From 8f26db138ab62c5ac02c9e454514fc36fb38886e Mon Sep 17 00:00:00 2001
From: Ricardo Pardini <ricardo@pardini.net>
Date: Sun, 9 Oct 2022 17:32:20 +0200
Subject: [PATCH] armbian-next: traps: don't duplicate error message/stacktrace
 when error occurs in subshell; instead indicate clearly `SUBSHELL`

---
 lib/functions/logging/traps.sh | 16 +++++++++++++---
 1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/lib/functions/logging/traps.sh b/lib/functions/logging/traps.sh
index e897171e6a..b9b46601d4 100644
--- a/lib/functions/logging/traps.sh
+++ b/lib/functions/logging/traps.sh
@@ -34,7 +34,7 @@ function main_trap_handler() {
 	stack_caller="$(show_caller_full)"
 	short_stack="${BASH_SOURCE[1]}:${BASH_LINENO[0]}"
 
-	display_alert "main_trap_handler" "${trap_type} and ${trap_exit_code} trap_manager_error_handled:${trap_manager_error_handled}" "trap"
+	display_alert "main_trap_handler" "${trap_type} and ${trap_exit_code} trap_manager_error_handled:${trap_manager_error_handled} short_stack:${short_stack}" "trap"
 
 	case "${trap_type}" in
 		TERM | INT)
@@ -44,8 +44,18 @@ function main_trap_handler() {
 			;;
 
 		ERR)
-			logging_error_show_log
-			display_alert "Error occurred" "code ${trap_exit_code} at ${short_stack}\n${stack_caller}\n" "err"
+			# If error occurs in subshell (eg: inside $()), we would show the error twice.
+			# Determine if we're in a subshell, and if so, output a single message.
+			# BASHPID is the current subshell; $$ is parent shell pid
+			if [[ "${BASHPID}" == "${$}" ]]; then
+				# Not in subshell, dump the error, complete with log, and show the stack.
+				logging_error_show_log
+				display_alert "Error occurred in main shell" "code ${trap_exit_code} at ${short_stack}\n${stack_caller}\n" "err"
+			else
+				# In a subshell. This trap will run again in the parent shell, so just output a message about it;
+				# When the parent shell trap runs, it will show the stack and log.
+				display_alert "Error occurred in SUBSHELL" "SUBSHELL: code ${trap_exit_code} at ${short_stack}" "err"
+			fi
 			trap_manager_error_handled=1
 			return # Nothing else to do here, let the EXIT trap do the cleanups.
 			;;