kernel: Fix group to not crash if group_history fails

There used to be a bug where the AC would block and set_env
would crash. This caused the shell to be unuseable as it crashed
all the time. So we add some safe guards to make sure that does
not happen again.

Author: garazdawi

lib/kernel/src/group.erl

@@ -19,6 +19,8 @@
 %%
 -module(group).
 
+-include_lib("kernel/include/logger.hrl").
+
 %% A group leader process for user io.
 %% This process receives input data from user_drv in this format
 %%   {Drv,{data,unicode:charlist()}}
@@ -1005,7 +1007,12 @@ save_line_buffer("\n", Lines) ->
 save_line_buffer(Line, [Line|_Lines]=Lines) ->
     save_line_buffer(Lines);
 save_line_buffer(Line, Lines) ->
-    group_history:add(Line),
+    try
+        group_history:add(Line)
+    catch E:R:ST ->
+            ?LOG_ERROR(#{ msg => "Failed to write to shell history",
+                          error => {E, R, ST} })
+    end,
     save_line_buffer([Line|Lines]).
 
 save_line_buffer(Lines) ->

lib/kernel/src/group_history.erl

@@ -374,7 +374,10 @@ find_path() ->
 to_drop() ->
     case application:get_env(kernel, shell_history_drop) of
         undefined ->
-            application:set_env(kernel, shell_history_drop, ?DEFAULT_DROP),
+            %% The AC might be overloaded/not responding and
+            %% we want the shell to be as responsive as possible
+            %% so we set a short timeout
+            application:set_env(kernel, shell_history_drop, ?DEFAULT_DROP, [{timeout, 10}]),
             ?DEFAULT_DROP;
         {ok, V} when is_list(V) -> [Ln++"\n" || Ln <- V];
         {ok, _} -> ?DEFAULT_DROP