Merge pull request #1015 from spinda/with-variant

implement (de)serialize_with for variants

test_suite/tests/compile-fail/with-variant/skip_de_newtype_field.rs

@@ -0,0 +1,25 @@
+// Copyright 2017 Serde Developers
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#[macro_use]
+extern crate serde_derive;
+
+#[derive(Deserialize)] //~ ERROR: proc-macro derive panicked
+//~^ HELP: variant `Newtype` cannot have both #[serde(deserialize_with)] and a field 0 marked with #[serde(skip_deserializing)]
+enum Enum {
+    #[serde(deserialize_with = "deserialize_some_newtype_variant")]
+    Newtype(#[serde(skip_deserializing)] String),
+}
+
+fn deserialize_some_newtype_variant<'de, D>(_: D) -> StdResult<String, D::Error>
+    where D: Deserializer<'de>,
+{
+    unimplemented!()
+}
+
+fn main() { }

test_suite/tests/compile-fail/with-variant/skip_de_struct_field.rs

@@ -0,0 +1,29 @@
+// Copyright 2017 Serde Developers
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#[macro_use]
+extern crate serde_derive;
+
+#[derive(Deserialize)] //~ ERROR: proc-macro derive panicked
+//~^ HELP: variant `Struct` cannot have both #[serde(deserialize_with)] and a field `f1` marked with #[serde(skip_deserializing)]
+enum Enum {
+    #[serde(deserialize_with = "deserialize_some_other_variant")]
+    Struct {
+        #[serde(skip_deserializing)]
+        f1: String,
+        f2: u8,
+    },
+}
+
+fn deserialize_some_other_variant<'de, D>(_: D) -> StdResult<(String, u8), D::Error>
+    where D: Deserializer<'de>,
+{
+    unimplemented!()
+}
+
+fn main() { }

test_suite/tests/compile-fail/with-variant/skip_de_tuple_field.rs

@@ -0,0 +1,25 @@
+// Copyright 2017 Serde Developers
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#[macro_use]
+extern crate serde_derive;
+
+#[derive(Deserialize)] //~ ERROR: proc-macro derive panicked
+//~^ HELP: variant `Tuple` cannot have both #[serde(deserialize_with)] and a field 0 marked with #[serde(skip_deserializing)]
+enum Enum {
+    #[serde(deserialize_with = "deserialize_some_other_variant")]
+    Tuple(#[serde(skip_deserializing)] String, u8),
+}
+
+fn deserialize_some_other_variant<'de, D>(_: D) -> StdResult<(String, u8), D::Error>
+    where D: Deserializer<'de>,
+{
+    unimplemented!()
+}
+
+fn main() { }

test_suite/tests/compile-fail/with-variant/skip_de_whole_variant.rs

@@ -0,0 +1,26 @@
+// Copyright 2017 Serde Developers
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#[macro_use]
+extern crate serde_derive;
+
+#[derive(Deserialize)] //~ ERROR: proc-macro derive panicked
+//~^ HELP: variant `Unit` cannot have both #[serde(deserialize_with)] and #[serde(skip_deserializing)]
+enum Enum {
+    #[serde(deserialize_with = "deserialize_some_unit_variant")]
+    #[serde(skip_deserializing)]
+    Unit,
+}
+
+fn deserialize_some_unit_variant<'de, D>(_: D) -> StdResult<(), D::Error>
+    where D: Deserializer<'de>,
+{
+    unimplemented!()
+}
+
+fn main() { }

test_suite/tests/compile-fail/with-variant/skip_ser_newtype_field.rs

@@ -0,0 +1,25 @@
+// Copyright 2017 Serde Developers
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#[macro_use]
+extern crate serde_derive;
+
+#[derive(Serialize)] //~ ERROR: proc-macro derive panicked
+//~^ HELP: variant `Newtype` cannot have both #[serde(serialize_with)] and a field 0 marked with #[serde(skip_serializing)]
+enum Enum {
+    #[serde(serialize_with = "serialize_some_newtype_variant")]
+    Newtype(#[serde(skip_serializing)] String),
+}
+
+fn serialize_some_newtype_variant<S>(_: &String) -> StdResult<S::Ok, S::Error>
+    where S: Serializer,
+{
+    unimplemented!()
+}
+
+fn main() { }

test_suite/tests/compile-fail/with-variant/skip_ser_newtype_field_if.rs

@@ -0,0 +1,27 @@
+// Copyright 2017 Serde Developers
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#[macro_use]
+extern crate serde_derive;
+
+#[derive(Serialize)] //~ ERROR: proc-macro derive panicked
+//~^ HELP: variant `Newtype` cannot have both #[serde(serialize_with)] and a field 0 marked with #[serde(skip_serializing_if)]
+enum Enum {
+    #[serde(serialize_with = "serialize_some_newtype_variant")]
+    Newtype(#[serde(skip_serializing_if = "always")] String),
+}
+
+fn serialize_some_newtype_variant<S>(_: &String) -> StdResult<S::Ok, S::Error>
+    where S: Serializer,
+{
+    unimplemented!()
+}
+
+fn always<T>(_: &T) -> bool { true }
+
+fn main() { }

test_suite/tests/compile-fail/with-variant/skip_ser_struct_field.rs

@@ -0,0 +1,29 @@
+// Copyright 2017 Serde Developers
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#[macro_use]
+extern crate serde_derive;
+
+#[derive(Serialize)] //~ ERROR: proc-macro derive panicked
+//~^ HELP: variant `Struct` cannot have both #[serde(serialize_with)] and a field `f1` marked with #[serde(skip_serializing)]
+enum Enum {
+    #[serde(serialize_with = "serialize_some_other_variant")]
+    Struct {
+        #[serde(skip_serializing)]
+        f1: String,
+        f2: u8,
+    },
+}
+
+fn serialize_some_other_variant<S>(_: &String, _: Option<&u8>, _: S) -> StdResult<S::Ok, S::Error>
+    where S: Serializer,
+{
+    unimplemented!()
+}
+
+fn main() { }

test_suite/tests/compile-fail/with-variant/skip_ser_struct_field_if.rs

@@ -0,0 +1,31 @@
+// Copyright 2017 Serde Developers
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#[macro_use]
+extern crate serde_derive;
+
+#[derive(Serialize)] //~ ERROR: proc-macro derive panicked
+//~^ HELP: variant `Struct` cannot have both #[serde(serialize_with)] and a field `f1` marked with #[serde(skip_serializing_if)]
+enum Enum {
+    #[serde(serialize_with = "serialize_some_newtype_variant")]
+    Struct {
+        #[serde(skip_serializing_if = "always")]
+        f1: String,
+        f2: u8,
+    },
+}
+
+fn serialize_some_other_variant<S>(_: &String, _: Option<&u8>, _: S) -> StdResult<S::Ok, S::Error>
+    where S: Serializer,
+{
+    unimplemented!()
+}
+
+fn always<T>(_: &T) -> bool { true }
+
+fn main() { }

test_suite/tests/compile-fail/with-variant/skip_ser_tuple_field.rs

@@ -0,0 +1,25 @@
+// Copyright 2017 Serde Developers
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#[macro_use]
+extern crate serde_derive;
+
+#[derive(Serialize)] //~ ERROR: proc-macro derive panicked
+//~^ HELP: variant `Tuple` cannot have both #[serde(serialize_with)] and a field 0 marked with #[serde(skip_serializing)]
+enum Enum {
+    #[serde(serialize_with = "serialize_some_other_variant")]
+    Tuple(#[serde(skip_serializing)] String, u8),
+}
+
+fn serialize_some_other_variant<S>(_: &String, _: Option<&u8>, _: S) -> StdResult<S::Ok, S::Error>
+    where S: Serializer,
+{
+    unimplemented!()
+}
+
+fn main() { }

test_suite/tests/compile-fail/with-variant/skip_ser_tuple_field_if.rs

@@ -0,0 +1,27 @@
+// Copyright 2017 Serde Developers
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#[macro_use]
+extern crate serde_derive;
+
+#[derive(Serialize)] //~ ERROR: proc-macro derive panicked
+//~^ HELP: variant `Tuple` cannot have both #[serde(serialize_with)] and a field 0 marked with #[serde(skip_serializing_if)]
+enum Enum {
+    #[serde(serialize_with = "serialize_some_other_variant")]
+    Tuple(#[serde(skip_serializing_if = "always")] String, u8),
+}
+
+fn serialize_some_other_variant<S>(_: &String, _: Option<&u8>, _: S) -> StdResult<S::Ok, S::Error>
+    where S: Serializer,
+{
+    unimplemented!()
+}
+
+fn always<T>(_: &T) -> bool { true }
+
+fn main() { }

test_suite/tests/compile-fail/with-variant/skip_ser_whole_variant.rs

@@ -0,0 +1,26 @@
+// Copyright 2017 Serde Developers
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#[macro_use]
+extern crate serde_derive;
+
+#[derive(Serialize)] //~ ERROR: proc-macro derive panicked
+//~^ HELP: variant `Unit` cannot have both #[serde(serialize_with)] and #[serde(skip_serializing)]
+enum Enum {
+    #[serde(serialize_with = "serialize_some_unit_variant")]
+    #[serde(skip_serializing)]
+    Unit,
+}
+
+fn serialize_some_unit_variant<S>(_: S) -> StdResult<S::Ok, S::Error>
+    where S: Serializer,
+{
+    unimplemented!()
+}
+
+fn main() { }

test_suite/tests/test_annotations.rs

@@ -11,6 +11,7 @@ extern crate serde_derive;
 
 extern crate serde;
 use self::serde::{Serialize, Serializer, Deserialize, Deserializer};
+use self::serde::de::{self, Unexpected};
 
 extern crate serde_test;
 use self::serde_test::{Token, assert_tokens, assert_ser_tokens, assert_de_tokens,
@@ -811,6 +812,145 @@ fn test_serialize_with_enum() {
     );
 }
 
+#[derive(Debug, PartialEq, Serialize, Deserialize)]
+enum WithVariant {
+    #[serde(serialize_with="serialize_unit_variant_as_i8")]
+    #[serde(deserialize_with="deserialize_i8_as_unit_variant")]
+    Unit,
+
+    #[serde(serialize_with="SerializeWith::serialize_with")]
+    #[serde(deserialize_with="DeserializeWith::deserialize_with")]
+    Newtype(i32),
+
+    #[serde(serialize_with="serialize_variant_as_string")]
+    #[serde(deserialize_with="deserialize_string_as_variant")]
+    Tuple(String, u8),
+
+    #[serde(serialize_with="serialize_variant_as_string")]
+    #[serde(deserialize_with="deserialize_string_as_variant")]
+    Struct {
+        f1: String,
+        f2: u8,
+    },
+}
+
+fn serialize_unit_variant_as_i8<S>(serializer: S) -> Result<S::Ok, S::Error>
+    where S: Serializer,
+{
+    serializer.serialize_i8(0)
+}
+
+fn deserialize_i8_as_unit_variant<'de, D>(deserializer: D) -> Result<(), D::Error>
+    where D: Deserializer<'de>,
+{
+    let n = i8::deserialize(deserializer)?;
+    match n {
+        0 => Ok(()),
+        _ => Err(de::Error::invalid_value(Unexpected::Signed(n as i64), &"0")),
+    }
+}
+
+fn serialize_variant_as_string<S>(f1: &str,
+                                  f2: &u8,
+                                  serializer: S)
+                                  -> Result<S::Ok, S::Error>
+    where S: Serializer,
+{
+    serializer.serialize_str(format!("{};{:?}", f1, f2).as_str())
+}
+
+fn deserialize_string_as_variant<'de, D>(deserializer: D) -> Result<(String, u8), D::Error>
+    where D: Deserializer<'de>,
+{
+    let s = String::deserialize(deserializer)?;
+    let mut pieces = s.split(';');
+    let f1 = match pieces.next() {
+        Some(x) => x,
+        None => return Err(de::Error::invalid_length(0, &"2")),
+    };
+    let f2 = match pieces.next() {
+        Some(x) => x,
+        None => return Err(de::Error::invalid_length(1, &"2")),
+    };
+    let f2 = match f2.parse() {
+        Ok(n) => n,
+        Err(_) => {
+            return Err(de::Error::invalid_value(Unexpected::Str(f2), &"an 8-bit signed integer"));
+        }
+    };
+    Ok((f1.into(), f2))
+}
+
+#[test]
+fn test_serialize_with_variant() {
+    assert_ser_tokens(
+        &WithVariant::Unit,
+        &[
+            Token::NewtypeVariant { name: "WithVariant", variant: "Unit" },
+            Token::I8(0),
+        ],
+    );
+
+    assert_ser_tokens(
+        &WithVariant::Newtype(123),
+        &[
+            Token::NewtypeVariant { name: "WithVariant", variant: "Newtype" },
+            Token::Bool(true),
+        ],
+    );
+
+    assert_ser_tokens(
+        &WithVariant::Tuple("hello".into(), 0),
+        &[
+            Token::NewtypeVariant { name: "WithVariant", variant: "Tuple" },
+            Token::Str("hello;0"),
+        ],
+    );
+
+    assert_ser_tokens(
+        &WithVariant::Struct { f1: "world".into(), f2: 1 },
+        &[
+            Token::NewtypeVariant { name: "WithVariant", variant: "Struct" },
+            Token::Str("world;1"),
+        ],
+    );
+}
+
+#[test]
+fn test_deserialize_with_variant() {
+    assert_de_tokens(
+        &WithVariant::Unit,
+        &[
+            Token::NewtypeVariant { name: "WithVariant", variant: "Unit" },
+            Token::I8(0),
+        ],
+    );
+
+    assert_de_tokens(
+        &WithVariant::Newtype(123),
+        &[
+            Token::NewtypeVariant { name: "WithVariant", variant: "Newtype" },
+            Token::Bool(true),
+        ],
+    );
+
+    assert_de_tokens(
+        &WithVariant::Tuple("hello".into(), 0),
+        &[
+            Token::NewtypeVariant { name: "WithVariant", variant: "Tuple" },
+            Token::Str("hello;0"),
+        ],
+    );
+
+    assert_de_tokens(
+        &WithVariant::Struct { f1: "world".into(), f2: 1 },
+        &[
+            Token::NewtypeVariant { name: "WithVariant", variant: "Struct" },
+            Token::Str("world;1"),
+        ],
+    );
+}
+
 #[derive(Debug, PartialEq, Deserialize)]
 struct DeserializeWithStruct<B>
 where

test_suite/tests/test_gen.rs

@@ -373,6 +373,124 @@ fn test_gen() {
         #[serde(with = "vis::SDef")]
         s: vis::S,
     }
+
+    #[derive(Serialize, Deserialize)]
+    enum ExternallyTaggedVariantWith {
+        #[allow(dead_code)]
+        Normal { f1: String },
+
+        #[serde(serialize_with = "ser_x")]
+        #[serde(deserialize_with = "de_x")]
+        #[allow(dead_code)]
+        Newtype(X),
+
+        #[serde(serialize_with = "serialize_some_other_variant")]
+        #[serde(deserialize_with = "deserialize_some_other_variant")]
+        #[allow(dead_code)]
+        Tuple(String, u8),
+
+        #[serde(serialize_with = "serialize_some_other_variant")]
+        #[serde(deserialize_with = "deserialize_some_other_variant")]
+        #[allow(dead_code)]
+        Struct {
+            f1: String,
+            f2: u8,
+        },
+
+        #[serde(serialize_with = "serialize_some_unit_variant")]
+        #[serde(deserialize_with = "deserialize_some_unit_variant")]
+        #[allow(dead_code)]
+        Unit,
+    }
+    assert_ser::<ExternallyTaggedVariantWith>();
+
+    #[derive(Serialize, Deserialize)]
+    #[serde(tag = "t")]
+    enum InternallyTaggedVariantWith {
+        #[allow(dead_code)]
+        Normal { f1: String },
+
+        #[serde(serialize_with = "ser_x")]
+        #[serde(deserialize_with = "de_x")]
+        #[allow(dead_code)]
+        Newtype(X),
+
+        #[serde(serialize_with = "serialize_some_other_variant")]
+        #[serde(deserialize_with = "deserialize_some_other_variant")]
+        #[allow(dead_code)]
+        Struct {
+            f1: String,
+            f2: u8,
+        },
+
+        #[serde(serialize_with = "serialize_some_unit_variant")]
+        #[serde(deserialize_with = "deserialize_some_unit_variant")]
+        #[allow(dead_code)]
+        Unit,
+    }
+    assert_ser::<InternallyTaggedVariantWith>();
+
+    #[derive(Serialize, Deserialize)]
+    #[serde(tag = "t", content = "c")]
+    enum AdjacentlyTaggedVariantWith {
+        #[allow(dead_code)]
+        Normal { f1: String },
+
+        #[serde(serialize_with = "ser_x")]
+        #[serde(deserialize_with = "de_x")]
+        #[allow(dead_code)]
+        Newtype(X),
+
+        #[serde(serialize_with = "serialize_some_other_variant")]
+        #[serde(deserialize_with = "deserialize_some_other_variant")]
+        #[allow(dead_code)]
+        Tuple(String, u8),
+
+        #[serde(serialize_with = "serialize_some_other_variant")]
+        #[serde(deserialize_with = "deserialize_some_other_variant")]
+        #[allow(dead_code)]
+        Struct {
+            f1: String,
+            f2: u8,
+        },
+
+        #[serde(serialize_with = "serialize_some_unit_variant")]
+        #[serde(deserialize_with = "deserialize_some_unit_variant")]
+        #[allow(dead_code)]
+        Unit,
+    }
+    assert_ser::<AdjacentlyTaggedVariantWith>();
+
+    #[derive(Serialize, Deserialize)]
+    #[serde(untagged)]
+    enum UntaggedVariantWith {
+        #[allow(dead_code)]
+        Normal { f1: String },
+
+        #[serde(serialize_with = "ser_x")]
+        #[serde(deserialize_with = "de_x")]
+        #[allow(dead_code)]
+        Newtype(X),
+
+        #[serde(serialize_with = "serialize_some_other_variant")]
+        #[serde(deserialize_with = "deserialize_some_other_variant")]
+        #[allow(dead_code)]
+        Tuple(String, u8),
+
+        #[serde(serialize_with = "serialize_some_other_variant")]
+        #[serde(deserialize_with = "deserialize_some_other_variant")]
+        #[allow(dead_code)]
+        Struct {
+            f1: String,
+            f2: u8,
+        },
+
+        #[serde(serialize_with = "serialize_some_unit_variant")]
+        #[serde(deserialize_with = "deserialize_some_unit_variant")]
+        #[allow(dead_code)]
+        Unit,
+    }
+    assert_ser::<UntaggedVariantWith>();
 }
 
 //////////////////////////////////////////////////////////////////////////
@@ -414,3 +532,29 @@ impl DeserializeWith for X {
         unimplemented!()
     }
 }
+
+pub fn serialize_some_unit_variant<S>(_: S) -> StdResult<S::Ok, S::Error>
+    where S: Serializer,
+{
+    unimplemented!()
+}
+
+pub fn deserialize_some_unit_variant<'de, D>(_: D) -> StdResult<(), D::Error>
+    where D: Deserializer<'de>,
+{
+    unimplemented!()
+}
+
+pub fn serialize_some_other_variant<S>(_: &str, _: &u8, _: S) -> StdResult<S::Ok, S::Error>
+    where S: Serializer,
+{
+    unimplemented!()
+}
+
+pub fn deserialize_some_other_variant<'de, D>(_: D) -> StdResult<(String, u8), D::Error>
+    where D: Deserializer<'de>,
+{
+    unimplemented!()
+}
+
+pub fn is_zero(n: &u8) -> bool { *n == 0 }