wip

7 files changed, 717 insertions, 0 deletions

diff --git a/Cargo.toml b/Cargo.toml
index 102f63d..da4f3c6 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -17,9 +17,11 @@ facilitate deserializing and serializing Rust structures.
 
 [dependencies]
 rustc-serialize = { optional = true, version = "0.3.0" }
+serde = { optional = true, git = "https://github.com/alexcrichton/rust-serde", branch = "tweak-some-impls" }
 
 [features]
 default = ["rustc-serialize"]
 
 [dev-dependencies]
 rustc-serialize = "0.3"
+serde_macros = { git = "https://github.com/alexcrichton/rust-serde", branch = "tweak-some-impls" }
diff --git a/src/decoder/mod.rs b/src/decoder/mod.rs
index 675e0ca..a3cc29a 100644
--- a/src/decoder/mod.rs
+++ b/src/decoder/mod.rs
@@ -5,6 +5,7 @@ use Value;
 use self::DecodeErrorKind::*;
 
 #[cfg(feature = "rustc-serialize")] mod rustc_serialize;
+#[cfg(feature = "serde")] mod serde;
 
 /// A structure to transform TOML values into Rust values.
 ///
diff --git a/src/decoder/serde.rs b/src/decoder/serde.rs
new file mode 100644
index 0000000..6f60892
--- /dev/null
+++ b/src/decoder/serde.rs
@@ -0,0 +1,152 @@
+use serde::de;
+use Value;
+use super::{Decoder, DecodeError, DecodeErrorKind};
+
+struct DecodeValue(Value);
+struct MapVisitor<I>(I, Option<Value>);
+struct SubDecoder(Decoder);
+
+fn se2toml(err: de::value::Error, ty: &'static str) -> DecodeError {
+    match err {
+        de::value::Error::SyntaxError => de::Error::syntax_error(),
+        de::value::Error::EndOfStreamError => de::Error::end_of_stream_error(),
+        de::value::Error::MissingFieldError(s) => {
+            DecodeError {
+                field: Some(s.to_string()),
+                kind: DecodeErrorKind::ExpectedField(Some(ty)),
+            }
+        }
+    }
+}
+
+impl de::Deserializer for Decoder {
+    type Error = DecodeError;
+
+    fn visit<V>(&mut self, mut visitor: V) -> Result<V::Value, DecodeError>
+        where V: de::Visitor
+    {
+        match self.toml.take() {
+            Some(Value::String(s)) => {
+                visitor.visit_string(s).map_err(|e| se2toml(e, "string"))
+            }
+            Some(Value::Integer(i)) => {
+                visitor.visit_i64(i).map_err(|e| se2toml(e, "integer"))
+            }
+            Some(Value::Float(f)) => {
+                visitor.visit_f64(f).map_err(|e| se2toml(e, "float"))
+            }
+            Some(Value::Boolean(b)) => {
+                visitor.visit_bool(b).map_err(|e| se2toml(e, "bool"))
+            }
+            Some(Value::Datetime(s)) => {
+                visitor.visit_string(s).map_err(|e| se2toml(e, "date"))
+            }
+            Some(Value::Array(a)) => {
+                let len = a.len();
+                let iter = a.into_iter().map(DecodeValue);
+                let e = visitor.visit_seq(de::value::SeqDeserializer::new(iter,
+                                                                          len));
+                e.map_err(|e| se2toml(e, "array"))
+            }
+            Some(Value::Table(t)) => {
+                visitor.visit_map(MapVisitor(t.into_iter(), None))
+            }
+            None => Err(de::Error::end_of_stream_error()),
+        }
+    }
+
+    fn visit_option<V>(&mut self, mut visitor: V) -> Result<V::Value, DecodeError>
+        where V: de::Visitor
+    {
+        if self.toml.is_none() {
+            visitor.visit_none()
+        } else {
+            visitor.visit_some(self)
+        }
+    }
+
+    fn visit_seq<V>(&mut self, mut visitor: V) -> Result<V::Value, DecodeError>
+        where V: de::Visitor,
+    {
+        if self.toml.is_none() {
+            let iter = None::<i32>.into_iter();
+            let e = visitor.visit_seq(de::value::SeqDeserializer::new(iter, 0));
+            e.map_err(|e| se2toml(e, "array"))
+        } else {
+            self.visit(visitor)
+        }
+    }
+}
+
+impl de::Error for DecodeError {
+    fn syntax_error() -> DecodeError {
+        DecodeError { field: None, kind: DecodeErrorKind::SyntaxError }
+    }
+    fn end_of_stream_error() -> DecodeError {
+        DecodeError { field: None, kind: DecodeErrorKind::EndOfStream }
+    }
+    fn missing_field_error(name: &'static str) -> DecodeError {
+        DecodeError {
+            field: Some(name.to_string()),
+            kind: DecodeErrorKind::ExpectedField(None),
+        }
+    }
+}
+
+impl de::Deserializer for SubDecoder {
+    type Error = de::value::Error;
+
+    fn visit<V>(&mut self, visitor: V) -> Result<V::Value, de::value::Error>
+        where V: de::Visitor
+    {
+        self.0.visit(visitor).map_err(|e| {
+            match e.kind {
+                DecodeErrorKind::SyntaxError => de::value::Error::SyntaxError,
+                DecodeErrorKind::EndOfStream => de::value::Error::EndOfStreamError,
+                _ => de::value::Error::SyntaxError,
+            }
+        })
+    }
+}
+
+impl de::value::ValueDeserializer for DecodeValue {
+    type Deserializer = SubDecoder;
+
+    fn into_deserializer(self) -> SubDecoder {
+        SubDecoder(Decoder::new(self.0))
+    }
+}
+
+impl<I> de::MapVisitor for MapVisitor<I>
+    where I: Iterator<Item=(String, Value)>
+{
+    type Error = DecodeError;
+
+    fn visit_key<K>(&mut self) -> Result<Option<K>, DecodeError>
+        where K: de::Deserialize
+    {
+        match self.0.next() {
+            Some((k, v)) => {
+                self.1 = Some(v);
+                de::Deserialize::deserialize(&mut Decoder::new(Value::String(k)))
+                   .map(|v| Some(v))
+            }
+            None => Ok(None),
+        }
+
+    }
+
+    fn visit_value<V>(&mut self) -> Result<V, DecodeError>
+        where V: de::Deserialize
+    {
+        match self.1.take() {
+            Some(t) => de::Deserialize::deserialize(&mut Decoder::new(t)),
+            None => Err(de::Error::end_of_stream_error())
+        }
+    }
+
+    fn end(&mut self) -> Result<(), DecodeError> {
+        Ok(())
+    }
+
+}
diff --git a/src/encoder/mod.rs b/src/encoder/mod.rs
index 21185f4..8137c33 100644
--- a/src/encoder/mod.rs
+++ b/src/encoder/mod.rs
@@ -6,6 +6,7 @@ use std::mem;
 use {Value, Table};
 
 #[cfg(feature = "rustc-serialize")] mod rustc_serialize;
+#[cfg(feature = "serde")] mod serde;
 
 /// A structure to transform Rust values into TOML values.
 ///
diff --git a/src/encoder/serde.rs b/src/encoder/serde.rs
new file mode 100644
index 0000000..87a742e
--- /dev/null
+++ b/src/encoder/serde.rs
@@ -0,0 +1,84 @@
+use serde::ser;
+use Value;
+use super::{Encoder, Error};
+
+impl ser::Serializer for Encoder {
+    type Error = Error;
+
+    fn visit_bool(&mut self, v: bool) -> Result<(), Error> {
+        self.emit_value(Value::Boolean(v))
+    }
+    fn visit_i64(&mut self, v: i64) -> Result<(), Error> {
+        self.emit_value(Value::Integer(v))
+    }
+    fn visit_u64(&mut self, v: u64) -> Result<(), Error> {
+        self.visit_i64(v as i64)
+    }
+    fn visit_f64(&mut self, v: f64) -> Result<(), Error> {
+        self.emit_value(Value::Float(v))
+    }
+    fn visit_str(&mut self, value: &str) -> Result<(), Error> {
+        self.emit_value(Value::String(value.to_string()))
+    }
+    fn visit_unit(&mut self) -> Result<(), Error> {
+        Ok(())
+    }
+    fn visit_none(&mut self) -> Result<(), Error> {
+        self.emit_none()
+    }
+    fn visit_some<V>(&mut self, value: V) -> Result<(), Error>
+        where V: ser::Serialize
+    {
+        value.serialize(self)
+    }
+    fn visit_seq<V>(&mut self, mut visitor: V) -> Result<(), Error>
+        where V: ser::SeqVisitor
+    {
+        self.seq(|me| {
+            while try!(visitor.visit(me)).is_some() {}
+            Ok(())
+        })
+    }
+    fn visit_seq_elt<T>(&mut self, value: T) -> Result<(), Error>
+        where T: ser::Serialize
+    {
+        value.serialize(self)
+    }
+    fn visit_map<V>(&mut self, mut visitor: V) -> Result<(), Error>
+        where V: ser::MapVisitor
+    {
+        self.table(|me| {
+            while try!(visitor.visit(me)).is_some() {}
+            Ok(())
+        })
+    }
+    fn visit_map_elt<K, V>(&mut self, key: K, value: V) -> Result<(), Error>
+        where K: ser::Serialize, V: ser::Serialize
+    {
+        try!(self.table_key(|me| key.serialize(me)));
+        try!(value.serialize(self));
+        Ok(())
+    }
+}
+
+impl ser::Serialize for Value {
+    fn serialize<E>(&self, e: &mut E) -> Result<(), E::Error>
+        where E: ser::Serializer
+    {
+        match *self {
+            Value::String(ref s) => e.visit_str(s),
+            Value::Integer(i) => e.visit_i64(i),
+            Value::Float(f) => e.visit_f64(f),
+            Value::Boolean(b) => e.visit_bool(b),
+            Value::Datetime(ref s) => e.visit_str(s),
+            Value::Array(ref a) => {
+                e.visit_seq(ser::impls::SeqIteratorVisitor::new(a.iter(),
+                                                                Some(a.len())))
+            }
+            Value::Table(ref t) => {
+                e.visit_map(ser::impls::MapIteratorVisitor::new(t.iter(),
+                                                                Some(t.len())))
+            }
+        }
+    }
+}
diff --git a/src/lib.rs b/src/lib.rs
index 0196fbc..81083e6 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -40,6 +40,7 @@
 #![cfg_attr(test, deny(warnings))]
 
 #[cfg(feature = "rustc-serialize")] extern crate rustc_serialize;
+#[cfg(feature = "serde")] extern crate serde;
 
 use std::collections::BTreeMap;
 use std::str::FromStr;
diff --git a/tests/serde.rs b/tests/serde.rs
new file mode 100644
index 0000000..7e3c325
--- /dev/null
+++ b/tests/serde.rs
@@ -0,0 +1,476 @@
+#![cfg(feature = "serde")]
+#![feature(custom_derive, plugin)]
+#![plugin(serde_macros)]
+
+
+extern crate serde;
+extern crate toml;
+
+use std::collections::{BTreeMap, HashSet};
+use serde::{Deserialize, Serialize, Deserializer};
+
+use toml::{Encoder, Decoder, DecodeError};
+use toml::Value;
+use toml::Value::{Table, Integer, Array, Float};
+
+macro_rules! t {
+    ($e:expr) => (match $e {
+        Ok(t) => t,
+        Err(e) => panic!("{} failed with {}", stringify!($e), e),
+    })
+}
+
+macro_rules! encode( ($t:expr) => ({
+    let mut e = Encoder::new();
+    t!($t.serialize(&mut e));
+    e.toml
+}) );
+
+macro_rules! decode( ($t:expr) => ({
+    let mut d = Decoder::new($t);
+    t!(Deserialize::deserialize(&mut d))
+}) );
+
+macro_rules! map( ($($k:ident, $v:expr),*) => ({
+    let mut _m = BTreeMap::new();
+    $(_m.insert(stringify!($k).to_string(), $v);)*
+    _m
+}) );
+
+#[test]
+fn smoke() {
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Foo { a: isize }
+
+    let v = Foo { a: 2 };
+    assert_eq!(encode!(v), map! { a, Integer(2) });
+    assert_eq!(v, decode!(Table(encode!(v))));
+}
+
+#[test]
+fn smoke_hyphen() {
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Foo { a_b: isize }
+
+    let v = Foo { a_b: 2 };
+    assert_eq!(encode!(v), map! { a_b, Integer(2) });
+    assert_eq!(v, decode!(Table(encode!(v))));
+
+    let mut m = BTreeMap::new();
+    m.insert("a-b".to_string(), Integer(2));
+    assert_eq!(v, decode!(Table(encode!(v))));
+}
+
+#[test]
+fn nested() {
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Foo { a: isize, b: Bar }
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Bar { a: String }
+
+    let v = Foo { a: 2, b: Bar { a: "test".to_string() } };
+    assert_eq!(encode!(v),
+               map! {
+                   a, Integer(2),
+                   b, Table(map! {
+                       a, Value::String("test".to_string())
+                   })
+               });
+    assert_eq!(v, decode!(Table(encode!(v))));
+}
+
+#[test]
+fn application_decode_error() {
+    #[derive(PartialEq, Debug)]
+    struct Range10(usize);
+    impl Deserialize for Range10 {
+         fn deserialize<D: Deserializer>(d: &mut D) -> Result<Range10, D::Error> {
+             let x: usize = try!(Deserialize::deserialize(d));
+             if x > 10 {
+                 Err(serde::de::Error::syntax_error())
+             } else {
+                 Ok(Range10(x))
+             }
+         }
+    }
+    let mut d_good = Decoder::new(Integer(5));
+    let mut d_bad1 = Decoder::new(Value::String("not an isize".to_string()));
+    let mut d_bad2 = Decoder::new(Integer(11));
+
+    assert_eq!(Ok(Range10(5)), Deserialize::deserialize(&mut d_good));
+
+    let err1: Result<Range10, _> = Deserialize::deserialize(&mut d_bad1);
+    assert!(err1.is_err());
+    let err2: Result<Range10, _> = Deserialize::deserialize(&mut d_bad2);
+    assert!(err2.is_err());
+}
+
+#[test]
+fn array() {
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Foo { a: Vec<isize> }
+
+    let v = Foo { a: vec![1, 2, 3, 4] };
+    assert_eq!(encode!(v),
+               map! {
+                   a, Array(vec![
+                        Integer(1),
+                        Integer(2),
+                        Integer(3),
+                        Integer(4)
+                   ])
+               });
+    assert_eq!(v, decode!(Table(encode!(v))));
+}
+
+#[test]
+fn tuple() {
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Foo { a: (isize, isize, isize, isize) }
+
+    let v = Foo { a: (1, 2, 3, 4) };
+    assert_eq!(encode!(v),
+               map! {
+                   a, Array(vec![
+                        Integer(1),
+                        Integer(2),
+                        Integer(3),
+                        Integer(4)
+                   ])
+               });
+    assert_eq!(v, decode!(Table(encode!(v))));
+}
+
+#[test]
+fn inner_structs_with_options() {
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Foo {
+        a: Option<Box<Foo>>,
+        b: Bar,
+    }
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Bar {
+        a: String,
+        b: f64,
+    }
+
+    let v = Foo {
+        a: Some(Box::new(Foo {
+            a: None,
+            b: Bar { a: "foo".to_string(), b: 4.5 },
+        })),
+        b: Bar { a: "bar".to_string(), b: 1.0 },
+    };
+    assert_eq!(encode!(v),
+               map! {
+                   a, Table(map! {
+                       b, Table(map! {
+                           a, Value::String("foo".to_string()),
+                           b, Float(4.5)
+                       })
+                   }),
+                   b, Table(map! {
+                       a, Value::String("bar".to_string()),
+                       b, Float(1.0)
+                   })
+               });
+    assert_eq!(v, decode!(Table(encode!(v))));
+}
+
+#[test]
+fn hashmap() {
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Foo {
+        map: BTreeMap<String, isize>,
+        set: HashSet<char>,
+    }
+
+    let v = Foo {
+        map: {
+            let mut m = BTreeMap::new();
+            m.insert("foo".to_string(), 10);
+            m.insert("bar".to_string(), 4);
+            m
+        },
+        set: {
+            let mut s = HashSet::new();
+            s.insert('a');
+            s
+        },
+    };
+    assert_eq!(encode!(v),
+        map! {
+            map, Table(map! {
+                foo, Integer(10),
+                bar, Integer(4)
+            }),
+            set, Array(vec![Value::String("a".to_string())])
+        }
+    );
+    assert_eq!(v, decode!(Table(encode!(v))));
+}
+
+#[test]
+fn tuple_struct() {
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Foo(isize, String, f64);
+
+    let v = Foo(1, "foo".to_string(), 4.5);
+    assert_eq!(
+        encode!(v),
+        map! {
+            _field0, Integer(1),
+            _field1, Value::String("foo".to_string()),
+            _field2, Float(4.5)
+        }
+    );
+    assert_eq!(v, decode!(Table(encode!(v))));
+}
+
+#[test]
+fn table_array() {
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Foo { a: Vec<Bar>, }
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Bar { a: isize }
+
+    let v = Foo { a: vec![Bar { a: 1 }, Bar { a: 2 }] };
+    assert_eq!(
+        encode!(v),
+        map! {
+            a, Array(vec![
+                Table(map!{ a, Integer(1) }),
+                Table(map!{ a, Integer(2) }),
+            ])
+        }
+    );
+    assert_eq!(v, decode!(Table(encode!(v))));
+}
+
+#[test]
+fn type_errors() {
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Foo { bar: isize }
+
+    let mut d = Decoder::new(Table(map! {
+        bar, Float(1.0)
+    }));
+    let a: Result<Foo, DecodeError> = Deserialize::deserialize(&mut d);
+    match a {
+        Ok(..) => panic!("should not have decoded"),
+        Err(e) => {
+            assert_eq!(format!("{}", e),
+                       "expected a value of type `integer`, but \
+                        found a value of type `float` for the key `bar`");
+        }
+    }
+}
+
+#[test]
+fn missing_errors() {
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Foo { bar: isize }
+
+    let mut d = Decoder::new(Table(map! {
+    }));
+    let a: Result<Foo, DecodeError> = Deserialize::deserialize(&mut d);
+    match a {
+        Ok(..) => panic!("should not have decoded"),
+        Err(e) => {
+            assert_eq!(format!("{}", e),
+                       "expected a value of type `integer` for the key `bar`");
+        }
+    }
+}
+
+#[test]
+fn parse_enum() {
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Foo { a: E }
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    enum E {
+        Bar(isize),
+        Baz(f64),
+        Last(Foo2),
+    }
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Foo2 {
+        test: String,
+    }
+
+    let v = Foo { a: E::Bar(10) };
+    assert_eq!(
+        encode!(v),
+        map! { a, Integer(10) }
+    );
+    assert_eq!(v, decode!(Table(encode!(v))));
+
+    let v = Foo { a: E::Baz(10.2) };
+    assert_eq!(
+        encode!(v),
+        map! { a, Float(10.2) }
+    );
+    assert_eq!(v, decode!(Table(encode!(v))));
+
+    let v = Foo { a: E::Last(Foo2 { test: "test".to_string() }) };
+    assert_eq!(
+        encode!(v),
+        map! { a, Table(map! { test, Value::String("test".to_string()) }) }
+    );
+    assert_eq!(v, decode!(Table(encode!(v))));
+}
+
+#[test]
+fn unused_fields() {
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Foo { a: isize }
+
+    let v = Foo { a: 2 };
+    let mut d = Decoder::new(Table(map! {
+        a, Integer(2),
+        b, Integer(5)
+    }));
+    assert_eq!(v, t!(Deserialize::deserialize(&mut d)));
+
+    assert_eq!(d.toml, Some(Table(map! {
+        b, Integer(5)
+    })));
+}
+
+#[test]
+fn unused_fields2() {
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Foo { a: Bar }
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Bar { a: isize }
+
+    let v = Foo { a: Bar { a: 2 } };
+    let mut d = Decoder::new(Table(map! {
+        a, Table(map! {
+            a, Integer(2),
+            b, Integer(5)
+        })
+    }));
+    assert_eq!(v, t!(Deserialize::deserialize(&mut d)));
+
+    assert_eq!(d.toml, Some(Table(map! {
+        a, Table(map! {
+            b, Integer(5)
+        })
+    })));
+}
+
+#[test]
+fn unused_fields3() {
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Foo { a: Bar }
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Bar { a: isize }
+
+    let v = Foo { a: Bar { a: 2 } };
+    let mut d = Decoder::new(Table(map! {
+        a, Table(map! {
+            a, Integer(2)
+        })
+    }));
+    assert_eq!(v, t!(Deserialize::deserialize(&mut d)));
+
+    assert_eq!(d.toml, None);
+}
+
+#[test]
+fn unused_fields4() {
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Foo { a: BTreeMap<String, String> }
+
+    let v = Foo { a: map! { a, "foo".to_string() } };
+    let mut d = Decoder::new(Table(map! {
+        a, Table(map! {
+            a, Value::String("foo".to_string())
+        })
+    }));
+    assert_eq!(v, t!(Deserialize::deserialize(&mut d)));
+
+    assert_eq!(d.toml, None);
+}
+
+#[test]
+fn unused_fields5() {
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Foo { a: Vec<String> }
+
+    let v = Foo { a: vec!["a".to_string()] };
+    let mut d = Decoder::new(Table(map! {
+        a, Array(vec![Value::String("a".to_string())])
+    }));
+    assert_eq!(v, t!(Deserialize::deserialize(&mut d)));
+
+    assert_eq!(d.toml, None);
+}
+
+#[test]
+fn unused_fields6() {
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Foo { a: Option<Vec<String>> }
+
+    let v = Foo { a: Some(vec![]) };
+    let mut d = Decoder::new(Table(map! {
+        a, Array(vec![])
+    }));
+    assert_eq!(v, t!(Deserialize::deserialize(&mut d)));
+
+    assert_eq!(d.toml, None);
+}
+
+#[test]
+fn unused_fields7() {
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Foo { a: Vec<Bar> }
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Bar { a: isize }
+
+    let v = Foo { a: vec![Bar { a: 1 }] };
+    let mut d = Decoder::new(Table(map! {
+        a, Array(vec![Table(map! {
+            a, Integer(1),
+            b, Integer(2)
+        })])
+    }));
+    assert_eq!(v, t!(Deserialize::deserialize(&mut d)));
+
+    assert_eq!(d.toml, Some(Table(map! {
+        a, Array(vec![Table(map! {
+            b, Integer(2)
+        })])
+    })));
+}
+
+#[test]
+fn empty_arrays() {
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Foo { a: Vec<Bar> }
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Bar;
+
+    let v = Foo { a: vec![] };
+    let mut d = Decoder::new(Table(map! {}));
+    assert_eq!(v, t!(Deserialize::deserialize(&mut d)));
+}
+
+#[test]
+fn empty_arrays2() {
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Foo { a: Option<Vec<Bar>> }
+    #[derive(Serialize, Deserialize, PartialEq, Debug)]
+    struct Bar;
+
+    let v = Foo { a: None };
+    let mut d = Decoder::new(Table(map! {}));
+    assert_eq!(v, t!(Deserialize::deserialize(&mut d)));
+
+    let v = Foo { a: Some(vec![]) };
+    let mut d = Decoder::new(Table(map! {
+        a, Array(vec![])
+    }));
+    assert_eq!(v, t!(Deserialize::deserialize(&mut d)));
+}