exec 3>&4

poc

@@ -47,14 +47,14 @@ function is_true {
 # HINT: define an alias to bypass ARG evaluation when unnecessary!
 # example: alias toto="bash -c \"[[ \\\$MIAOU_DEBUG == 'true' ]] && echo yes \\\$* || echo nope\""
 function miaou_debug {
-  is_true "${MIAOU_DEBUG}" && >/dev/tty builtin echo -e "\e[90m <== DEBUG ==> \e[33m$*\e[0m" || true
+  is_true "${MIAOU_DEBUG}" && >&4 builtin echo -e "\e[90m <== DEBUG ==> \e[33m$*\e[0m" || true
 }
 
 function tty_ansi {
   local code
   for code in "$@"; do
     if [[ -v ANSI[$code] ]]; then
-      >/dev/tty echo -ne "\e[${ANSI[$code]}m"
+      >&4 echo -ne "\e[${ANSI[$code]}m"
     else
       >&2 echo "unknown ansi key: <$code>"
       break
@@ -70,7 +70,7 @@ function print_miaou_error {
 
 function on_error {
   failure_code="${1:-200}"
-  >/dev/tty printf '\r' # force carriage return explicitly
+  >&4 printf '\r' # force carriage return explicitly
 
   if [[ $$ == "$BASHPID" ]]; then
     miaou_debug "<on_error exit=$failure_code/>"
@@ -214,8 +214,8 @@ function on_exit {
   fi
 
   if [[ -v failure_type ]]; then
-    2>&3 >/dev/tty dump_failure
-    2>&3 >/dev/tty dump_stacktrace
+    2>&3 >&4 dump_failure
+    2>&3 >&4 dump_stacktrace
   fi
 
   miaou_debug "</source type=failure exit=$code pid=${BASHPID}>"
@@ -234,8 +234,11 @@ trap 'on_error $?' ERR
 trap 'on_exit $?' EXIT
 trap 'on_pipe' PIPE
 
+# exec 4>/dev/tty
+[[ -e /proc/$$/fd/3 ]] && exec 4>&3 3>&- || exec 4>/dev/tty
+exec 3>/dev/stderr 2>"$MIAOU_BASH_ERROR"
+
 miaou_debug "<source from=$BASH_ARGV0 pid=${BASHPID}>"
-exec 3>/dev/stderr
 # shellcheck source=/dev/null
-2>"$MIAOU_BASH_ERROR" source "$BASH_ARGV0"
+source "$BASH_ARGV0"
 miaou_debug "</source type=success pid=${BASHPID}>"