fix(installer): fix error message if $ZSH exists when installing

Also prefix all formatting functions with fmt_

Related: #9427

.editorconfig

@@ -4,7 +4,5 @@ root = true
 end_of_line = lf
 insert_final_newline = true
 charset = utf-8
-
-[*.sh]
-indent_size = 4
-indent_style = tab
+indent_size = 2
+indent_style = space

tools/install.sh

@@ -37,6 +37,9 @@
 #
 set -e
 
+# Track if $ZSH was provided
+custom_zsh=${ZSH:+yes}
+
 # Default settings
 ZSH=${ZSH:-~/.oh-my-zsh}
 REPO=${REPO:-ohmyzsh/ohmyzsh}
@@ -53,14 +56,18 @@ command_exists() {
 	command -v "$@" >/dev/null 2>&1
 }
 
-error() {
+fmt_error() {
   echo ${RED}"Error: $@"${RESET} >&2
 }
 
-underline() {
+fmt_underline() {
   echo "$(printf '\033[4m')$@$(printf '\033[24m')"
 }
 
+fmt_code() {
+  echo "\`$(printf '\033[38;5;247m')$@${RESET}\`"
+}
+
 setup_color() {
 	# Only use colors if connected to a terminal
 	if [ -t 1 ]; then
@@ -91,13 +98,13 @@ setup_ohmyzsh() {
   echo "${BLUE}Cloning Oh My Zsh...${RESET}"
 
   command_exists git || {
-		error "git is not installed"
+    fmt_error "git is not installed"
     exit 1
   }
 
   if [ "$OSTYPE" = cygwin ] && git --version | grep -q msysgit; then
-		error "Windows/MSYS Git is not supported on Cygwin"
-		error "Make sure the Cygwin git package is installed and is first on the \$PATH"
+    fmt_error "Windows/MSYS Git is not supported on Cygwin"
+    fmt_error "Make sure the Cygwin git package is installed and is first on the \$PATH"
     exit 1
   fi
 
@@ -106,7 +113,7 @@ setup_ohmyzsh() {
     -c fetch.fsck.zeroPaddedFilemode=ignore \
     -c receive.fsck.zeroPaddedFilemode=ignore \
     --depth=1 --branch "$BRANCH" "$REMOTE" "$ZSH" || {
-		error "git clone of oh-my-zsh repo failed"
+    fmt_error "git clone of oh-my-zsh repo failed"
     exit 1
   }
 
@@ -130,8 +137,8 @@ setup_zshrc() {
     if [ -e "$OLD_ZSHRC" ]; then
       OLD_OLD_ZSHRC="${OLD_ZSHRC}-$(date +%Y-%m-%d_%H-%M-%S)"
       if [ -e "$OLD_OLD_ZSHRC" ]; then
-				error "$OLD_OLD_ZSHRC exists. Can't back up ${OLD_ZSHRC}"
-				error "re-run the installer again in a couple of seconds"
+        fmt_error "$OLD_OLD_ZSHRC exists. Can't back up ${OLD_ZSHRC}"
+        fmt_error "re-run the installer again in a couple of seconds"
         exit 1
       fi
       mv "$OLD_ZSHRC" "${OLD_OLD_ZSHRC}"
@@ -160,16 +167,16 @@ setup_shell() {
   fi
 
   # If this user's login shell is already "zsh", do not attempt to switch.
-	if [ "$(basename "$SHELL")" = "zsh" ]; then
+  if [ "$(basename -- "$SHELL")" = "zsh" ]; then
     return
   fi
 
   # If this platform doesn't provide a "chsh" command, bail out.
   if ! command_exists chsh; then
-		cat <<-EOF
-			I can't change your shell automatically because this system does not have chsh.
-			${BLUE}Please manually change your default shell to zsh${RESET}
-		EOF
+    cat <<EOF
+I can't change your shell automatically because this system does not have chsh.
+${BLUE}Please manually change your default shell to zsh${RESET}
+EOF
     return
   fi
 
@@ -197,7 +204,7 @@ setup_shell() {
     elif [ -f /usr/share/defaults/etc/shells ]; then # Solus OS
       shells_file=/usr/share/defaults/etc/shells
     else
-			error "could not find /etc/shells file. Change your default shell manually."
+      fmt_error "could not find /etc/shells file. Change your default shell manually."
       return
     fi
 
@@ -206,8 +213,8 @@ setup_shell() {
     # 2. If that fails, get a zsh path from the shells file, then check it actually exists
     if ! zsh=$(which zsh) || ! grep -qx "$zsh" "$shells_file"; then
       if ! zsh=$(grep '^/.*/zsh$' "$shells_file" | tail -1) || [ ! -f "$zsh" ]; then
-				error "no zsh binary found or not present in '$shells_file'"
-				error "change your default shell manually."
+        fmt_error "no zsh binary found or not present in '$shells_file'"
+        fmt_error "change your default shell manually."
         return
       fi
     fi
@@ -222,7 +229,7 @@ setup_shell() {
 
   # Actually change the default shell to zsh
   if ! chsh -s "$zsh"; then
-		error "chsh command unsuccessful. Change your default shell manually."
+    fmt_error "chsh command unsuccessful. Change your default shell manually."
   else
     export SHELL="$zsh"
     echo "${GREEN}Shell successfully changed to '$zsh'.${RESET}"
@@ -232,7 +239,7 @@ setup_shell() {
 }
 
 main() {
-	# Run as unattended if stdin is closed
+  # Run as unattended if stdin is not a tty
   if [ ! -t 0 ]; then
     RUNZSH=no
     CHSH=no
@@ -256,10 +263,24 @@ main() {
   fi
 
   if [ -d "$ZSH" ]; then
-		cat <<-EOF
-			${YELLOW}You already have Oh My Zsh installed.${RESET}
-			You'll need to remove '$ZSH' if you want to reinstall.
-		EOF
+    echo "${YELLOW}The \$ZSH folder already exists ($ZSH).${RESET}"
+    if [ "$custom_zsh" = yes ]; then
+      cat <<EOF
+
+You ran the installer with the \$ZSH setting or the \$ZSH variable is
+exported. You have 3 options:
+
+1. Unset the ZSH variable when calling the installer:
+   $(fmt_code "ZSH= sh install.sh")
+2. Install Oh My Zsh to a directory that doesn't exist yet:
+   $(fmt_code "ZSH=path/to/new/ohmyzsh/folder sh install.sh")
+3. (Caution) If the folder doesn't contain important information,
+   you can just remove it with $(fmt_code "rm -r $ZSH")
+
+EOF
+    else
+      echo "You'll need to remove it if you want to reinstall."
+    fi
     exit 1
   fi
 
@@ -268,24 +289,24 @@ main() {
   setup_shell
 
   printf "$GREEN"
-	cat <<-'EOF'
+  cat <<'EOF'
          __                                     __
   ____  / /_     ____ ___  __  __   ____  _____/ /_
  / __ \/ __ \   / __ `__ \/ / / /  /_  / / ___/ __ \
-		/ /_/ / / / /  / / / / / / /_/ /    / /_(__  ) / / /
-		\____/_/ /_/  /_/ /_/ /_/\__, /    /___/____/_/ /_/
+/ /_/ / / / /  / / / / / / /_/ /    / /_(__  ) / / /
+\____/_/ /_/  /_/ /_/ /_/\__, /    /___/____/_/ /_/
                         /____/                       ....is now installed!
 
 
-	EOF
-	cat <<-EOF
-		Before you scream Oh My Zsh! please look over the ~/.zshrc file to select plugins, themes, and options.
+EOF
+  cat <<EOF
+Before you scream Oh My Zsh! please look over the ~/.zshrc file to select plugins, themes, and options.
 
-		• Follow us on Twitter: $(underline https://twitter.com/ohmyzsh)
-		• Join our Discord server: $(underline https://discord.gg/ohmyzsh)
-		• Get stickers, shirts, coffee mugs and other swag: $(underline https://shop.planetargon.com/collections/oh-my-zsh)
+• Follow us on Twitter: $(fmt_underline https://twitter.com/ohmyzsh)
+• Join our Discord server: $(fmt_underline https://discord.gg/ohmyzsh)
+• Get stickers, shirts, coffee mugs and other swag: $(fmt_underline https://shop.planetargon.com/collections/oh-my-zsh)
 
-	EOF
+EOF
   printf "$RESET"
 
   if [ $RUNZSH = no ]; then