make schedule a kwarg and test default values

Author: jrevels

base/threads_overloads.jl

@@ -1,8 +1,8 @@
 # This file is a part of Julia. License is MIT: https://julialang.org/license
 
 """
-    Threads.foreach(f, channel::Channel,
-                    schedule::Threads.AbstractSchedule=Threads.FairSchedule();
+    Threads.foreach(f, channel::Channel;
+                    schedule::Threads.AbstractSchedule=Threads.FairSchedule(),
                     ntasks=Threads.nthreads())
 
 Similar to `foreach(f, channel)`, but iteration over `channel` and calls to
@@ -23,8 +23,8 @@ with other multithreaded workloads.
 !!! compat "Julia 1.6"
     This function requires Julia 1.6 or later.
 """
-function Threads.foreach(f, channel::Channel,
-                         schedule::Threads.AbstractSchedule=Threads.FairSchedule();
+function Threads.foreach(f, channel::Channel;
+                         schedule::Threads.AbstractSchedule=Threads.FairSchedule(),
                          ntasks=Threads.nthreads())
     apply = _apply_for_schedule(schedule)
     stop = Threads.Atomic{Bool}(false)

test/threads_exec.jl

@@ -853,7 +853,7 @@ function jitter_channel(f, k, delay, ntasks, schedule)
             iseven(i) && sleep(delay)
             put!(ch, f(i))
         end
-        Threads.foreach(g, x, schedule; ntasks=ntasks)
+        Threads.foreach(g, x; schedule=schedule, ntasks=ntasks)
     end
     return y
 end
@@ -873,4 +873,10 @@ end
     @test expected != unordered_static
     @test Set(expected) == Set(unordered_fair)
     @test Set(expected) == Set(unordered_static)
+
+    ys = Channel() do ys
+        inner = Channel(xs -> foreach(i -> put!(xs, i), 1:3))
+        Threads.foreach(x -> put!(ys, x), inner)
+    end
+    @test sort!(collect(ys)) == 1:3
 end