feat(lib): disable all optional features by default (#2336)

BREAKING CHANGE: All optional features have been disabled by default.

.github/workflows/CI.yml

@@ -59,11 +59,11 @@ jobs:
 
         include:
           - rust: stable
-            features: ""
+            features: "--features full"
           - rust: beta
-            features: ""
+            features: "--features full"
           - rust: nightly
-            features: "--features nightly"
+            features: "--features full,nightly"
             benches: true
 
     runs-on: ${{ matrix.os }}
@@ -132,4 +132,4 @@ jobs:
         uses: actions-rs/cargo@v1
         with:
           command: rustdoc
-          args: -- -D broken-intra-doc-links
+          args: --features full -- -D broken-intra-doc-links

.github/workflows/bench.yml

@@ -26,7 +26,7 @@ jobs:
 
       # Run benchmark and stores the output to a file
       - name: Run benchmark
-        run: cargo bench --bench ${{ matrix.bench }} | tee output.txt
+        run: cargo bench --features full --bench ${{ matrix.bench }} | tee output.txt
 
       # Download previous benchmark result from cache (if exists)
       - name: Download previous benchmark data

Cargo.toml

@@ -71,14 +71,10 @@ url = "1.0"
 pnet = "0.25.0"
 
 [features]
-default = [
-    "runtime",
-    "stream",
-    "client",
-    "server",
-    "http1",
-    "http2",
-]
+# Nothing by default
+default = []
+
+# Easily turn it all on
 full = [
     "client",
     "http1",
@@ -87,16 +83,6 @@ full = [
     "stream",
     "runtime",
 ]
-runtime = [
-    "tcp",
-    "tokio/rt",
-]
-tcp = [
-    "socket2",
-    "tokio/net",
-    "tokio/rt",
-    "tokio/time",
-]
 
 # HTTP versions
 http1 = []
@@ -109,6 +95,19 @@ server = []
 # `impl Stream` for things
 stream = []
 
+# Tokio support
+
+runtime = [
+    "tcp",
+    "tokio/rt",
+]
+tcp = [
+    "socket2",
+    "tokio/net",
+    "tokio/rt",
+    "tokio/time",
+]
+
 # internal features used in CI
 nightly = []
 __internal_happy_eyeballs_tests = []
@@ -131,122 +130,122 @@ incremental = false
 [[example]]
 name = "client"
 path = "examples/client.rs"
-required-features = ["runtime"]
+required-features = ["full"]
 
 [[example]]
 name = "client_json"
 path = "examples/client_json.rs"
-required-features = ["runtime"]
+required-features = ["full"]
 
 [[example]]
 name = "echo"
 path = "examples/echo.rs"
-required-features = ["runtime", "stream"]
+required-features = ["full"]
 
 [[example]]
 name = "gateway"
 path = "examples/gateway.rs"
-required-features = ["runtime"]
+required-features = ["full"]
 
 [[example]]
 name = "hello"
 path = "examples/hello.rs"
-required-features = ["runtime"]
+required-features = ["full"]
 
 [[example]]
 name = "http_proxy"
 path = "examples/http_proxy.rs"
-required-features = ["runtime"]
+required-features = ["full"]
 
 [[example]]
 name = "multi_server"
 path = "examples/multi_server.rs"
-required-features = ["runtime"]
+required-features = ["full"]
 
 [[example]]
 name = "params"
 path = "examples/params.rs"
-required-features = ["runtime", "stream"]
+required-features = ["full"]
 
 [[example]]
 name = "send_file"
 path = "examples/send_file.rs"
-required-features = ["runtime"]
+required-features = ["full"]
 
 [[example]]
 name = "service_struct_impl"
 path = "examples/service_struct_impl.rs"
-required-features = ["runtime"]
+required-features = ["full"]
 
 [[example]]
 name = "single_threaded"
 path = "examples/single_threaded.rs"
-required-features = ["runtime"]
+required-features = ["full"]
 
 [[example]]
 name = "state"
 path = "examples/state.rs"
-required-features = ["runtime"]
+required-features = ["full"]
 
 [[example]]
 name = "tower_client"
 path = "examples/tower_client.rs"
-required-features = ["runtime"]
+required-features = ["full"]
 
 [[example]]
 name = "tower_server"
 path = "examples/tower_server.rs"
-required-features = ["runtime"]
+required-features = ["full"]
 
 [[example]]
 name = "upgrades"
 path = "examples/upgrades.rs"
-required-features = ["runtime"]
+required-features = ["full"]
 
 
 [[example]]
 name = "web_api"
 path = "examples/web_api.rs"
-required-features = ["runtime", "stream"]
+required-features = ["full"]
 
 
 [[bench]]
 name = "body"
 path = "benches/body.rs"
-required-features = ["runtime", "stream"]
+required-features = ["full"]
 
 [[bench]]
 name = "connect"
 path = "benches/connect.rs"
-required-features = ["runtime"]
+required-features = ["full"]
 
 [[bench]]
 name = "end_to_end"
 path = "benches/end_to_end.rs"
-required-features = ["runtime"]
+required-features = ["full"]
 
 [[bench]]
 name = "pipeline"
 path = "benches/pipeline.rs"
-required-features = ["runtime"]
+required-features = ["full"]
 
 [[bench]]
 name = "server"
 path = "benches/server.rs"
-required-features = ["runtime", "stream"]
+required-features = ["full"]
 
 
 [[test]]
 name = "client"
 path = "tests/client.rs"
-required-features = ["runtime", "stream"]
+required-features = ["full"]
 
 [[test]]
 name = "integration"
 path = "tests/integration.rs"
-required-features = ["runtime", "stream"]
+required-features = ["full"]
 
 [[test]]
 name = "server"
 path = "tests/server.rs"
-required-features = ["runtime"]
+required-features = ["full"]

src/common/io/rewind.rs

@@ -14,8 +14,7 @@ pub(crate) struct Rewind<T> {
 }
 
 impl<T> Rewind<T> {
-    #[cfg(any(feature = "http2", test))]
-    #[cfg(feature = "server")]
+    #[cfg(any(all(feature = "http2", feature = "server"), test))]
     pub(crate) fn new(io: T) -> Self {
         Rewind {
             pre: None,

src/lib.rs

@@ -31,14 +31,29 @@
 //!
 //! # Optional Features
 //!
+//! hyper uses a set of [feature flags] to reduce the amount of compiled code.
+//! It is possible to just enable certain features over others. By default,
+//! hyper does not enable any features but allows one to enable a subset for
+//! their use case. Below is a list of the available feature flags. You may
+//! also notice above each function, struct and trait there is listed one or
+//! more feature flags that are required for that item to be used.
+//!
+//! If you are new to hyper it is possible to enable the `full` feature flag
+//! which will enable all public APIs. Beware though that this will pull in
+//! many extra dependencies that you may not need.
+//!
 //! The following optional features are available:
 //!
-//! - `runtime` (*enabled by default*): Enables convenient integration with
-//!   `tokio`, providing connectors and acceptors for TCP, and a default
-//!   executor.
-//! - `tcp` (*enabled by default*): Enables convenient implementations over
-//!   TCP (using tokio).
-//! - `stream` (*enabled by default*): Provides `futures::Stream` capabilities.
+//! - `http1`: Enables HTTP/1 support.
+//! - `http2`: Enables HTTP/2 support.
+//! - `client`: Enables the HTTP `client`.
+//! - `server`: Enables the HTTP `server`.
+//! - `runtime`: Enables convenient integration with `tokio`, providing
+//!   connectors and acceptors for TCP, and a default executor.
+//! - `tcp`: Enables convenient implementations over TCP (using tokio).
+//! - `stream`: Provides `futures::Stream` capabilities.
+//!
+//! [feature flags]: https://doc.rust-lang.org/cargo/reference/manifest.html#the-features-section
 
 #[doc(hidden)]
 pub use http;