use Pipe for now

stdlib/REPL/src/LineEdit.jl

@@ -366,9 +366,11 @@ end
 # Prompt Completions & Hints
 function complete_line(s::MIState)
     set_action!(s, :complete_line)
-    # don't allow stderr/stdout prints during completion computation
+    # suppress stderr/stdout prints during completion computation
     # i.e. ambiguous qualification warnings that are printed to stderr
-    completions_exist = redirect_stdio(;stderr=devnull, stdout=devnull) do
+    # TODO: remove this suppression once such warnings are better handled
+    # TODO: but before that change Pipe to devnull once devnull redirects work for JL_STDERR etc.
+    completions_exist = redirect_stdio(;stderr=Pipe(), stdout=Pipe()) do
         complete_line(state(s), s.key_repeats, s.active_module)
     end
     if completions_exist
@@ -387,9 +389,11 @@ function check_for_hint(s::MIState)
         # Requires making space for them earlier in refresh_multi_line
         return clear_hint(st)
     end
-    # don't allow stderr/stdout prints during completion computation
+    # suppress stderr/stdout prints during completion computation
     # i.e. ambiguous qualification warnings that are printed to stderr
-    completions, partial, should_complete = redirect_stdio(;stderr=devnull, stdout=devnull) do
+    # TODO: remove this suppression once such warnings are better handled
+    # TODO: but before that change Pipe to devnull once devnull redirects work for JL_STDERR etc.
+    completions, partial, should_complete = redirect_stdio(;stderr=Pipe(), stdout=Pipe()) do
         complete_line(st.p.complete, st, s.active_module; hint = true)::Tuple{Vector{String},String,Bool}
     end
     isempty(completions) && return clear_hint(st)