seed.deserialize(ContentRefDeserializer::new(value)),
None => Err(de::Error::custom("value is missing")),
}
}

fn size_hint(&self) -> Option<usize> {
size_hint::from_bounds(&self.iter)
}
}

impl<'de, 'a, E> de::Deserializer<'de> for MapRefDeserializer<'a, 'de, E>
where
E: de::Error,
{
type Error = E;

#[inline]
fn deserialize_any<V>(self, visitor: V) -> Result<V::Value, Self::Error>
where
V: de::Visitor<'de>,
{
visitor.visit_map(self)
}

forward_to_deserialize_any! {
bool i8 i16 i32 i64 i128 u8 u16 u32 u64 u128 f32 f64 char str string
bytes byte_buf option unit unit_struct newtype_struct seq tuple
tuple_struct map struct enum identifier ignored_any
}
}

impl<'de, E> de::IntoDeserializer<'de, E> for ContentDeserializer<'de, E>
where
E: de::Error,
Expand Down
47 changes: 0 additions & 47 deletions test_suite/tests/test_annotations.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -1895,18 +1895,6 @@ fn test_expecting_message_externally_tagged_enum() {
);
}

#[test]
fn test_expecting_message_untagged_tagged_enum() {
#[derive(Deserialize)]
#[serde(untagged)]
#[serde(expecting = "something strange...")]
enum Enum {
Untagged,
}

assert_de_tokens_error::<Enum>(&[Token::Str("Untagged")], "something strange...");
}

#[test]
fn test_expecting_message_identifier_enum() {
#[derive(Deserialize)]
Expand Down Expand Up @@ -2958,41 +2946,6 @@ mod flatten {
mod untagged {
use super::*;

#[test]
fn straightforward() {
#[derive(Serialize, Deserialize, PartialEq, Debug)]
#[serde(untagged)]
enum Data {
A {
a: i32,
#[serde(flatten)]
flat: Flat,
},
}

#[derive(Serialize, Deserialize, PartialEq, Debug)]
struct Flat {
b: i32,
}

let data = Data::A {
a: 0,
flat: Flat { b: 0 },
};

assert_tokens(
&data,
&[
Token::Map { len: None },
Token::Str("a"),
Token::I32(0),
Token::Str("b"),
Token::I32(0),
Token::MapEnd,
],
);
}

#[derive(Debug, PartialEq, Serialize, Deserialize)]
struct Flatten {
#[serde(flatten)]
Expand Down
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