fix debug robustness

profile.d/debug.sh

@@ -37,7 +37,7 @@
 # ------------------------------------------------------------------------------
 # Display a backtrace
 # Usage: backtrace
-function backtrace()
+backtrace()
 {
     printf "========= Call stack =========\n"
     local i=1 # We begin at 1 to ignore backtrace itself
@@ -52,7 +52,7 @@ function backtrace()
 
 # ------------------------------------------------------------------------------
 # Function to be trapped for errors investigation
-function error()
+error()
 {
     local errcode=$?
     backtrace
@@ -64,10 +64,6 @@ function error()
 # Usage: settrace <--on|--off|--status>
 settrace()
 {
-    local status="off"
-    [[ $(trap -p ERR) ]] && status="on"
-    #trap -p ERR
-
     local PARSED
     PARSED=$(getopt -oh --long help,on,off,status,force -- "$@")
     # shellcheck disable=SC2181 # getopt return code is checked immediately after
@@ -76,7 +72,10 @@ settrace()
         return 1
     fi
     eval set -- "$PARSED"
-    local force=0
+
+    # First pass: gather the requested action and flags. --on, --off and
+    # --status are mutually exclusive; --force only modifies --on.
+    local action="" force=0
     while true; do
         case $1 in
         -h|--help)
@@ -84,34 +83,24 @@ settrace()
             printf "Options:\n"
             printf "\t--on\t\tActivate backtrace generation\n"
             printf "\t--force\t\tForce replacement of existing trap (use with --on)\n"
-            printf "\t--off\t\tDeactivate backtrace generation\n\n"
+            printf "\t--off\t\tDeactivate backtrace generation\n"
+            printf "\t--status\tDisplay whether the ERR trap is set\n\n"
             printf "That function active a trap event on error. If the script you want to\n"
             printf "debug overload the ERR bash trap, it will not work.\n"
             return 0
             ;;
-        --on)
-            if [[ ${status} == "on" ]] && [[ $force -eq 0 ]]; then
-                disp E "ERR signal trap is already set. Use --force to replace it."
+        --on|--off|--status)
+            if [[ -n $action ]]; then
+                disp E "The --on, --off and --status options are mutually exclusive."
                 return 1
             fi
-            trap "error" ERR
+            action="${1#--}"
             shift
             ;;
         --force)
             force=1
             shift
             ;;
-        --off)
-            if [[ ${status} != "on" ]]; then
-                disp W "ERR signal trap is already unset!"
-            fi
-            trap - ERR
-            shift
-            ;;
-        --status)
-            disp I "Trap signal is ${status}."
-            shift
-            ;;
         --)
             shift
             break
@@ -119,10 +108,36 @@ settrace()
         *)
             disp E "Invalid options, use \"settrace --help\" to display usage."
             return 1
-            ;; 
+            ;;
         esac
     done
-    unset status force
+
+    # Second pass: evaluate the current trap state, then apply the action.
+    local status="off"
+    [[ -n $(trap -p ERR) ]] && status="on"
+
+    case $action in
+    on)
+        if [[ $status == "on" && $force -eq 0 ]]; then
+            disp E "ERR signal trap is already set. Use --force to replace it."
+            return 1
+        fi
+        set -o errtrace
+        trap "error" ERR
+        ;;
+    off)
+        [[ $status != "on" ]] && disp W "ERR signal trap is already unset!"
+        trap - ERR
+        set +o errtrace
+        ;;
+    status)
+        disp I "Trap signal on error is ${status}."
+        ;;
+    "")
+        disp E "No action specified, use \"settrace --help\" to display usage."
+        return 1
+        ;;
+    esac
 }
 export -f settrace
 # ------------------------------------------------------------------------------