return

_stderr

@@ -0,0 +1,9 @@
+some trace in stderr
+This is stderr
+ERROR 10: <undefined>
+	            lib/utility.bash:7	suite
+	            lib/utility.bash:3	blabla
+	                  useless.sh:8	F2
+	                 useless.sh:19	F1
+	                 useless.sh:23	main
+	                 useless.sh:35	<main>

_stdout

@@ -0,0 +1,5 @@
+start of useless
+F3
+F1
+stdout A
+IN blabla OUT

bin/bash-back

@@ -7,12 +7,28 @@ SCRIPT=$1
 
 # FUNCTIONS
 
+# overridden function which permits stacktracing of original `return` statement
 function return {
-  builtin return ${1:-}
+  code=${1:-0}
+  [[ $code -gt 0 ]] && >&2 echo "${BASH_SOURCE[2]}: line ${BASH_LINENO[0]}: return $@"
+  builtin return $code
 }
 
+# # overridden function which permits stacktracing of original `return` statement
+# function exit {
+#   code=${1:-0}
+#   if [[ $code -gt 0 ]]; then
+#     >/dev/stderr echo "${BASH_SOURCE[2]}: line ${BASH_LINENO[0]}: exit $@"
+#     on_exit $code
+#     builtin exit $code
+#   else
+#     success
+#   fi
+# }
+
 function exit {
   code=${1:-0}
+  >&4 dump_stderr
 
   stack_lines=("${BASH_LINENO[@]}")
   stack_functions=("${FUNCNAME[@]}")
@@ -28,38 +44,51 @@ function exit {
   stack_functions=("${stack_functions[@]}")
   stack_sources=("${stack_sources[@]}")
 
-  if [[ -s $TMP_ERROR ]]; then
+  if [[ $code -gt 0 ]]; then
+    $DEBUG && >/dev/tty echo '---stacktrace---'
     last_error=$(tail -n1 $TMP_ERROR)
-    $DEBUG && >/dev/tty echo '---stderr---'
-    >&4 echo "ERROR $code: [$last_error]"
+    last_source=${stack_sources[0]}
+    last_source=${last_source//./"\."} # replace . by \.
+    regex="^$last_source: line ([0-9]+): (.*)$"
+    if [[ "$last_error" =~ $regex ]]; then
+      line=${BASH_REMATCH[1]}
+      message=${BASH_REMATCH[2]}
+      regex=': unbound variable$'
+      [[ $code == 1 ]] && [[ "$message" =~ $regex ]] && stack_lines[0]=$line
+      >&4 echo -e "ERROR $code: [$message]"
+    else
+      >&4 echo "ERROR $code: <undefined>"
     fi
 
     for i in "${!stack_functions[@]}"; do
       >&4 printf "\t%30s\t%s\n" "${stack_sources[$i]}:${stack_lines[$i]}" "${stack_functions[$i]}"
     done
+  fi
 
   # echo "${stack_lines[@]}"
   # echo "${stack_functions[@]}"
   # echo "${stack_sources[@]}"
 
-  cleanup ${code}
+  cleanup
+  builtin exit $code
 }
 
-function success {
+function dump_stderr {
   if [[ -s $TMP_ERROR ]]; then
     $DEBUG && >/dev/tty echo '---stderr---'
-    >&2 cat $TMP_ERROR
+    cat $TMP_ERROR
   fi
-  cleanup 0
+}
+
+function success {
+  >&2 dump_stderr
+  cleanup
 }
 
 function cleanup {
-  code=${1:-0}
-  $DEBUG && >/dev/tty echo "---exit $1---"
   trap - ERR TERM INT EXIT
-  rm $TMP_ERROR
   exec 3>&- 4>&-
-  builtin exit $code
+  rm $TMP_ERROR
 }
 
 # MAIN

lib/utility.bash

@@ -4,6 +4,7 @@ function blabla {
 }
 
 function suite {
+  exit 10
   return 7
   echo $nope
   command_not_found

useless.sh

@@ -4,10 +4,11 @@ function F2 {
   echo "stdout A"
   # echo toto >>/tmp/toto
   >&2 echo "This is stderr"
+
   blabla
+  $nope
   exit 6
   grep titi toto
-  $nope
   echo "stdout B"
   echo "stdout C"
   # command_not_found
@@ -22,7 +23,14 @@ function main {
   F1
 }
 
-. lib/utility.bash
+function F3 {
+  echo F3
+  return 0
+}
+
 echo start of useless
+F3
+. lib/utility.bash
+>&2 echo some trace in stderr
 main
 echo end of useless