default all feature flags to off

Changes the set of `default` feature flags to `[]`. By default, only
core traits are included without specifying feature flags. This makes it
easier for users to pick the components they need.

For convenience, a `full` feature flag is included that includes all
components.

Tests are configured to require the `full` feature. Testing individual
feature flags will need to be moved to a separate crate.

Closes #1791

azure-pipelines.yml

@@ -3,6 +3,7 @@ pr: ["master"]
 
 variables:
   RUSTFLAGS: -Dwarnings
+  nightly: 2019-11-16
 
 jobs:
 # Check formatting
@@ -80,9 +81,7 @@ jobs:
       - clippy
       - test_tokio
       - test_linux
-      # - test_features
       - loom
-#      - test_nightly
       - cross
-#      - minrust
+      - minrust
 #      - tsan

examples/Cargo.toml

@@ -5,8 +5,8 @@ publish = false
 edition = "2018"
 
 [dev-dependencies]
-tokio = { version = "=0.2.0-alpha.6", path = "../tokio" }
-tokio-util = { version = "=0.2.0-alpha.6", path = "../tokio-util" }
+tokio = { version = "=0.2.0-alpha.6", path = "../tokio", features = ["full"] }
+tokio-util = { version = "=0.2.0-alpha.6", path = "../tokio-util", features = ["full"] }
 
 bytes = { git = "https://github.com/tokio-rs/bytes" }
 futures = "0.3.0"

tokio-test/Cargo.toml

@@ -20,7 +20,7 @@ Testing utilities for Tokio- and futures-based code
 categories = ["asynchronous", "testing"]
 
 [dependencies]
-tokio = { version = "=0.2.0-alpha.6", path = "../tokio", features = ["test-util"] }
+tokio = { version = "=0.2.0-alpha.6", path = "../tokio", features = ["rt-core", "sync", "time", "test-util"] }
 
 bytes = { git = "https://github.com/tokio-rs/bytes" }
 futures-core = "0.3.0"

tokio-tls/Cargo.toml

@@ -29,6 +29,8 @@ native-tls = "0.2"
 tokio = { version = "=0.2.0-alpha.6", path = "../tokio" }
 
 [dev-dependencies]
+tokio = { version = "=0.2.0-alpha.6", path = "../tokio", features = ["macros", "stream", "rt-core", "io-util", "net"] }
+
 cfg-if = "0.1"
 env_logger = { version = "0.6", default-features = false }
 futures = { version = "0.3.0", features = ["async-await"] }

tokio-util/Cargo.toml

@@ -19,6 +19,16 @@ Additional utilities for working with Tokio.
 """
 categories = ["asynchronous"]
 
+[features]
+# No features on by default
+default = []
+
+# Shorthand for enabling everything
+full = ["codec", "udp"]
+
+codec = []
+udp = ["tokio/udp"]
+
 [dependencies]
 tokio = { version = "=0.2.0-alpha.6", path = "../tokio" }
 
@@ -36,3 +46,4 @@ futures = "0.3.0"
 
 [package.metadata.docs.rs]
 all-features = true
+rustdoc-args = ["--cfg", "docsrs"]

tokio-util/src/cfg.rs

@@ -0,0 +1,19 @@
+macro_rules! cfg_codec {
+    ($($item:item)*) => {
+        $(
+            #[cfg(feature = "codec")]
+            #[cfg_attr(docsrs, doc(cfg(feature = "codec")))]
+            $item
+        )*
+    }
+}
+
+macro_rules! cfg_udp {
+    ($($item:item)*) => {
+        $(
+            #[cfg(all(feature = "udp", feature = "codec"))]
+            #[cfg_attr(docsrs, doc(cfg(all(feature = "udp", feature = "codec"))))]
+            $item
+        )*
+    }
+}

tokio-util/src/lib.rs

@@ -10,8 +10,17 @@
     no_crate_inject,
     attr(deny(warnings, rust_2018_idioms), allow(dead_code, unused_variables))
 ))]
+#![cfg_attr(docsrs, feature(doc_cfg))]
 
 //! Utilities for working with Tokio.
 
-pub mod codec;
-pub mod udp;
+#[macro_use]
+mod cfg;
+
+cfg_codec! {
+    pub mod codec;
+}
+
+cfg_udp! {
+    pub mod udp;
+}

tokio-util/src/udp/frame.rs

@@ -27,6 +27,7 @@ use std::task::{Context, Poll};
 /// calling `split` on the `UdpFramed` returned by this method, which will break
 /// them into separate objects, allowing them to interact more easily.
 #[must_use = "sinks do nothing unless polled"]
+#[cfg_attr(docsrs, doc(feature = "codec-udp"))]
 #[derive(Debug)]
 pub struct UdpFramed<C> {
     socket: UdpSocket,

tokio/Cargo.toml

@@ -24,7 +24,8 @@ categories = ["asynchronous", "network-programming"]
 keywords = ["io", "async", "non-blocking", "futures"]
 
 [features]
-default = ["full"]
+# Include nothing by default
+default = []
 
 # enable everything
 full = [
@@ -48,7 +49,7 @@ full = [
 blocking = ["rt-core"]
 dns = ["rt-core"]
 fs = ["rt-core"]
-io-driver = ["rt-core", "mio", "lazy_static"]
+io-driver = ["mio", "lazy_static"]
 io-util = ["memchr"]
 # stdin, stdout, stderr
 io-std = ["rt-core"]
@@ -83,7 +84,7 @@ stream = ["futures-core"]
 sync = ["fnv"]
 test-util = []
 tcp = ["io-driver"]
-time = ["rt-core", "slab"]
+time = ["slab"]
 udp = ["io-driver"]
 uds = ["io-driver", "mio-uds", "libc"]
 

tokio/src/lib.rs

@@ -51,6 +51,13 @@
 //! control what features are present, so that unused code can be eliminated.
 //! This documentation also lists what feature flags are necessary to enable each API.
 //!
+//! The easiest way to get started is to enable all features. Do this by
+//! enabling the `full` feature flag:
+//!
+//! ```toml
+//! tokio = { version = "0.2", features = ["full"] }
+//! ```
+//!
 //! [features]: https://doc.rust-lang.org/cargo/reference/manifest.html#the-features-section
 //!
 //! ## Working With Tasks

tokio/tests/_require_full.rs

@@ -0,0 +1,2 @@
+#![cfg(not(feature = "full"))]
+compile_error!("run main Tokio tests with `--features full`");

tokio/tests/buffered.rs

@@ -1,4 +1,5 @@
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
 
 use tokio::net::TcpListener;
 use tokio::prelude::*;

tokio/tests/fs_dir.rs

@@ -1,4 +1,5 @@
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
 
 use tokio::fs;
 use tokio_test::assert_ok;

tokio/tests/fs_file.rs

@@ -1,4 +1,5 @@
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
 
 use tokio::fs::File;
 use tokio::prelude::*;

tokio/tests/fs_file_mocked.rs

@@ -1,4 +1,5 @@
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
 
 macro_rules! ready {
     ($e:expr $(,)?) => {

tokio/tests/fs_link.rs

@@ -1,4 +1,5 @@
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
 
 use tokio::fs;
 

tokio/tests/io_async_read.rs

@@ -1,3 +1,6 @@
+#![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
+
 use tokio::io::AsyncRead;
 use tokio_test::task;
 use tokio_test::{assert_ready_err, assert_ready_ok};

tokio/tests/io_chain.rs

@@ -1,4 +1,5 @@
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
 
 use tokio::io::AsyncReadExt;
 use tokio_test::assert_ok;

tokio/tests/io_copy.rs

@@ -1,4 +1,5 @@
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
 
 use tokio::io::{AsyncRead, AsyncReadExt};
 use tokio_test::assert_ok;

tokio/tests/io_driver.rs

@@ -1,4 +1,5 @@
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
 
 use tokio::net::TcpListener;
 use tokio::runtime;

tokio/tests/io_driver_drop.rs

@@ -1,4 +1,5 @@
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
 
 use tokio::net::TcpListener;
 use tokio::runtime;

tokio/tests/io_lines.rs

@@ -1,4 +1,5 @@
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
 
 use tokio::io::AsyncBufReadExt;
 use tokio_test::assert_ok;

tokio/tests/io_read.rs

@@ -1,4 +1,5 @@
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
 
 use tokio::io::{AsyncRead, AsyncReadExt};
 use tokio_test::assert_ok;

tokio/tests/io_read_exact.rs

@@ -1,4 +1,5 @@
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
 
 use tokio::io::AsyncReadExt;
 use tokio_test::assert_ok;

tokio/tests/io_read_line.rs

@@ -1,4 +1,5 @@
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
 
 use tokio::io::AsyncBufReadExt;
 use tokio_test::assert_ok;

tokio/tests/io_read_to_end.rs

@@ -1,4 +1,5 @@
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
 
 use tokio::io::AsyncReadExt;
 use tokio_test::assert_ok;

tokio/tests/io_read_to_string.rs

@@ -1,4 +1,5 @@
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
 
 use tokio::io::AsyncReadExt;
 use tokio_test::assert_ok;

tokio/tests/io_read_until.rs

@@ -1,4 +1,5 @@
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
 
 use tokio::io::AsyncBufReadExt;
 use tokio_test::assert_ok;

tokio/tests/io_split.rs

@@ -1,3 +1,6 @@
+#![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
+
 use tokio::io::{split, AsyncRead, AsyncWrite, ReadHalf, WriteHalf};
 
 use std::io;

tokio/tests/io_take.rs

@@ -1,4 +1,5 @@
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
 
 use tokio::io::AsyncReadExt;
 use tokio_test::assert_ok;

tokio/tests/io_write.rs

@@ -1,4 +1,5 @@
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
 
 use tokio::io::{AsyncWrite, AsyncWriteExt};
 use tokio_test::assert_ok;

tokio/tests/io_write_all.rs

@@ -1,4 +1,5 @@
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
 
 use tokio::io::{AsyncWrite, AsyncWriteExt};
 use tokio_test::assert_ok;

tokio/tests/net_bind_resource.rs

@@ -1,3 +1,6 @@
+#![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
+
 use tokio::net::TcpListener;
 
 use std::convert::TryFrom;

tokio/tests/process_issue_42.rs

@@ -1,6 +1,6 @@
-#![cfg(feature = "process")]
-#![cfg(unix)]
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
+#![cfg(unix)]
 
 use tokio::process::Command;
 use tokio::runtime;

tokio/tests/process_smoke.rs

@@ -1,5 +1,5 @@
-#![cfg(feature = "process")]
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
 
 use tokio::process::Command;
 use tokio_test::assert_ok;

tokio/tests/rt_basic.rs

@@ -1,4 +1,5 @@
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
 
 use tokio::runtime::Runtime;
 use tokio::sync::oneshot;

tokio/tests/rt_common.rs

@@ -1,6 +1,7 @@
-// Tests to run on both current-thread & therad-pool runtime variants.
-
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
+
+// Tests to run on both current-thread & therad-pool runtime variants.
 
 macro_rules! rt_test {
     ($($t:tt)*) => {

tokio/tests/rt_threaded.rs

@@ -1,4 +1,5 @@
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
 
 use tokio::io::{AsyncReadExt, AsyncWriteExt};
 use tokio::net::{TcpListener, TcpStream};

tokio/tests/signal_ctrl_c.rs

@@ -1,5 +1,6 @@
-#![cfg(unix)]
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
+#![cfg(unix)]
 
 mod support {
     pub mod signal;

tokio/tests/signal_drop_recv.rs

@@ -1,5 +1,6 @@
-#![cfg(unix)]
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
+#![cfg(unix)]
 
 mod support {
     pub mod signal;

tokio/tests/signal_drop_rt.rs

@@ -1,5 +1,6 @@
-#![cfg(unix)]
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
+#![cfg(unix)]
 
 mod support {
     pub mod signal;

tokio/tests/signal_drop_signal.rs

@@ -1,5 +1,6 @@
-#![cfg(unix)]
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
+#![cfg(unix)]
 
 mod support {
     pub mod signal;

tokio/tests/signal_multi_rt.rs

@@ -1,5 +1,6 @@
-#![cfg(unix)]
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
+#![cfg(unix)]
 
 mod support {
     pub mod signal;

tokio/tests/signal_no_rt.rs

@@ -1,5 +1,6 @@
-#![cfg(unix)]
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
+#![cfg(unix)]
 
 use tokio::signal::unix::{signal, SignalKind};
 

tokio/tests/signal_notify_both.rs

@@ -1,5 +1,6 @@
-#![cfg(unix)]
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
+#![cfg(unix)]
 
 mod support {
     pub mod signal;

tokio/tests/signal_twice.rs

@@ -1,5 +1,6 @@
-#![cfg(unix)]
 #![warn(rust_2018_idioms)]
+#![cfg(feature = "full")]
+#![cfg(unix)]
 
 mod support {
     pub mod signal;