Explicitly kill dynamic children in supervisors

According to the supervisor's documentation:
  "Important note on simple-one-for-one supervisors: The dynamically
   created child processes of a simple-one-for-one supervisor are not
   explicitly killed, regardless of shutdown strategy, but are expected
   to terminate when the supervisor does (that is, when an exit signal
   from the parent process is received)."

All is fine as long as we stop simple_one_for_one supervisor manually.
Dynamic children catch the exit signal from the supervisor and leave.
But, if this happens when we stop an application, after the top
supervisor has stopped, the application master kills all remaining
processes associated to this application. So, dynamic children that trap
exit signals can be killed during their cleanup (here we mean inside
terminate/2). This is unpredictable and highly time-dependent.

In this commit, supervisor module is patched to explicitly terminate
dynamic children accordingly to the shutdown strategy.

NOTE: Order in which dynamic children are stopped is not defined. In
fact, this is "almost" done at the same time.

1 files changed, 0 insertions, 6 deletions

diff --git a/lib/stdlib/doc/src/supervisor.xml b/lib/stdlib/doc/src/supervisor.xml
index edd119d37a..b4e81aba1f 100644
--- a/lib/stdlib/doc/src/supervisor.xml
+++ b/lib/stdlib/doc/src/supervisor.xml
@@ -171,12 +171,6 @@ child_spec() = {Id,StartFunc,Restart,Shutdown,Type,Modules}
         <p>If the child process is another supervisor, <c>Shutdown</c>
           should be set to <c>infinity</c> to give the subtree ample
           time to shutdown.</p>
-        <p><em>Important note on simple-one-for-one supervisors:</em>
-          The dynamically created child processes of a
-          simple-one-for-one supervisor are not explicitly killed,
-          regardless of shutdown strategy, but are expected to terminate
-          when the supervisor does (that is, when an exit signal from
-          the parent process is received).</p>
         <p>Note that all child processes implemented using the standard
           OTP behavior modules automatically adhere to the shutdown
           protocol.</p>