#!/bin/bash
-# Copyright 2018 Ian Kelling
-
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-
-# http://www.apache.org/licenses/LICENSE-2.0
-
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
+# Copyright (C) 2019 Ian Kelling
+# SPDX-License-Identifier: GPL-3.0-or-later
# Commentary: Bash stack trace and error handling functions. This file
# is meant to be sourced. It loads some functions which you may want to
# call manually (see the comments at the start of each one), and then
# runs err-catch. See the README file for a slightly longer explanation.
-err-allow() {
- # help: turn off exit and stack trace on error. undoes err-catch
- set +E +o pipefail; trap ERR
-}
+#######################################
+# Print stack trace
+#
+# usage: err-bash-trace [MESSAGE]
+#
+# This function is called by the other functions which print stack
+# traces.
+#
+# It does not show function args unless you first run:
+# shopt -s extdebug
+# which err-catch & err-print do for you.
+#
+# MESSAGE Message to print just before the stack trace.
+#
+# _frame_start Optional variable to set before calling. The frame to
+# start printing on. default=1. Useful when printing from
+# an ERR trap function to avoid printing that function.
+#######################################
err-bash-trace() {
- # help: print stack trace
- #
- # Note: It does not show function args unless you first run:
- # shopt -s extdebug
- # err-catch runs this for you.
-
- local -i argc_index=0 frame i start=${1:-1} max_indent=8 indent
+ local -i argc_index=0 frame i start=${_frame_start:-1}
local source
- local extdebug=false
- if [[ $(shopt -p extdebug) == *-s* ]]; then
- extdebug=true
+ if [[ $1 ]]; then
+ printf "%s\n" "$1"
fi
- for ((frame=0; frame < ${#FUNCNAME[@]}-1; frame++)); do
+ for ((frame=0; frame < ${#FUNCNAME[@]}; frame++)); do
argc=${BASH_ARGC[frame]}
argc_index+=$argc
((frame < start)) && continue
if (( ${#BASH_SOURCE[@]} > 1 )); then
- source="${BASH_SOURCE[frame+1]}:${BASH_LINENO[frame]}:"
+ source="${BASH_SOURCE[frame]}:${BASH_LINENO[frame-1]}:"
fi
- indent=$((frame-start+1))
- indent=$((indent < max_indent ? indent : max_indent))
- printf "%${indent}s↳%sin \`%s" '' "$source" "${FUNCNAME[frame]}"
- if $extdebug; then
+ printf " from %sin \`%s" "$source" "${FUNCNAME[frame]}"
+ if shopt extdebug >/dev/null; then
for ((i=argc_index-1; i >= argc_index-argc; i--)); do
printf " %s" "${BASH_ARGV[i]}"
done
fi
echo \'
done
+ return 0
}
+#######################################
+# On error print stack trace and exit
+#
+# Globals:
+# errcatch-cleanup If set, this command will run just before exiting.
+#######################################
err-catch() {
- # help: on errors: print stack trace and exit
+ set -E;
+ # This condition avoids starting the bash debugger in the case that
+ # this is sourced from a startup file, and you use a login shell to
+ # run a command. eg: bash -l some-command. Avoid doing that if you want
+ # function arguments in your trace.
+ if ! shopt login_shell >/dev/null; then
+ shopt -s extdebug
+ fi
+ _err-trap() {
+ err=$?
+ exec >&2
+ set +x
+ local msg="${BASH_SOURCE[1]}:${BASH_LINENO[0]}: \`$BASH_COMMAND' returned $err"
+ if (( ${#FUNCNAME[@]} > 2 )); then
+ local _frame_start=2
+ err-bash-trace "$msg"
+ else
+ echo "$msg"
+ fi
+ set -e # err trap does not work within an error trap
+ if type -t errcatch-cleanup >/dev/null; then
+ errcatch-cleanup
+ fi
+ echo "$0: exiting with status $err"
+ exit $err
+ }
+ trap _err-trap ERR
+ set -o pipefail
+}
+
+
+#######################################
+# Internal function for err-catch-interactive.
+# Prints stack trace from interactive shell trap.
+# Usage: see err-catch-interactive
+#######################################
+
+_err-bash-trace-interactive() {
+ if (( ${#FUNCNAME[@]} <= 1 )); then
+ return 0
+ fi
+
+ for pattern in "${err_catch_ignore[@]}"; do
+ # shellcheck disable=SC2053
+ if [[ ${BASH_SOURCE[1]} == $pattern ]]; then
+ return 0
+ fi
+ done
+
+ local ret bash_command argc pattern i last
+ last=$_err_func_last
+ _err_func_last=${#FUNCNAME[@]}
+ # We have these passed to us because they are lost inside the
+ # function.
+ ret=$1
+ bash_command="$2"
+ argc=$(( $3 - 1 ))
+ shift 3
+ argv=("$@")
+ # The trap returns a nonzero, then gets called again. This condition
+ # tells us if we are the first.
+ if (( _err_func_last > last )); then
+ echo ERR: \`$bash_command\' returned $ret
+ fi
+ printf " from \`%s" "${FUNCNAME[1]}"
+ if shopt extdebug >/dev/null; then
+ for ((i=argc; i >= 0; i--)); do
+ printf " %s" "${argv[i]}"
+ done
+ fi
+ printf "\' defined at %s:%s\n" "${BASH_SOURCE[1]}" "$(declare -F "${FUNCNAME[1]}"|awk "{print \$2}")"
+ return $ret
+}
+
+#######################################
+# For interactive shells: on error, print stack trace and return
+#
+# Note: calling line number is not available, so we print function
+# definition lines.
+#
+# Globals:
+# err_catch_ignore Array containing glob patterns to test against filenames to ignore
+# errors from. Initialized to ignore bash-completion scripts on debian
+# based systems.
+# _err_func_last Used internally in err-bash-trace-interactive
+#
+#######################################
+err-catch-interactive() {
+ if ! test ${err_catch_ignore+defined}; then
+ err_catch_ignore=(
+ '/etc/bash_completion.d/*'
+ '*/bash-completion/*'
+ )
+ fi
+ declare -i _err_func_last=0
+ set -E; shopt -s extdebug
+ # shellcheck disable=SC2154
+ trap '_err-bash-trace-interactive $? "$BASH_COMMAND" ${BASH_ARGC[0]} "${BASH_ARGV[@]}" || return $?' ERR
+ set -o pipefail
+}
+
+
+#######################################
+# Undo err-catch/err-catch-interactive
+#######################################
+err-allow() {
+ shopt -u extdebug
+ set +E +o pipefail
+ trap ERR
+}
+
+#######################################
+# On error, print stack trace
+#######################################
+err-print() {
+ # help: on errors: print stack trace
#
- # You can set "${_errcatch_cleanup[@]}" to a command and it will run before exiting.
# This function depends on err-bash-trace.
set -E; shopt -s extdebug
err=$?
exec >&2
set +x
- echo "${BASH_SOURCE[1]}:${BASH_LINENO[0]}:in \`$BASH_COMMAND' returned $err"
- # err trap does not work within an error trap, the following line:
- err-bash-trace 2; set -e
- "${_errcatch_cleanup[@]:-:}" # note :-: is to be compatible with set -u
- echo "$0: exiting with code $err"
- exit $err
+ echo "${BASH_SOURCE[1]}:${BASH_LINENO[0]}: \`$BASH_COMMAND' returned $err"
+ err-bash-trace 2
}
trap _err-trap ERR
set -o pipefail
}
-err-exit() {
- # usage: err-exit [EXIT_CODE] [MESSAGE]
- # help: exit and print stack trace.
- #
- # Use this instead of the exit command to be more informative. default
- # EXIT_CODE is 1. If only one of EXIT_CODE and MESSAGE is given,
- # we consider it to be an exit code if it is a number.
- # This function depends on err-bash-trace.
+#######################################
+# Print stack trace and exit
+#
+# Use this instead of the exit command to be more informative.
+#
+# usage: err-exit [EXIT_CODE] [MESSAGE]
+#
+# EXIT_CODE Default is 1.
+# MESSAGE Print MESSAGE to stderr. If only one of EXIT_CODE
+# and MESSAGE is given, we consider it to be an
+# exit code if it is a number.
+#######################################
+err-exit() {
exec >&2
code=1
if [[ "$*" ]]; then
if [[ ${1/[^0-9]/} == "$1" ]]; then
code=$1
if [[ $2 ]]; then
- printf '%s\n' "$2"
+ printf '%s\n' "$2" >&2
fi
else
- printf '%s\n' "$0: $1"
+ printf '%s\n' "$0: $1" >&2
fi
fi
echo "${BASH_SOURCE[1]}:${BASH_LINENO[0]}"
exit $err
}
-err-catch
+# We want this more often than not, so run it now.
+if [[ $- == *i* ]]; then
+ err-catch-interactive
+else
+ err-catch
+fi