api: Use thiserror to derive many Display + Error implementations

ruma-api/Cargo.toml

@@ -24,6 +24,7 @@ ruma-serde = { version = "0.2.3", path = "../ruma-serde" }
 serde = { version = "1.0.114", features = ["derive"] }
 serde_json = "1.0.57"
 strum = "0.19.2"
+thiserror = "1.0.20"
 
 [dev-dependencies]
 ruma-common = { version = "0.2.0", path = "../ruma-common" }

ruma-api/src/error.rs

@@ -4,9 +4,11 @@
 
 use std::{
     error::Error as StdError,
-    fmt::{self, Display, Formatter},
+    fmt::{self, Debug, Display, Formatter},
 };
 
+use thiserror::Error;
+
 use crate::EndpointError;
 
 // FIXME when `!` becomes stable use it
@@ -32,90 +34,45 @@ impl StdError for Void {}
 
 /// An error when converting one of ruma's endpoint-specific request or response
 /// types to the corresponding http type.
-#[derive(Debug)]
+#[derive(Debug, Error)]
 #[non_exhaustive]
 pub enum IntoHttpError {
     /// Tried to create an authentication request without an access token.
-    NeedsAuthentication,
-    /// JSON serialization failed.
-    Json(serde_json::Error),
-    /// Query parameter serialization failed.
-    Query(ruma_serde::urlencoded::ser::Error),
-    /// Header serialization failed.
-    Header(http::header::InvalidHeaderValue),
-    /// HTTP request construction failed.
-    Http(http::Error),
-}
-
-impl From<serde_json::Error> for IntoHttpError {
-    fn from(err: serde_json::Error) -> Self {
-        Self::Json(err)
-    }
-}
-
-impl From<ruma_serde::urlencoded::ser::Error> for IntoHttpError {
-    fn from(err: ruma_serde::urlencoded::ser::Error) -> Self {
-        Self::Query(err)
-    }
-}
-
-impl From<http::header::InvalidHeaderValue> for IntoHttpError {
-    fn from(err: http::header::InvalidHeaderValue) -> Self {
-        Self::Header(err)
-    }
-}
-
-impl From<http::Error> for IntoHttpError {
-    fn from(err: http::Error) -> Self {
-        Self::Http(err)
-    }
-}
-
-impl Display for IntoHttpError {
-    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
-        match &self {
-            Self::NeedsAuthentication => write!(
-                f,
+    #[error(
         "This endpoint has to be converted to http::Request using \
          try_into_authenticated_http_request"
-            ),
-            Self::Json(err) => write!(f, "JSON serialization failed: {}", err),
-            Self::Query(err) => write!(f, "Query parameter serialization failed: {}", err),
-            Self::Header(err) => write!(f, "Header serialization failed: {}", err),
-            Self::Http(err) => write!(f, "HTTP request construction failed: {}", err),
-        }
-    }
+    )]
+    NeedsAuthentication,
+
+    /// JSON serialization failed.
+    #[error("JSON serialization failed: {0}")]
+    Json(#[from] serde_json::Error),
+
+    /// Query parameter serialization failed.
+    #[error("Query parameter serialization failed: {0}")]
+    Query(#[from] ruma_serde::urlencoded::ser::Error),
+
+    /// Header serialization failed.
+    #[error("Header serialization failed: {0}")]
+    Header(#[from] http::header::InvalidHeaderValue),
+
+    /// HTTP request construction failed.
+    #[error("HTTP request construction failed: {0}")]
+    Http(#[from] http::Error),
 }
 
-impl StdError for IntoHttpError {}
-
-/// An error when converting a http request to one of ruma's endpoint-specific
-/// request types.
-#[derive(Debug)]
+/// An error when converting a http request to one of ruma's endpoint-specific request types.
+#[derive(Debug, Error)]
 #[non_exhaustive]
 pub enum FromHttpRequestError {
     /// Deserialization failed
-    Deserialization(RequestDeserializationError),
+    #[error("deserialization failed: {0}")]
+    Deserialization(#[from] RequestDeserializationError),
 }
 
-impl Display for FromHttpRequestError {
-    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
-        match self {
-            Self::Deserialization(err) => write!(f, "deserialization failed: {}", err),
-        }
-    }
-}
-
-impl From<RequestDeserializationError> for FromHttpRequestError {
-    fn from(err: RequestDeserializationError) -> Self {
-        Self::Deserialization(err)
-    }
-}
-
-impl StdError for FromHttpRequestError {}
-
 /// An error that occurred when trying to deserialize a request.
-#[derive(Debug)]
+#[derive(Debug, Error)]
+#[error("{inner}")]
 pub struct RequestDeserializationError {
     inner: DeserializationError,
     http_request: http::Request<Vec<u8>>,
@@ -132,16 +89,7 @@ impl RequestDeserializationError {
     }
 }
 
-impl Display for RequestDeserializationError {
-    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
-        Display::fmt(&self.inner, f)
-    }
-}
-
-impl StdError for RequestDeserializationError {}
-
-/// An error when converting a http response to one of ruma's endpoint-specific
-/// response types.
+/// An error when converting a http response to one of Ruma's endpoint-specific response types.
 #[derive(Debug)]
 #[non_exhaustive]
 pub enum FromHttpResponseError<E> {
@@ -232,70 +180,32 @@ impl<E: StdError> StdError for ServerError<E> {}
 
 /// An error when converting a http request / response to one of ruma's endpoint-specific request /
 /// response types.
-#[derive(Debug)]
+#[derive(Debug, Error)]
 #[non_exhaustive]
 pub enum DeserializationError {
     /// Encountered invalid UTF-8.
-    Utf8(std::str::Utf8Error),
+    #[error("{0}")]
+    Utf8(#[from] std::str::Utf8Error),
+
     /// JSON deserialization failed.
-    Json(serde_json::Error),
+    #[error("{0}")]
+    Json(#[from] serde_json::Error),
+
     /// Query parameter deserialization failed.
-    Query(ruma_serde::urlencoded::de::Error),
+    #[error("{0}")]
+    Query(#[from] ruma_serde::urlencoded::de::Error),
+
     /// Got an invalid identifier.
-    Ident(ruma_identifiers::Error),
+    #[error("{0}")]
+    Ident(#[from] ruma_identifiers::Error),
+
     /// Path segment deserialization failed.
-    Strum(strum::ParseError),
+    #[error("{0}")]
+    Strum(#[from] strum::ParseError),
+
     /// Header value deserialization failed.
-    Header(http::header::ToStrError),
-}
-
-impl Display for DeserializationError {
-    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
-        match self {
-            DeserializationError::Utf8(err) => Display::fmt(err, f),
-            DeserializationError::Json(err) => Display::fmt(err, f),
-            DeserializationError::Query(err) => Display::fmt(err, f),
-            DeserializationError::Ident(err) => Display::fmt(err, f),
-            DeserializationError::Strum(err) => Display::fmt(err, f),
-            DeserializationError::Header(err) => Display::fmt(err, f),
-        }
-    }
-}
-
-impl From<http::header::ToStrError> for DeserializationError {
-    fn from(err: http::header::ToStrError) -> Self {
-        Self::Header(err)
-    }
-}
-
-impl From<std::str::Utf8Error> for DeserializationError {
-    fn from(err: std::str::Utf8Error) -> Self {
-        Self::Utf8(err)
-    }
-}
-
-impl From<serde_json::Error> for DeserializationError {
-    fn from(err: serde_json::Error) -> Self {
-        Self::Json(err)
-    }
-}
-
-impl From<ruma_serde::urlencoded::de::Error> for DeserializationError {
-    fn from(err: ruma_serde::urlencoded::de::Error) -> Self {
-        Self::Query(err)
-    }
-}
-
-impl From<ruma_identifiers::Error> for DeserializationError {
-    fn from(err: ruma_identifiers::Error) -> Self {
-        Self::Ident(err)
-    }
-}
-
-impl From<strum::ParseError> for DeserializationError {
-    fn from(err: strum::ParseError) -> Self {
-        Self::Strum(err)
-    }
+    #[error("{0}")]
+    Header(#[from] http::header::ToStrError),
 }
 
 impl From<std::convert::Infallible> for DeserializationError {

ruma-api/src/lib.rs

@@ -236,7 +236,7 @@ pub trait Outgoing {
 }
 
 /// Gives users the ability to define their own serializable / deserializable errors.
-pub trait EndpointError: StdError + Sized {
+pub trait EndpointError: StdError + Sized + 'static {
     /// Tries to construct `Self` from an `http::Response`.
     ///
     /// This will always return `Err` variant when no `error` field is defined in