-# meant to be sourced. copy/pasted from https://iankelling.org/git/?p=errhandle;a=summary
-
-bash-trace() {
- local -i argc_index=0 arg frame i start=${1:-1} max_indent=8 indent
- local source
- local extdebug=false
- if [[ $(shopt -p extdebug) == *-s* ]]; then
- extdebug=true
- fi
-
- for ((frame=0; frame < ${#FUNCNAME[@]}-1; frame++)); do
- argc=${BASH_ARGC[frame]}
- argc_index+=$argc
- ((frame < start)) && continue
- if (( ${#BASH_SOURCE[@]} > 1 )); then
- source="${BASH_SOURCE[frame+1]}:${BASH_LINENO[frame]}:"
- fi
- indent=$((frame-start+1))
- indent=$((indent < max_indent ? indent : max_indent))
- printf "%${indent}s↳%sin \`%s" '' "$source" "${FUNCNAME[frame]}"
- if $extdebug; then
- for ((i=argc_index-1; i >= argc_index-argc; i--)); do
- printf " %s" "${BASH_ARGV[i]}"
- done
- fi
- echo \'
- done
+#!/bin/bash
+# Bash Error Handler
+# Copyright (C) 2020 Ian Kelling <ian@iankelling.org>
+# SPDX-License-Identifier: GPL-3.0-or-later
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+
+# This is a single file library, just source this file. When an error
+# happens, we print a stack trace then exit. In an interactive shell, we
+# return from functions instead of exiting. If err-cleanup is a command,
+# it runs before the stack trace. Functions are documented inline below
+# for additional use cases.
+#
+# Note: occasionally the line numbers are off a bit (at least in Bash
+# 5.0). This appears to be a bash bug. I plan to report it next time it
+# happens to me.
+#
+# Please email me if you use this or have anything to contribute. I'm
+# not aware of any users yet Ian Kelling <ian@iankelling.org>.
+#
+# Tested on bash 4.4.20(1)-release (x86_64-pc-linux-gnu) and
+# 5.0.17(1)-release (x86_64-pc-linux-gnu).
+#
+# Related: see my bash script template repo at https://iankelling.org/git.
+
+
+# TODO: investigate to see if we can format output betting in case of
+# subshell failure. Right now, we get independent trace from inside and
+# outside of the subshell. Note, errexit + inherit_errexit doesn't have
+# any smarts around this either.
+
+if ! test "$BASH_VERSION"; then echo "error: shell is not bash" >&2; exit 1; fi
+
+#######################################
+# err-catch: Setup trap on ERR to print stack trace and exit (or return
+# if the shell is interactive). This is the most common use case so we
+# run it after defining it, you can call err-allow to undo that.
+#
+# This also sets pipefail because it's a good practice to catch more
+# errors.
+#
+# Note: In interactive shell, stack calling line number is not
+# available, so we print function definition lines.
+#
+# Note: This works like set -e, which has one unintuitive feature: If
+# you use a function as part of a conditional, eg: func && come_cmd, a
+# failed command within func won't trigger an error.
+#
+# Globals
+#
+# err_catch_ignore Array containing glob patterns to test against
+# filenames to ignore errors from in interactive
+# shell. Initialized to ignore bash-completion
+# scripts on debian based systems.
+#
+# err-cleanup If set, this command will run just before exiting.
+#
+# _err_func_last Used internally in err-bash-trace-interactive
+#
+#######################################
+err-catch() {
+ set -E;
+ if [[ $- == *i* ]]; then
+ if ! test ${err_catch_ignore+defined}; then
+ err_catch_ignore=(
+ '/etc/bash_completion.d/*'
+ '*/bash-completion/*'
+ )
+ fi
+ declare -i _err_func_last=0
+ if [[ $- != *c* ]]; then
+ shopt -s extdebug
+ fi
+ # shellcheck disable=SC2154
+ trap '_err-bash-trace-interactive $? "${PIPESTATUS[*]}" "$BASH_COMMAND" ${BASH_ARGC[0]} "${BASH_ARGV[@]}" || return $?' ERR
+ else
+ # Man bash on exdebug: "If set at shell invocation, arrange to
+ # execute the debugger". We want to avoid that, but I want this file
+ # to be sourceable from bash startup files. noninteractive ssh and
+ # sources .bashrc on invocation. login_shell sources things on
+ # invocation.
+ #
+ # extdebug allows us to print function arguments in our stack trace.
+ if ! shopt login_shell >/dev/null && [[ ! $SSH_CONNECTION ]]; then
+ shopt -s extdebug
+ fi
+ trap err-exit ERR
+ fi
+ set -o pipefail