rt: Remove `threaded_scheduler()` and `basic_scheduler()` (#2876)

Co-authored-by: Alice Ryhl <alice@ryhl.io>
Co-authored-by: Carl Lerche <me@carllerche.com>

3 files changed, 34 insertions, 16 deletions

diff --git a/tokio/src/io/driver/mod.rs b/tokio/src/io/driver/mod.rs
index c4f5887a..0d4133a5 100644
--- a/tokio/src/io/driver/mod.rs
+++ b/tokio/src/io/driver/mod.rs
@@ -1,3 +1,5 @@
+#![cfg_attr(not(feature = "rt-core"), allow(dead_code))]
+
 mod ready;
 use ready::Ready;
 
@@ -5,7 +7,6 @@ mod scheduled_io;
 pub(crate) use scheduled_io::ScheduledIo; // pub(crate) for tests
 
 use crate::park::{Park, Unpark};
-use crate::runtime::context;
 use crate::util::bit;
 use crate::util::slab::{self, Slab};
 
@@ -218,17 +219,36 @@ impl fmt::Debug for Driver {
 
 // ===== impl Handle =====
 
-impl Handle {
-    /// Returns a handle to the current reactor
-    ///
-    /// # Panics
-    ///
-    /// This function panics if there is no current reactor set.
-    pub(super) fn current() -> Self {
-        context::io_handle()
-            .expect("there is no reactor running, must be called from the context of Tokio runtime")
+cfg_rt_core! {
+    impl Handle {
+        /// Returns a handle to the current reactor
+        ///
+        /// # Panics
+        ///
+        /// This function panics if there is no current reactor set and `rt-core` feature
+        /// flag is not enabled.
+        pub(super) fn current() -> Self {
+            crate::runtime::context::io_handle()
+                .expect("there is no reactor running, must be called from the context of Tokio runtime")
+        }
     }
+}
 
+cfg_not_rt_core! {
+    impl Handle {
+        /// Returns a handle to the current reactor
+        ///
+        /// # Panics
+        ///
+        /// This function panics if there is no current reactor set, or if the `rt-core`
+        /// feature flag is not enabled.
+        pub(super) fn current() -> Self {
+            panic!("there is no reactor running, must be called from the context of Tokio runtime with `rt-core` enabled.")
+        }
+    }
+}
+
+impl Handle {
     /// Forces a reactor blocked in a call to `turn` to wakeup, or otherwise
     /// makes the next call to `turn` return immediately.
     ///
diff --git a/tokio/src/io/mod.rs b/tokio/src/io/mod.rs
index e1a036fb..62728ac1 100644
--- a/tokio/src/io/mod.rs
+++ b/tokio/src/io/mod.rs
@@ -250,7 +250,7 @@ cfg_io_blocking! {
     /// Types in this module can be mocked out in tests.
     mod sys {
         // TODO: don't rename
-        pub(crate) use crate::runtime::spawn_blocking as run;
-        pub(crate) use crate::task::JoinHandle as Blocking;
+        pub(crate) use crate::blocking::spawn_blocking as run;
+        pub(crate) use crate::blocking::JoinHandle as Blocking;
     }
 }
diff --git a/tokio/src/io/stdio_common.rs b/tokio/src/io/stdio_common.rs
index 03800fcb..d21c842f 100644
--- a/tokio/src/io/stdio_common.rs
+++ b/tokio/src/io/stdio_common.rs
@@ -183,8 +183,7 @@ mod tests {
         let fut = async move {
             wr.write_all(data.as_bytes()).await.unwrap();
         };
-        crate::runtime::Builder::new()
-            .basic_scheduler()
+        crate::runtime::Builder::new_current_thread()
             .build()
             .unwrap()
             .block_on(fut);
@@ -200,8 +199,7 @@ mod tests {
         data.extend(std::iter::repeat(0b1010_1010).take(MAX_BUF - checked_count + 1));
         let mut writer = LoggingMockWriter::new();
         let mut splitter = super::SplitByUtf8BoundaryIfWindows::new(&mut writer);
-        crate::runtime::Builder::new()
-            .basic_scheduler()
+        crate::runtime::Builder::new_current_thread()
             .build()
             .unwrap()
             .block_on(async {