hyper: drop support

lib : remove all hyper code
configure: stop detecting hyper
docs: no more mention of hyper
tests: mo more special-handling of hyper builds
CI: no jobs using hyper

Closes #15120

docs/DEPRECATE.md

@@ -23,36 +23,6 @@ and use TLS 1.3, or else it is not good enough.
 As of May 2024, the libraries that need to get fixed to remain supported after
 May 2025 are: BearSSL and Secure Transport.
 
-## Hyper
-
-Hyper is an alternative HTTP backend for curl. It uses the hyper library and
-could in theory be used for HTTP/1, HTTP/2 and even HTTP/3 in the future with
-curl.
-
-The original plan and goal was that we would add this HTTP alternative (using
-a memory-safe library) and that users could eventually build and use libcurl
-exactly as previously but with parts of the core being more memory-safe.
-
-The hyper implementation ran into some snags and 10-15 tests and HTTP/2
-support have remained disabled with hyper. For these reasons, hyper support
-has remained tagged EXPERIMENTAL.
-
-It is undoubtedly hard work to fix these remaining problems, as they typically
-require both rust and C knowledge in addition to deep HTTP familiarity. There
-does not seem to be that many persons interested or available for this
-challenge. Meanwhile, there is little if any demand for hyper from existing
-(lib)curl users.
-
-Finally: having support for hyper in curl has a significant cost: we need to
-maintain and develop a lot of functionality and tests twice to make sure
-libcurl works identically using either HTTP backend.
-
-The only way to keep hyper support in curl is to give it a good polish by
-someone with time, skill and energy to spend on this task.
-
-Unless a significant overhaul has proven to be in progress, hyper support is
-removed from curl in January 2025.
-
 ## Past removals
 
  - Pipelining
@@ -65,3 +35,4 @@ removed from curl in January 2025.
  - MinGW v1
  - NTLM_WB
  - space-separated `NOPROXY` patterns
+ - hyper

docs/EXPERIMENTAL.md

@@ -34,14 +34,6 @@ Experimental support in curl means:
 
 ## Experimental features right now
 
-### The Hyper HTTP backend
-
-Graduation requirements:
-
-- HTTP/1 and HTTP/2 support, including multiplexing
-
-(Hyper is marked for deprecation. It cannot graduate.)
-
 ###  HTTP/3 support (non-ngtcp2 backends)
 
 Graduation requirements:

docs/Makefile.am

@@ -50,7 +50,6 @@ INTERNALDOCS =                                  \
  internals/CONNECTION-FILTERS.md                \
  internals/DYNBUF.md                            \
  internals/HASH.md                              \
- internals/HYPER.md                             \
  internals/LLIST.md                             \
  internals/MQTT.md                              \
  internals/NEW-PROTOCOL.md                      \

docs/cmdline-opts/ignore-content-length.md

@@ -15,11 +15,9 @@ Example:
 
 # `--ignore-content-length`
 
-For HTTP, Ignore the Content-Length header. This is particularly useful for
-servers running Apache 1.x, which reports incorrect Content-Length for
-files larger than 2 gigabytes.
+For HTTP, ignore the Content-Length header. This is particularly useful for
+servers running Apache 1.x, which reports incorrect Content-Length for files
+larger than 2 gigabytes.
 
 For FTP, this makes curl skip the SIZE command to figure out the size before
 downloading a file (added in 7.46.0).
-
-This option does not work for HTTP if libcurl was built to use hyper.

docs/internals/HYPER.md

@@ -1,78 +0,0 @@
-<!--
-Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
-
-SPDX-License-Identifier: curl
--->
-
-# Hyper
-
-Hyper is a separate HTTP library written in Rust. curl can be told to use this
-library as a backend to deal with HTTP.
-
-## EXPERIMENTAL
-
-Hyper support in curl is considered **EXPERIMENTAL** until further notice. It
-needs to be explicitly enabled at build-time.
-
-Further development and tweaking of the Hyper backend support in curl happens
-in the master branch using pull-requests, just like ordinary changes.
-
-## Hyper version
-
-The C API for Hyper is brand new and is still under development.
-
-## Build curl with hyper
-
-Using Rust 1.64.0 or later, build hyper and enable its C API like this:
-
-     % git clone https://github.com/hyperium/hyper
-     % cd hyper
-     % RUSTFLAGS="--cfg hyper_unstable_ffi" cargo rustc --features client,http1,http2,ffi --crate-type cdylib
-
-Also, `--release` can be added for a release (optimized) build.
-
-Build curl to use hyper's C API:
-
-     % git clone https://github.com/curl/curl
-     % cd curl
-     % autoreconf -fi
-     % ./configure LDFLAGS="-Wl,-rpath,<hyper-dir>/target/debug -Wl,-rpath,<hyper-dir>/target/release" --with-openssl --with-hyper=<hyper-dir>
-     % make
-
-# Using Hyper internally
-
-Hyper is a low level HTTP transport library. curl itself provides all HTTP
-headers and Hyper provides all received headers back to curl.
-
-Therefore, most of the "header logic" in curl as in responding to and acting
-on specific input and output headers are done the same way in curl code.
-
-The API in Hyper delivers received HTTP headers as (cleaned up) name=value
-pairs, making it impossible for curl to know the exact byte representation
-over the wire with Hyper.
-
-## Limitations
-
-The hyper backend does not support
-
-- `CURLOPT_IGNORE_CONTENT_LENGTH`
-- `--raw` and disabling `CURLOPT_HTTP_TRANSFER_DECODING`
-- RTSP
-- hyper is much stricter about what HTTP header contents it allows
-- leading whitespace in first HTTP/1 response header
-- HTTP/0.9
-- HTTP/2 upgrade using HTTP:// URLs. Aka 'h2c'
-- HTTP/2 in general. Hyper has support for HTTP/2 but the curl side
-  needs changes so that a `hyper_clientconn` can last for the duration
-  of a connection. Probably this means turning the Hyper HTTP/2 backend
-  into a connection filter.
-
-## Remaining issues
-
-This backend is still not feature complete with the native backend. Areas that
-still need attention and verification include:
-
-- multiplexed HTTP/2
-- h2 Upgrade:
-- receiving HTTP/1 trailers
-- sending HTTP/1 trailers

docs/internals/WEBSOCKET.md

@@ -99,7 +99,6 @@ Ideas:
 
 - Verify the Sec-WebSocket-Accept response. It requires a sha-1 function.
 - Verify Sec-WebSocket-Extensions and Sec-WebSocket-Protocol in the response
-- Make WebSocket work with hyper
 - Consider a `curl_ws_poll()`
 - Make sure WebSocket code paths are fuzzed
 - Add client-side PING interval

docs/libcurl/opts/CURLOPT_HTTP_TRANSFER_DECODING.md

@@ -31,11 +31,6 @@ Pass a long to tell libcurl how to act on transfer decoding. If set to zero,
 transfer decoding is disabled, if set to 1 it is enabled (default). libcurl
 does chunked transfer decoding by default unless this option is set to zero.
 
-# NOTES
-
-This option does not work with the hyper backend as that always has transfer
-decoding enabled.
-
 # DEFAULT
 
 1

docs/libcurl/opts/CURLOPT_IGNORE_CONTENT_LENGTH.md

@@ -69,11 +69,6 @@ int main(void)
 
 Support for FTP added in 7.46.0.
 
-# NOTES
-
-This option is not working for HTTP when libcurl is built to use the hyper
-backend.
-
 # %AVAILABILITY%
 
 # RETURN VALUE