Merge pull request #154 from yoshuawuyts/empty-lists

handle empty lists for `{try,}join`
yoshuawuyts · Aug 25, 2023 · a43c735 · a43c735
2 parents 524a7ce + 1532698
commit a43c735
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Showing 4 changed files with 40 additions and 4 deletions.
diff --git a/src/future/join/array.rs b/src/future/join/array.rs
@@ -95,7 +95,7 @@ where
 
         let mut readiness = this.wakers.readiness().lock().unwrap();
         readiness.set_waker(cx.waker());
-        if !readiness.any_ready() {
+        if *this.pending != 0 && !readiness.any_ready() {
             // Nothing is ready yet
             return Poll::Pending;
         }
@@ -193,6 +193,15 @@ mod test {
         });
     }
 
+    #[test]
+    fn empty() {
+        futures_lite::future::block_on(async {
+            let data: [future::Ready<()>; 0] = [];
+            let fut = data.join();
+            assert_eq!(fut.await, []);
+        });
+    }
+
     #[test]
     fn debug() {
         let mut fut = [future::ready("hello"), future::ready("world")].join();

diff --git a/src/future/join/vec.rs b/src/future/join/vec.rs
@@ -87,7 +87,7 @@ where
 
         let mut readiness = this.wakers.readiness().lock().unwrap();
         readiness.set_waker(cx.waker());
-        if !readiness.any_ready() {
+        if *this.pending != 0 && !readiness.any_ready() {
             // Nothing is ready yet
             return Poll::Pending;
         }
@@ -187,6 +187,15 @@ mod test {
         });
     }
 
+    #[test]
+    fn empty() {
+        futures_lite::future::block_on(async {
+            let data: Vec<future::Ready<()>> = vec![];
+            let fut = data.join();
+            assert_eq!(fut.await, vec![]);
+        });
+    }
+
     #[test]
     fn debug() {
         let mut fut = vec![future::ready("hello"), future::ready("world")].join();

diff --git a/src/future/try_join/array.rs b/src/future/try_join/array.rs
@@ -95,7 +95,7 @@ where
 
         let mut readiness = this.wakers.readiness().lock().unwrap();
         readiness.set_waker(cx.waker());
-        if !readiness.any_ready() {
+        if *this.pending != 0 && !readiness.any_ready() {
             // Nothing is ready yet
             return Poll::Pending;
         }
@@ -200,6 +200,15 @@ mod test {
         })
     }
 
+    #[test]
+    fn empty() {
+        futures_lite::future::block_on(async {
+            let data: [future::Ready<io::Result<()>>; 0] = [];
+            let res = data.try_join().await;
+            assert_eq!(res.unwrap(), []);
+        });
+    }
+
     #[test]
     fn one_err() {
         futures_lite::future::block_on(async {

diff --git a/src/future/try_join/vec.rs b/src/future/try_join/vec.rs
@@ -96,7 +96,7 @@ where
 
         let mut readiness = this.wakers.readiness().lock().unwrap();
         readiness.set_waker(cx.waker());
-        if !readiness.any_ready() {
+        if *this.pending != 0 && !readiness.any_ready() {
             // Nothing is ready yet
             return Poll::Pending;
         }
@@ -201,6 +201,15 @@ mod test {
         })
     }
 
+    #[test]
+    fn empty() {
+        futures_lite::future::block_on(async {
+            let data: Vec<future::Ready<io::Result<()>>> = vec![];
+            let res = data.try_join().await;
+            assert_eq!(res.unwrap(), vec![]);
+        });
+    }
+
     #[test]
     fn one_err() {
         futures_lite::future::block_on(async {