server: report why connections failed; Windows fd-exhaustion pause; review follow-ups

.changes/unreleased/Added-20260916-120000.yaml

@@ -7,14 +7,15 @@ body: |-
     HTTP/2 settings, keepalive, header-read timeout, max age / idle / request
     retirement, graceful GOAWAY on `shutdown`, panic isolation — and resolves
     to a `ConnectionClosed` whose `reason()` says how it ended
-    (`CloseReason::{Closed, Shutdown, MaxAge, Idle, MaxRequests, Error}`).
-    It runs on whichever runtime polls it; a tokio socket's I/O stays on the
-    runtime that created it until moved with `into_std` /
-    `TcpStream::from_std`. The new public `ConnectionInfo` (also at the crate
-    root) describes the connection: `peer_addr()`, `peer_certs()`, and
-    connection-scoped `extensions_mut()` that the loop fills once — a parsed
-    client-certificate identity, say — and that are cloned into every request
-    on the connection. `PeerAddr` / `PeerCerts` on requests always come from
+    (`CloseReason::{Closed, Shutdown, MaxAge, Idle, MaxRequests, Error}`) and
+    whose `error()` / `error_arc()` return the error that ended it, including
+    one hit while draining. It runs on whichever runtime polls it; a tokio
+    socket's I/O stays on the runtime that created it until moved with
+    `into_std` / `TcpStream::from_std`. The new public `ConnectionInfo` (also
+    at the crate root) describes the connection: `peer_addr()`,
+    `peer_certs()`, and connection-scoped `extensions_mut()` that the loop
+    fills once — a parsed client-certificate identity, say — and that are
+    cloned into every request on the connection. `PeerAddr` / `PeerCerts` on requests always come from
     `ConnectionInfo`'s typed fields, never from its extensions. A loop that
     admits connections by client identity, caps them per tenant, or places
     them on different runtimes keeps every guarantee of `Server::serve`

.changes/unreleased/Added-20260918-170000.yaml

@@ -0,0 +1,7 @@
+kind: Added
+body: |-
+    **`connectrpc::http`: re-export of the `http` crate.** Its types appear
+    throughout the public API — `http::Extensions` in the
+    `with_connection_extensions` function, header maps on requests and
+    responses — so code can name them without its own `http` dependency.
+time: 2026-09-18T17:00:00.000000000+00:00

.changes/unreleased/Fixed-20260916-140500.yaml

@@ -1,11 +1,8 @@
 kind: Fixed
 body: |-
-    **Idle reaping and file-descriptor exhaustion.** With
+    **Idle reaping no longer closes a streaming response.** With
     `with_max_connection_idle` set, a request now counts as in flight until
-    its response body has been sent, so a long streaming response is no
-    longer closed as idle. As with gRPC's `MaxConnectionIdle`, a client that
-    stops reading now keeps its connection until `with_max_connection_age`
-    retires it. After `EMFILE` / `ENFILE` the accept loop of
-    `Server` / `BoundServer` and `connectrpc::axum::serve_tls` pauses accepts
-    for up to a second, or until shutdown, instead of spinning.
+    its response body has been sent, not only until its response head. As
+    with gRPC's `MaxConnectionIdle`, a client that stops reading now keeps
+    its connection until `with_max_connection_age` retires it.
 time: 2026-09-16T14:05:00.000000000+00:00

.changes/unreleased/Fixed-20260916-140600.yaml

@@ -0,0 +1,8 @@
+kind: Fixed
+body: |-
+    **The accept loop pauses when out of file descriptors.** After `EMFILE` /
+    `ENFILE` (`WSAEMFILE` on Windows), the accept loop of `Server` /
+    `BoundServer` and `connectrpc::axum::serve_tls` pauses accepts for up to a
+    second, or until shutdown. Before, it retried at once on Unix, spinning a
+    core, and did not recognise the Windows code.
+time: 2026-09-16T14:06:00.000000000+00:00

Cargo.toml

@@ -67,9 +67,13 @@ tracing = "0.1"
 tracing-subscriber = { version = "0.3.20", features = ["env-filter"] }
 
 # HTTP server/client
-h2 = "0.4"
+# 0.4.15: the header-list-size tests expect its GOAWAY on oversized header lists.
+h2 = "0.4.15"
 hyper = "1"
-hyper-util = "0"
+# `ConnectionClosed::error` relies on the auto connection's `Interrupted`
+# "Cancelled" error for a shutdown before protocol detection (checked in
+# 0.1.19 and 0.1.20).
+hyper-util = "0.1.20"
 
 # TLS
 rustls = "0.23"

connectrpc/src/axum.rs

@@ -82,13 +82,16 @@ use crate::server::serve_with_listener;
 /// [`ConnectionConfig`] setting, graceful shutdown, panic isolation.
 ///
 /// See the [module docs](self) for what this adds over `axum::serve`. After
-/// running out of file descriptors (`EMFILE` / `ENFILE`) the loop pauses
-/// accepts for up to a second, or until the shutdown signal fires.
+/// running out of file descriptors (`EMFILE` / `ENFILE`, or `WSAEMFILE` on
+/// Windows) the loop pauses accepts for up to a second, or until the
+/// shutdown signal fires.
 ///
 /// # Errors
 ///
-/// The future resolves to `Err` only for a non-transient `accept(2)` error.
-/// Per-connection failures are logged and never end the loop.
+/// The future resolves to `Err` only for an accept error that is neither
+/// transient nor file-descriptor exhaustion, as for
+/// [`BoundServer::serve`](crate::BoundServer::serve). Per-connection
+/// failures are logged and never end the loop.
 pub fn serve(listener: TcpListener, router: axum::Router) -> Serve {
     Serve {
         listener,
@@ -128,9 +131,9 @@ pub fn serve(listener: TcpListener, router: axum::Router) -> Serve {
 ///
 /// # Errors
 ///
-/// As [`serve`]: only a non-transient `accept(2)` error. TLS handshake
-/// failures and timeouts are logged at `debug` / `warn` and never end the
-/// loop.
+/// As [`serve`]: only an accept error that is neither transient nor
+/// file-descriptor exhaustion. TLS handshake failures and timeouts are
+/// logged at `debug` / `warn` and never end the loop.
 #[cfg(feature = "server-tls")]
 #[cfg_attr(docsrs, doc(cfg(feature = "server-tls")))]
 pub fn serve_tls(

connectrpc/src/lib.rs

@@ -316,6 +316,12 @@ pub use error::SharedSource;
 /// `http-body` dependency to use generated code.
 pub use http_body;
 
+/// Re-export of the `http` crate, whose types, such as
+/// [`HeaderMap`](http::HeaderMap) and [`Extensions`](http::Extensions),
+/// appear throughout the public API — so consumers can name them without
+/// their own `http` dependency.
+pub use http;
+
 // Protocol detection
 pub use protocol::Protocol;
 pub use protocol::RequestProtocol;