Bash: How to get the call chain on errors?

Question

I have a back trace function in bash that works well enough (code below) but the problem is that bash itself when it hits an error, it doesn't give a back trace or any kind of info that would help determine the caller, which can help in debugging the issue.

e.g.:

./c.sh: line 23: urgh: command not found

function backtrace () {
    local deptn=${#FUNCNAME[@]}

    for ((i=1; i<$deptn; i++)); do
        local func="${FUNCNAME[$i]}"
        local line="${BASH_LINENO[$((i-1))]}"
        local src="${BASH_SOURCE[$((i-1))]}"
        printf '%*s' $i '' # indent
        echo "at: $func(), $src, line $line"
    done
}

Is it possible to trap bash on such errors so I could call my own function to get output like this?

 at: c(), ./c.sh, line 22
  at: b(), ./c.sh, line 11
   at: main(), ./b.sh, line 5

Update: final working version from suggestions and traceback trap on error:

function backtrace () {
    local deptn=${#FUNCNAME[@]}

    for ((i=1; i<$deptn; i++)); do
        local func="${FUNCNAME[$i]}"
        local line="${BASH_LINENO[$((i-1))]}"
        local src="${BASH_SOURCE[$((i-1))]}"
        printf '%*s' $i '' # indent
        echo "at: $func(), $src, line $line"
    done
}

function trace_top_caller () {
    local func="${FUNCNAME[1]}"
    local line="${BASH_LINENO[0]}"
    local src="${BASH_SOURCE[0]}"
    echo "  called from: $func(), $src, line $line"
}

set -o errtrace
trap 'trace_top_caller' ERR

Answer 1

Absolutely -- this is exactly what error traps are for:

trap backtrace ERR

In the past, I vaguely recall finding it necessary to make that something more like trap 'backtrace "${#BASH_SOURCE[@]}" "${BASH_SOURCE[@]}" "${#BASH_LINENO[@]}" "${BASH_LINENO[@]}"' ERR to work around a bug (and reading array values off the function's argv); however, I don't remember at present just what that bug would be and which versions it impacted.