Make friendly to set -u

lib/completion.zsh

@@ -53,7 +53,7 @@ zstyle ':completion:*:*:*:users' ignored-patterns \
 # ... unless we really want to.
 zstyle '*' single-ignored show
 
-if [ "x$COMPLETION_WAITING_DOTS" = "xtrue" ]; then
+if [ "x${COMPLETION_WAITING_DOTS:-}" = "xtrue" ]; then
   expand-or-complete-with-dots() {
     echo -n "\e[31m......\e[0m"
     zle expand-or-complete

lib/correction.zsh

@@ -1,4 +1,4 @@
-if [[ "$ENABLE_CORRECTION" == "true" ]]; then
+if [[ "${ENABLE_CORRECTION:-}" == "true" ]]; then
   alias ebuild='nocorrect ebuild'
   alias gist='nocorrect gist'
   alias heroku='nocorrect heroku'

lib/git.zsh

@@ -17,7 +17,7 @@ parse_git_dirty() {
     if [[ $POST_1_7_2_GIT -gt 0 ]]; then
       FLAGS+='--ignore-submodules=dirty'
     fi
-    if [[ "$DISABLE_UNTRACKED_FILES_DIRTY" == "true" ]]; then
+    if [[ "${DISABLE_UNTRACKED_FILES_DIRTY:-}" == "true" ]]; then
       FLAGS+='--untracked-files=no'
     fi
     STATUS=$(command git status ${FLAGS} 2> /dev/null | tail -n1)

lib/history.zsh

@@ -1,5 +1,5 @@
 ## Command history configuration
-if [ -z "$HISTFILE" ]; then
+if [ -z "${HISTFILE:-}" ]; then
     HISTFILE=$HOME/.zsh_history
 fi
 
@@ -7,7 +7,7 @@ HISTSIZE=10000
 SAVEHIST=10000
 
 # Show history
-case $HIST_STAMPS in
+case ${HIST_STAMPS:-} in
   "mm/dd/yyyy") alias history='fc -fl 1' ;;
   "dd.mm.yyyy") alias history='fc -El 1' ;;
   "yyyy-mm-dd") alias history='fc -il 1' ;;

lib/misc.zsh

@@ -17,6 +17,6 @@ alias please='sudo'
 alias afind='ack-grep -il'
 
 # only define LC_CTYPE if undefined
-if [[ -z "$LC_CTYPE" && -z "$LC_ALL" ]]; then
+if [[ -z "${LC_CTYPE:-}" && -z "${LC_ALL:-}" ]]; then
 	export LC_CTYPE=${LANG%%:*} # pick the first entry from LANG
 fi

lib/termsupport.zsh

@@ -7,7 +7,7 @@
 # (In screen, only short_tab_title is used)
 # Limited support for Apple Terminal (Terminal can't set window and tab separately)
 function title {
-  [[ "$EMACS" == *term* ]] && return
+  [[ "${EMACS:-}" == *term* ]] && return
 
   # if $2 is unset use $1 as default
   # if it is set and empty, leave it as is
@@ -15,7 +15,7 @@ function title {
 
   if [[ "$TERM" == screen* ]]; then
     print -Pn "\ek$1:q\e\\" #set screen hardstatus, usually truncated at 20 chars
-  elif [[ "$TERM" == xterm* ]] || [[ "$TERM" == rxvt* ]] || [[ "$TERM" == ansi ]] || [[ "$TERM_PROGRAM" == "iTerm.app" ]]; then
+  elif [[ "$TERM" == xterm* ]] || [[ "$TERM" == rxvt* ]] || [[ "$TERM" == ansi ]] || [[ "${TERM_PROGRAM:-}" == "iTerm.app" ]]; then
     print -Pn "\e]2;$2:q\a" #set window name
     print -Pn "\e]1;$1:q\a" #set icon (=tab) name
   fi
@@ -26,7 +26,7 @@ ZSH_THEME_TERM_TITLE_IDLE="%n@%m: %~"
 
 # Runs before showing the prompt
 function omz_termsupport_precmd {
-  if [[ $DISABLE_AUTO_TITLE == true ]]; then
+  if [[ ${DISABLE_AUTO_TITLE:-} == true ]]; then
     return
   fi
 
@@ -35,7 +35,7 @@ function omz_termsupport_precmd {
 
 # Runs before executing the command
 function omz_termsupport_preexec {
-  if [[ $DISABLE_AUTO_TITLE == true ]]; then
+  if [[ ${DISABLE_AUTO_TITLE:-} == true ]]; then
     return
   fi
 
@@ -57,7 +57,7 @@ preexec_functions+=(omz_termsupport_preexec)
 function omz_termsupport_cwd {
   # Notify Terminal.app of current directory using undocumented OSC sequence
   # found in OS X 10.9 and 10.10's /etc/bashrc
-  if [[ $TERM_PROGRAM == Apple_Terminal ]] && [[ -z $INSIDE_EMACS ]]; then
+  if [[ ${TERM_PROGRAM:-} == Apple_Terminal ]] && [[ -z $INSIDE_EMACS ]]; then
     local PWD_URL="file://$HOSTNAME${PWD// /%20}"
     printf '\e]7;%s\a' "$PWD_URL"
   fi

lib/theme-and-appearance.zsh

@@ -3,7 +3,7 @@ autoload -U colors && colors
 export LSCOLORS="Gxfxcxdxbxegedabagacad"
 
 # Enable ls colors
-if [ "$DISABLE_LS_COLORS" != "true" ]
+if [ "${DISABLE_LS_COLORS:-}" != "true" ]
 then
   # Find the option for using colors in ls, depending on the version: Linux or BSD
   if [[ "$(uname -s)" == "NetBSD" ]]; then
@@ -24,7 +24,7 @@ setopt auto_cd
 setopt multios
 setopt cdablevars
 
-if [[ x$WINDOW != x ]]
+if [[ x${WINDOW:-} != x ]]
 then
     SCREEN_NO="%B$WINDOW%b "
 else