Completions stopped working after upgrading zsh

Question

Previously I have been using this handy script with oh-my-zsh to set the tab color whenever I ssh into a machine:

# iTerm2 window/tab color commands
#   http://code.google.com/p/iterm2/wiki/ProprietaryEscapeCodes
tab-color() {
    echo -ne "\033]6;1;bg;red;brightness;$1\a"
    echo -ne "\033]6;1;bg;green;brightness;$2\a"
    echo -ne "\033]6;1;bg;blue;brightness;$3\a"
}
tab-reset() {
    echo -ne "\033]6;1;bg;*;default\a"
    trap - INT EXIT
}

# Change the color of the tab when using SSH
# reset the color after the connection closes
color-ssh() {
    if [[ -n "$ITERM_SESSION_ID" ]]; then
        trap "tab-reset" INT EXIT
        if [[ "$*" =~ "production|ec2-.*compute-1" ]]; then
            tab-color 255 0 0
        else
            tab-color 144 181 80 #0 255 0
        fi
    fi
    ssh $*
}
compdef _ssh color-ssh=ssh

alias ssh=color-ssh

However, today I have discovered that the autocomplete is now broken! My ssh no longer autocompletes if I run this script. How do I diagnose what is going on?

Edit: Disabling oh-my-zsh and sourcing the file leads to the error: command not found: compdef.

Answer 1

Ok, I've found the solution: deleting all zcompdump files solved the problem:

rm ~/.zcompdump*

Answer 2

I ran the following and it fix the tab completion.

autoload -U compinit && compinit
autoload -U bashcompinit && bashcompinit