From 467e7afd5e0148b264c76c606b67b8679ef7c55f Mon Sep 17 00:00:00 2001
From: florianjacob <projects+git@florianjacob.de>
Date: Wed, 12 Aug 2020 14:00:44 +0200
Subject: [PATCH] Require std::error::Error for EndpointError

and implement it for ruma_api::error::FromHttpResponseError and Void.
This allows integrating EndpointErrors in the common rust error
ecosystem like thiserror and anyhow.
---
 ruma-api/CHANGELOG.md          |  6 ++++++
 ruma-api/src/error.rs          | 10 ++++++++++
 ruma-api/src/lib.rs            |  2 +-
 ruma-client-api/src/r0/uiaa.rs |  2 ++
 4 files changed, 19 insertions(+), 1 deletion(-)

diff --git a/ruma-api/CHANGELOG.md b/ruma-api/CHANGELOG.md
index cc70e558..0b62cdd0 100644
--- a/ruma-api/CHANGELOG.md
+++ b/ruma-api/CHANGELOG.md
@@ -3,6 +3,12 @@
 Breaking changes:
 
 * Update strum dependency to 0.19
+* The `EndpointError` trait now requires `std::error::Error`. This allows integrating `EndpointError`s in the common
+  rust error ecosystem like `thiserror` and `anyhow`.
+
+Improvements:
+
+* The `EndpointError`s that come with ruma crates now implement `std::errror::Error`.
 
 # 0.17.0
 
diff --git a/ruma-api/src/error.rs b/ruma-api/src/error.rs
index 95223fe1..c118ece2 100644
--- a/ruma-api/src/error.rs
+++ b/ruma-api/src/error.rs
@@ -17,6 +17,14 @@ impl crate::EndpointError for Void {
     }
 }
 
+impl Display for Void {
+    fn fmt(&self, _: &mut fmt::Formatter<'_>) -> fmt::Result {
+        match self {}
+    }
+}
+
+impl std::error::Error for Void {}
+
 /// An error when converting one of ruma's endpoint-specific request or response
 /// types to the corresponding http type.
 #[derive(Debug)]
@@ -162,6 +170,8 @@ impl<E> From<ResponseDeserializationError> for FromHttpResponseError<E> {
     }
 }
 
+impl<E: std::error::Error> std::error::Error for FromHttpResponseError<E> {}
+
 /// An error that occurred when trying to deserialize a response.
 #[derive(Debug)]
 pub struct ResponseDeserializationError {
diff --git a/ruma-api/src/lib.rs b/ruma-api/src/lib.rs
index 3f5f308c..426ec064 100644
--- a/ruma-api/src/lib.rs
+++ b/ruma-api/src/lib.rs
@@ -232,7 +232,7 @@ pub trait Outgoing {
 }
 
 /// Gives users the ability to define their own serializable/deserializable errors.
-pub trait EndpointError: Sized {
+pub trait EndpointError: std::error::Error + Sized {
     /// Tries to construct `Self` from an `http::Response`.
     ///
     /// This will always return `Err` variant when no `error` field is defined in
diff --git a/ruma-client-api/src/r0/uiaa.rs b/ruma-client-api/src/r0/uiaa.rs
index ffafb8a6..9b1bcb31 100644
--- a/ruma-client-api/src/r0/uiaa.rs
+++ b/ruma-client-api/src/r0/uiaa.rs
@@ -119,6 +119,8 @@ impl EndpointError for UiaaResponse {
     }
 }
 
+impl std::error::Error for UiaaResponse {}
+
 impl From<UiaaResponse> for http::Response<Vec<u8>> {
     fn from(uiaa_response: UiaaResponse) -> http::Response<Vec<u8>> {
         match uiaa_response {