From 60010140784a286e53aa560cad6604caded4257e Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Fri, 13 Sep 2024 07:40:22 +0000
Subject: [PATCH] add UnwrapInfallible to Result

Signed-off-by: Jason Volk <jason@zemos.net>
---
 src/core/result.rs                   |  3 ++-
 src/core/result/unwrap_infallible.rs | 17 +++++++++++++++++
 src/router/serve/unix.rs             |  8 ++------
 3 files changed, 21 insertions(+), 7 deletions(-)
 create mode 100644 src/core/result/unwrap_infallible.rs

diff --git a/src/core/result.rs b/src/core/result.rs
index 41d1d66c..96a34b8a 100644
--- a/src/core/result.rs
+++ b/src/core/result.rs
@@ -3,10 +3,11 @@ mod log_debug_err;
 mod log_err;
 mod map_expect;
 mod not_found;
+mod unwrap_infallible;
 
 pub use self::{
 	debug_inspect::DebugInspect, log_debug_err::LogDebugErr, log_err::LogErr, map_expect::MapExpect,
-	not_found::NotFound,
+	not_found::NotFound, unwrap_infallible::UnwrapInfallible,
 };
 
 pub type Result<T = (), E = crate::Error> = std::result::Result<T, E>;
diff --git a/src/core/result/unwrap_infallible.rs b/src/core/result/unwrap_infallible.rs
new file mode 100644
index 00000000..99309e02
--- /dev/null
+++ b/src/core/result/unwrap_infallible.rs
@@ -0,0 +1,17 @@
+use std::convert::Infallible;
+
+use super::{DebugInspect, Result};
+use crate::error;
+
+pub trait UnwrapInfallible<T> {
+	fn unwrap_infallible(self) -> T;
+}
+
+impl<T> UnwrapInfallible<T> for Result<T, Infallible> {
+	#[inline]
+	fn unwrap_infallible(self) -> T {
+		// SAFETY: Branchless unwrap for errors that can never happen. In debug
+		// mode this is asserted.
+		unsafe { self.debug_inspect_err(error::infallible).unwrap_unchecked() }
+	}
+}
diff --git a/src/router/serve/unix.rs b/src/router/serve/unix.rs
index fb011f18..5df41b61 100644
--- a/src/router/serve/unix.rs
+++ b/src/router/serve/unix.rs
@@ -10,7 +10,7 @@ use axum::{
 	extract::{connect_info::IntoMakeServiceWithConnectInfo, Request},
 	Router,
 };
-use conduit::{debug, debug_error, error::infallible, info, trace, warn, Err, Result, Server};
+use conduit::{debug, debug_error, info, result::UnwrapInfallible, trace, warn, Err, Result, Server};
 use hyper::{body::Incoming, service::service_fn};
 use hyper_util::{
 	rt::{TokioExecutor, TokioIo},
@@ -62,11 +62,7 @@ async fn accept(
 	let socket = TokioIo::new(socket);
 	trace!(?listener, ?socket, ?remote, "accepted");
 
-	let called = app
-		.call(NULL_ADDR)
-		.await
-		.inspect_err(infallible)
-		.expect("infallible");
+	let called = app.call(NULL_ADDR).await.unwrap_infallible();
 
 	let service = move |req: Request<Incoming>| called.clone().oneshot(req);
 	let handler = service_fn(service);