Work-around for #546

If the `reason` passed to `__lumen_builtin_error` is a 2-tuple of `{Class, Reason}` where `Class` is `error` or `exit`, exit the process with just `Reason`.

Author: KronicDeth

native_implemented/otp/tests/lib/erlang/link_1/with_local_pid/when_a_linked_process_does_not_exit_normal_the_process_exits_too/init.erl

@@ -20,8 +20,7 @@ start() ->
     end
   end),
   receive
-    %% FIXME https://github.com/lumen/lumen/issues/546
-    {'DOWN', ParentMonitorReference, process, _, {exit, Reason}} ->
+    {'DOWN', ParentMonitorReference, process, _, Reason} ->
       display({parent, exited, Reason});
     10 ->
       display({parent, alive, is_process_alive(ParentPid)})

native_implemented/otp/tests/lib/erlang/link_1/with_local_pid/when_the_process_does_not_exit_normal_linked_processes_exit_too/init.erl

@@ -20,15 +20,13 @@ start() ->
       ChildMonitorReference = monitor(process, ChildPid),
       shutdown(ParentPid),
       receive
-        %% FIXME https://github.com/lumen/lumen/issues/546
-        {'DOWN', ParentMonitorReference, process, _, {exit, Reason1}} ->
+        {'DOWN', ParentMonitorReference, process, _, Reason1} ->
           display({parent, exited, Reason1})
       after 10 ->
         display({parent, alive, is_process_alive(ParentPid)})
       end,
       receive
-        %% FIXME https://github.com/lumen/lumen/issues/546
-        {'DOWN', ChildMonitorReference, process, _, {exit, Reason2}} ->
+        {'DOWN', ChildMonitorReference, process, _, Reason2} ->
           display({child, exited, Reason2})
       after 10 ->
         display({child, alive, is_process_alive(ChildPid)})

native_implemented/otp/tests/lib/erlang/process_flag_2/with_atom_flag/with_trap_exit_flag.rs

@@ -6,11 +6,11 @@ test_stdout!(
 );
 test_stdout!(
     with_true_value_with_linked_and_does_not_exit_when_linked_process_exits_normal,
-    "{trap_exit, true}\n{parent, alive, true}\n{child, alive, false}\n"
+    "{trap_exit, true}\n{parent, alive, true}\n{child, exited, normal}\n"
 );
 test_stdout!(
     with_true_value_with_linked_receive_exit_message_and_does_not_exit_when_linked_process_does_not_exit_normal,
-    "{trap_exit, true}\n{parent, sees, child, exit, due, to, abnormal}\n{parent, alive, true}\n{child, exited, abnormal}\n"
+    "{trap_exit, true}\n{parent, alive, true}\n{child, exited, abnormal}\n{parent, sees, child, alive, false}\n"
 );
 test_stdout!(
     with_true_value_then_false_value_exits_when_linked_process_does_not_exit_normal,

native_implemented/otp/tests/lib/erlang/process_flag_2/with_atom_flag/with_trap_exit_flag/with_true_value_then_false_value_exits_when_linked_process_does_not_exit_normal/init.erl

@@ -25,15 +25,13 @@ end),
       ChildMonitorReference = monitor(process, ChildPid),
       shutdown(ParentPid),
       receive
-      %% FIXME https://github.com/lumen/lumen/issues/546
-        {'DOWN', ParentMonitorReference, process, _, {exit, Reason1}} ->
+        {'DOWN', ParentMonitorReference, process, _, Reason1} ->
           display({parent, exited, Reason1})
       after 10 ->
         display({parent, alive, is_process_alive(ParentPid)})
       end,
       receive
-      %% FIXME https://github.com/lumen/lumen/issues/546
-        {'DOWN', ChildMonitorReference, process, _, {exit, Reason2}} ->
+        {'DOWN', ChildMonitorReference, process, _, Reason2} ->
           display({child, exited, Reason2})
       after 10 ->
         display({child, alive, is_process_alive(ChildPid)})

native_implemented/otp/tests/lib/erlang/process_flag_2/with_atom_flag/with_trap_exit_flag/with_true_value_with_linked_and_does_not_exit_when_linked_process_exits_normal/init.erl

@@ -22,15 +22,13 @@ start() ->
       ChildMonitorReference = monitor(process, ChildPid),
       shutdown_child(ParentPid),
       receive
-      %% FIXME https://github.com/lumen/lumen/issues/546
-        {'DOWN', ParentMonitorReference, process, _, {exit, Reason1}} ->
+        {'DOWN', ParentMonitorReference, process, _, Reason1} ->
           display({parent, exited, Reason1})
       after 10 ->
         display({parent, alive, is_process_alive(ParentPid)})
       end,
       receive
-      %% FIXME https://github.com/lumen/lumen/issues/546
-        {'DOWN', ChildMonitorReference, process, _, {exit, Reason2}} ->
+        {'DOWN', ChildMonitorReference, process, _, Reason2} ->
           display({child, exited, Reason2})
       after 10 ->
         display({child, alive, is_process_alive(ChildPid)})

native_implemented/otp/tests/lib/erlang/process_flag_2/with_atom_flag/with_trap_exit_flag/with_true_value_with_linked_receive_exit_message_and_does_not_exit_when_linked_process_does_not_exit_normal/init.erl

@@ -29,15 +29,13 @@ start() ->
       ChildMonitorReference = monitor(process, ChildPid),
       shutdown_child(ParentPid),
       receive
-      %% FIXME https://github.com/lumen/lumen/issues/546
-        {'DOWN', ParentMonitorReference, process, _, {exit, Reason1}} ->
+        {'DOWN', ParentMonitorReference, process, _, Reason1} ->
           display({parent, exited, Reason1})
       after 10 ->
         display({parent, alive, is_process_alive(ParentPid)})
       end,
       receive
-      %% FIXME https://github.com/lumen/lumen/issues/546
-        {'DOWN', ChildMonitorReference, process, _, {exit, Reason2}} ->
+        {'DOWN', ChildMonitorReference, process, _, Reason2} ->
           display({child, exited, Reason2})
       after 10 ->
         display({child, alive, is_process_alive(ChildPid)})

native_implemented/otp/tests/lib/erlang/spawn_1/with_function/without_arity_zero_returns_pid_to_parent_and_child_process_exits_badarity/init.erl

@@ -12,7 +12,8 @@ start() ->
   receive
     {'DOWN', MonitorRef, process, _, Info} ->
       case Info of
-        {error, {Reason, _Stacktrace}} -> display(Reason);
+        %% FIXME https://github.com/lumen/lumen/issues/548
+        {Reason, FunArgs} -> display(Reason);
         Other -> display(Other)
       end
     after 20 ->

native_implemented/otp/tests/lib/erlang/spawn_link_1/with_function/with_arity_zero/with_environment/without_normal_exit_in_child_process_exits_linked_parent_process/init.erl

@@ -23,8 +23,7 @@ start() ->
     ok
   end),
   receive
-    %% FIXME https://github.com/lumen/lumen/issues/546
-    {'DOWN', ParentMonitorReference, process, _, {exit, Reason}} ->
+    {'DOWN', ParentMonitorReference, process, _, Reason} ->
       display({parent, Reason})
   after
     100 ->

native_implemented/otp/tests/lib/erlang/spawn_link_1/with_function/with_arity_zero/without_environment/without_normal_exit_in_child_process_exits_linked_parent_process/init.erl

@@ -22,8 +22,7 @@ start() ->
     ok
   end),
   receive
-    %% FIXME https://github.com/lumen/lumen/issues/546
-    {'DOWN', ParentMonitorReference, process, _, {exit, Reason}} ->
+    {'DOWN', ParentMonitorReference, process, _, Reason} ->
       display({parent, Reason})
   after
     100 ->

native_implemented/otp/tests/lib/erlang/spawn_link_1/with_function/without_arity_zero_returns_pid_to_parent_and_child_process_exits_badarity_which_exits_linked_parent/init.erl

@@ -22,8 +22,7 @@ start() ->
     ok
   end),
   receive
-    %% FIXME https://github.com/lumen/lumen/issues/546
-    {'DOWN', ParentMonitorReference, process, _, {error, Info}} ->
+    {'DOWN', ParentMonitorReference, process, _, Info} ->
       case Info of
         {badarity = Reason, FunArgs} ->
           display({parent, Reason});

native_implemented/otp/tests/lib/erlang/spawn_monitor_1/with_function/with_arity_zero/with_environment/with_normal_exit_in_child_process_sends_exit_message_to_parent/init.erl

@@ -10,8 +10,7 @@ start() ->
     exit(Environment)
   end),
   receive
-    %% FIXME https://github.com/lumen/lumen/issues/546
-    {'DOWN', ChildMonitorReference, process, _, {exit, Reason}} ->
+    {'DOWN', ChildMonitorReference, process, _, Reason} ->
       display({child, exited, Reason})
     after 10 ->
       display(timeout)

native_implemented/otp/tests/lib/erlang/spawn_monitor_1/with_function/with_arity_zero/with_environment/without_normal_exit_in_child_process_sends_exit_message_to_parent/init.erl

@@ -10,8 +10,7 @@ start() ->
     exit(Environment)
   end),
   receive
-    %% FIXME https://github.com/lumen/lumen/issues/546
-    {'DOWN', ChildMonitorReference, process, _, {exit, Reason}} ->
+    {'DOWN', ChildMonitorReference, process, _, Reason} ->
       display({child, exited, Reason})
     after 10 ->
       display(timeout)

native_implemented/otp/tests/lib/erlang/spawn_monitor_1/with_function/with_arity_zero/without_environment/without_normal_exit_in_child_process_sends_exit_message_to_parent/init.erl

@@ -9,8 +9,7 @@ start() ->
     exit(abnormal)
   end),
   receive
-    %% FIXME https://github.com/lumen/lumen/issues/546
-    {'DOWN', ChildMonitorReference, process, _, {exit, Reason}} ->
+    {'DOWN', ChildMonitorReference, process, _, Reason} ->
       display({child, exited, Reason})
     after 10 ->
       display(timeout)

native_implemented/otp/tests/lib/erlang/spawn_monitor_1/with_function/without_arity_zero_returns_pid_to_parent_and_child_process_exits_badarity_and_sends_exit_message_to_parent/init.erl

@@ -9,8 +9,7 @@ start() ->
     display(A)
   end),
   receive
-    %% FIXME https://github.com/lumen/lumen/issues/546
-    {'DOWN', ChildMonitorReference, process, _, {error, {Reason, Details}}} ->
+    {'DOWN', ChildMonitorReference, process, _, {Reason, Details}} ->
       display({child, exited, Reason})
     after 10 ->
       display(timeout)

runtimes/minimal/src/scheduler.rs

@@ -75,12 +75,40 @@ pub unsafe extern "C" fn process_exit(reason: Term) {
         .as_any()
         .downcast_ref::<Scheduler>()
         .unwrap();
+    // FIXME https://github.com/lumen/lumen/issues/546
+    let exit_reason = work_around546(reason);
+
     scheduler
         .current
-        .exit(reason, anyhow!("process exit").into());
+        .exit(exit_reason, anyhow!("process exit").into());
     scheduler.process_yield();
 }
 
+// Work-around:  Unwrap `{class, reason}`, but it means that processes can't exit with a reason
+// that looks like `{class, reason}.
+fn work_around546(reason: Term) -> Term {
+    match reason.decode().unwrap() {
+        TypedTerm::Tuple(boxed_tuple) => {
+            let elements = boxed_tuple.elements();
+
+            if elements.len() == 2 {
+                let class = elements[0];
+
+                match class.decode().unwrap() {
+                    TypedTerm::Atom(class_atom) => match class_atom.name() {
+                        "error" | "exit" => elements[1],
+                        _ => reason,
+                    },
+                    _ => reason,
+                }
+            } else {
+                reason
+            }
+        }
+        _ => reason,
+    }
+}
+
 #[naked]
 #[inline(never)]
 #[cfg(all(unix, target_arch = "x86_64"))]