From 76cf6dd1013e976c38e4513a5f278c04e66bda2a Mon Sep 17 00:00:00 2001
From: Sean McArthur <sean@seanmonstar.com>
Date: Mon, 11 Sep 2023 15:59:05 -0400
Subject: [PATCH] feat(error): change `Display for Error` to only print top
 error

hyper's `Error` used to print the error source automatically, preferring
to provide a better default for users who do not know about `Report`.
But, to fit better with the wider ecosystem, this changes the format to
only print the hyper `Error` itself, and not its source.

Closes #2844

BREAKING CHANGE: The format no longer prints the error chain. Be sure to
  check if you are logging errors directly.

  The `Error::message()` method is removed, it is no longer needed.

  The `Error::into_cause()` method is removed.
---
 src/error.rs    | 28 +++++++++++++---------------
 tests/client.rs |  4 ----
 2 files changed, 13 insertions(+), 19 deletions(-)

diff --git a/src/error.rs b/src/error.rs
index b07a22c409..02e8002922 100644
--- a/src/error.rs
+++ b/src/error.rs
@@ -8,6 +8,18 @@ pub type Result<T> = std::result::Result<T, Error>;
 type Cause = Box<dyn StdError + Send + Sync>;
 
 /// Represents errors that can occur handling HTTP streams.
+///
+/// # Formatting
+///
+/// The `Display` implementation of this type will only print the details of
+/// this level of error, even though it may have been caused by another error
+/// and contain that error in its source. To print all the relevant
+/// information, including the source chain, using something like
+/// `std::error::Report`, or equivalent 3rd party types.
+///
+/// The contents of the formatted error message of this specific `Error` type
+/// is unspecified. **You must not depend on it.** The wording and details may
+/// change in any version, with the goal of improving error messages.
 pub struct Error {
     inner: Box<ErrorImpl>,
 }
@@ -173,11 +185,6 @@ impl Error {
         self.find_source::<TimedOut>().is_some()
     }
 
-    /// Consumes the error, returning its cause.
-    pub fn into_cause(self) -> Option<Box<dyn StdError + Send + Sync>> {
-        self.inner.cause
-    }
-
     pub(super) fn new(kind: Kind) -> Error {
         Error {
             inner: Box::new(ErrorImpl { kind, cause: None }),
@@ -332,11 +339,6 @@ impl Error {
         }
     }
 
-    /// The error's standalone message, without the message from the source.
-    pub fn message(&self) -> impl fmt::Display + '_ {
-        self.description()
-    }
-
     fn description(&self) -> &str {
         match self.inner.kind {
             Kind::Parse(Parse::Method) => "invalid HTTP method parsed",
@@ -420,11 +422,7 @@ impl fmt::Debug for Error {
 
 impl fmt::Display for Error {
     fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
-        if let Some(ref cause) = self.inner.cause {
-            write!(f, "{}: {}", self.description(), cause)
-        } else {
-            f.write_str(self.description())
-        }
+        f.write_str(self.description())
     }
 }
 
diff --git a/tests/client.rs b/tests/client.rs
index 3d46c3fbfa..1d19f8ea1d 100644
--- a/tests/client.rs
+++ b/tests/client.rs
@@ -2318,10 +2318,6 @@ mod conn {
         let error = client.send_request(req).await.unwrap_err();
 
         assert!(error.is_user());
-        assert_eq!(
-            error.to_string(),
-            "dispatch task is gone: user code panicked"
-        );
     }
 
     async fn drain_til_eof<T: tokio::io::AsyncRead + Unpin>(mut sock: T) -> io::Result<()> {