ZSH Completions - parse error near `|' _msm:8: command not found: manager_property

[Next-Door-Tech]

Using ZSH on Debian 10, after loading the BASH completions file in .zshrc, trying to autocomplete msm commands results in an error.

I have ZSH loading the completions file with the following lines at the end of my .zshrc:

autoload -U +X compinit
compinit
autoload -U +X bashcompinit
bashcompinit
source /etc/bash_completion.d/msm

When I try to complete a command by typing

% sudo msm <tab>

I get

% sudo msm /etc/init.d/msm:1199: parse error near `|'
_msm:8: command not found: manager_property
                                 sudo msm
all       config    help      jargroup  restart   server    start     stop      update    version 

Further tab presses allow me to select an option, but further garbage is output to the prompt.

[Next-Door-Tech]

Inspected /etc/init.d/msm at line 1199 and found

if [[ "$answer" =~ ^y|Y|yes$ ]]; then
    as_user "$SETTINGS_USERNAME" "rm -rf \"$SETTINGS_JAR_STORAGE_PATH/$1\""
    echo "Jar group deleted."
else
    echo "Jar group was NOT deleted."
fi

Investigating | chars inside test functions in ZSH

[Next-Door-Tech]

Found changing line 1199
if [[ "$answer" =~ ^y|Y|yes$ ]]; then
to
if [[ "$answer" =~ (^y|Y|yes$) ]]; then
results in a new error referencing line 1796.

Changing
if [[ ! "$arg" =~ logroll|config ]]; then
to
if [[ ! "$arg" =~ (logroll|config) ]]; then
results in a new error when trying to tab complete:

sudo msm server_property:87: bad substitution
                                 sudo msm
all    config    help      jargroup  restart   server    sss       start     stop      update    version 

[Next-Door-Tech]

Found bad substitution error at /etc/init.d/msm line 1847:

if [ -z "${!target_varname}" ]; then
    # if its still empty use the default value
    manager_property "DEFAULT_$2"
    server_set_property "$1" "$2" "\$SETTINGS_DEFAULT_$2"
fi

The error seems to be caused by the ${!target_varname} - ZSH arrays do not output the keys with ${!array}, instead it uses ${(k)array). So the ZSH-friendly version of the first line would be

if [ -z "${(k)target_varname}" ]; then
...

Not sure how to proceed from here without breaking the script.