Support infinity timeout on yield_many, closes #7633

Signed-off-by: José Valim <[email protected]>

Author: José Valim

lib/elixir/lib/task.ex

@@ -648,15 +648,19 @@ defmodule Task do
   @spec yield_many([t], timeout) :: [{t, {:ok, term} | {:exit, term} | nil}]
   def yield_many(tasks, timeout \\ 5000) do
     timeout_ref = make_ref()
-    timer_ref = Process.send_after(self(), timeout_ref, timeout)
+
+    timer_ref =
+      if timeout != :infinity do
+        Process.send_after(self(), timeout_ref, timeout)
+      end
 
     try do
       yield_many(tasks, timeout_ref, :infinity)
     catch
       {:noconnection, reason} ->
         exit({reason, {__MODULE__, :yield_many, [tasks, timeout]}})
     after
-      Process.cancel_timer(timer_ref)
+      timer_ref && Process.cancel_timer(timer_ref)
       receive do: (^timeout_ref -> :ok), after: (0 -> :ok)
     end
   end

lib/elixir/test/elixir/task_test.exs

@@ -323,6 +323,19 @@ defmodule TaskTest do
       assert Task.yield_many([task1, task2, task3], 0) ==
                [{task1, {:ok, :result}}, {task2, nil}, {task3, {:exit, :normal}}]
     end
+
+    test "returns results on infinity timeout" do
+      task1 = %Task{ref: make_ref(), owner: self()}
+      task2 = %Task{ref: make_ref(), owner: self()}
+      task3 = %Task{ref: make_ref(), owner: self()}
+
+      send(self(), {task1.ref, :result})
+      send(self(), {task2.ref, :result})
+      send(self(), {:DOWN, task3.ref, :process, self(), :normal})
+
+      assert Task.yield_many([task1, task2, task3], :infinity) ==
+               [{task1, {:ok, :result}}, {task2, {:ok, :result}}, {task3, {:exit, :normal}}]
+    end
   end
 
   describe "shutdown/2" do