Enforce using 'MsgPack<T>' to deserialize.

This commit enforces using 'MsgPack<T>', and not 'MsgPack<T, Foo>' or
'Compact<T>', to deserialize MsgPack-encoded data. It also simplifies
the round-trip msgpack test and removes the dev-dependency on `rmp`.

core/lib/Cargo.toml

@@ -140,4 +140,3 @@ version_check = "0.9.1"
 tokio = { version = "1", features = ["macros", "io-std"] }
 figment = { version = "0.10.17", features = ["test"] }
 pretty_assertions = "1"
-rmp = "0.8"

core/lib/src/serde/msgpack.rs

@@ -171,7 +171,7 @@ impl<T, const COMPACT: bool> MsgPack<T, COMPACT> {
     }
 }
 
-impl<'r, T: Deserialize<'r>, const COMPACT: bool> MsgPack<T, COMPACT> {
+impl<'r, T: Deserialize<'r>> MsgPack<T> {
     fn from_bytes(buf: &'r [u8]) -> Result<Self, Error> {
         rmp_serde::from_slice(buf).map(MsgPack)
     }
@@ -192,7 +192,7 @@ impl<'r, T: Deserialize<'r>, const COMPACT: bool> MsgPack<T, COMPACT> {
 }
 
 #[crate::async_trait]
-impl<'r, T: Deserialize<'r>, const COMPACT: bool> FromData<'r> for MsgPack<T, COMPACT> {
+impl<'r, T: Deserialize<'r>> FromData<'r> for MsgPack<T> {
     type Error = Error;
 
     async fn from_data(req: &'r Request<'_>, data: Data<'r>) -> Outcome<'r, Self> {
@@ -233,9 +233,7 @@ impl<'r, T: Serialize, const COMPACT: bool> Responder<'r, 'static> for MsgPack<T
 }
 
 #[crate::async_trait]
-impl<'v, T, const COMPACT: bool> form::FromFormField<'v> for MsgPack<T, COMPACT>
-    where T: Deserialize<'v> + Send
-{
+impl<'v, T: Deserialize<'v> + Send> form::FromFormField<'v> for MsgPack<T> {
     // TODO: To implement `from_value`, we need to the raw string so we can
     // decode it into bytes as opposed to a string as it won't be UTF-8.
 

core/lib/tests/msgpack_encoding.rs

@@ -1,113 +1,71 @@
 #![cfg(feature = "msgpack")]
 
+use std::borrow::Cow;
+
 use rocket::{Rocket, Build};
-use rocket::serde::msgpack::{MsgPack, Compact};
+use rocket::serde::msgpack::{self, MsgPack, Compact};
 use rocket::local::blocking::Client;
 
 #[derive(serde::Serialize, serde::Deserialize, PartialEq, Eq)]
-struct Person {
-    name: String,
+struct Person<'r> {
+    name: &'r str,
     age: u8,
     gender: Gender,
 }
 
 #[derive(serde::Serialize, serde::Deserialize, PartialEq, Eq)]
-#[serde(tag = "gender")]
 enum Gender {
     Male,
     Female,
     NonBinary,
 }
 
-#[rocket::post("/age_named", data = "<person>")]
-fn named(person: MsgPack<Person>) -> MsgPack<Person> {
-    let person = Person { age: person.age + 1, ..person.into_inner() };
-    MsgPack(person)
+#[rocket::post("/named", data = "<person>")]
+fn named(person: MsgPack<Person<'_>>) -> MsgPack<Person<'_>> {
+    person
 }
 
-#[rocket::post("/age_compact", data = "<person>")]
-fn compact(person: MsgPack<Person>) -> Compact<Person> {
-    let person = Person { age: person.age + 1, ..person.into_inner() };
-    MsgPack(person)
+#[rocket::post("/compact", data = "<person>")]
+fn compact(person: MsgPack<Person<'_>>) -> Compact<Person<'_>> {
+    MsgPack(person.into_inner())
 }
 
 fn rocket() -> Rocket<Build> {
-    rocket::build()
-        .mount("/", rocket::routes![named, compact])
+    rocket::build().mount("/", rocket::routes![named, compact])
 }
 
-fn read_string(buf: &mut rmp::decode::Bytes) -> String {
-    let mut string_buf = vec![0; 32];  // Awful but we're just testing.
-    rmp::decode::read_str(buf, &mut string_buf).unwrap().to_string()
-}
+// The object we're going to roundtrip through the API.
+const OBJECT: Person<'static> = Person {
+    name: "Cal",
+    age: 17,
+    gender: Gender::NonBinary,
+};
+
+// [ "Cal", 17, "NonBinary" ]
+const COMPACT_BYTES: &[u8] = &[
+    147, 163, 67, 97, 108, 17, 169, 78, 111, 110, 66, 105, 110, 97, 114, 121
+];
+
+// { "name": "Cal", "age": 17, "gender": "NonBinary" }
+const NAMED_BYTES: &[u8] = &[
+    131, 164, 110, 97, 109, 101, 163, 67, 97, 108, 163, 97, 103, 101, 17, 166,
+    103, 101, 110, 100, 101, 114, 169, 78, 111, 110, 66, 105, 110, 97, 114, 121
+];
 
 #[test]
-fn check_named_roundtrip() {
+fn check_roundtrip() {
     let client = Client::debug(rocket()).unwrap();
-    let person = Person {
-        name: "Cal".to_string(),
-        age: 17,
-        gender: Gender::NonBinary,
-    };
-    let response = client
-        .post("/age_named")
-        .body(rmp_serde::to_vec_named(&person).unwrap())
-        .dispatch()
-        .into_bytes()
-        .unwrap();
-    let mut bytes = rmp::decode::Bytes::new(&response);
-    assert_eq!(rmp::decode::read_map_len(&mut bytes).unwrap(), 3);
-    assert_eq!(&read_string(&mut bytes), "name");
-    assert_eq!(&read_string(&mut bytes), "Cal");
-    assert_eq!(&read_string(&mut bytes), "age");
-    assert_eq!(rmp::decode::read_int::<u8, _>(&mut bytes).unwrap(), 18);
-    assert_eq!(&read_string(&mut bytes), "gender");
-    // Enums are complicated in serde. In this test, they're encoded like this:
-    // (JSON equivalent) `{ "gender": "NonBinary" }`, where that object is itself
-    // the value of the `gender` key in the outer object. `#[serde(flatten)]`
-    // on the `gender` key in the outer object fixes this, but it prevents `rmp`
-    // from using compact mode, which would break the test.
-    assert_eq!(rmp::decode::read_map_len(&mut bytes).unwrap(), 1);
-    assert_eq!(&read_string(&mut bytes), "gender");
-    assert_eq!(&read_string(&mut bytes), "NonBinary");
+    let inputs: &[(&'static str, Cow<'static, [u8]>)] = &[
+        ("objpack", msgpack::to_vec(&OBJECT).unwrap().into()),
+        ("named bytes", NAMED_BYTES.into()),
+        ("compact bytes", COMPACT_BYTES.into()),
+    ];
 
-    let response_from_compact = client
-        .post("/age_named")
-        .body(rmp_serde::to_vec(&person).unwrap())
-        .dispatch()
-        .into_bytes()
-        .unwrap();
-    assert_eq!(response, response_from_compact);
-}
-
-#[test]
-fn check_compact_roundtrip() {
-    let client = Client::debug(rocket()).unwrap();
-    let person = Person {
-        name: "Maeve".to_string(),
-        age: 15,
-        gender: Gender::Female,
-    };
-    let response = client
-        .post("/age_compact")
-        .body(rmp_serde::to_vec(&person).unwrap())
-        .dispatch()
-        .into_bytes()
-        .unwrap();
-    let mut bytes = rmp::decode::Bytes::new(&response);
-    assert_eq!(rmp::decode::read_array_len(&mut bytes).unwrap(), 3);
-    assert_eq!(&read_string(&mut bytes), "Maeve");
-    assert_eq!(rmp::decode::read_int::<u8, _>(&mut bytes).unwrap(), 16);
-    // Equivalent to the named representation, gender here is encoded like this:
-    // `[ "Female" ]`.
-    assert_eq!(rmp::decode::read_array_len(&mut bytes).unwrap(), 1);
-    assert_eq!(&read_string(&mut bytes), "Female");
-
-    let response_from_named = client
-        .post("/age_compact")
-        .body(rmp_serde::to_vec_named(&person).unwrap())
-        .dispatch()
-        .into_bytes()
-        .unwrap();
-    assert_eq!(response, response_from_named);
+    for (name, input) in inputs {
+        let compact = client.post("/compact").body(input).dispatch();
+        assert_eq!(compact.into_bytes().unwrap(), COMPACT_BYTES, "{name} mismatch");
+
+        let named = client.post("/named").body(input).dispatch();
+        assert_eq!(named.into_bytes().unwrap(), NAMED_BYTES, "{name} mismatch");
+    }
 }