Fail if options are passed incorrectly

The previous commit tried to fix up incorrectly passed options, but that
didn't always work.  Instead, try to detect known bad options (on a
best-effort basis) and print an error message.

Author: DemiMarie

dom0-updates/qubes-dom0-update

@@ -1,7 +1,7 @@
 #!/bin/bash --
 set -euo pipefail
 shopt -s assoc_expand_once
-unset YUM_ACTION UPDATEVM shift_amount
+unset YUM_ACTION UPDATEVM
 
 check_template_in_args () {
     local pkg
@@ -91,25 +91,24 @@ options_with_args=(
     [--setopt]=
 )
 
-option_takes_arg () {
-    [[ "$1" =~ ^-[^dexR]*[dexR]$ ]] || [[ -v options_with_args["$1"] ]]
-}
-
 # Filter out some dnf options and collect packages list
 while [ $# -gt 0 ]; do
-    shift_amount=1
-    if option_takes_arg "$1"; then
+    if [[ -v options_with_args["$1"] ]]; then
         if [[ "$#" -lt 2 ]]; then
-            printf 'Missing argument to %s\n' "$1" >&2
-            exit 1
-        fi
-        shift_amount=2
+            printf 'Missing argument to %s\n' "$1"
+        else
+            printf '%s %q must be passed as %s=%q\n' "$1" "$2" "$1" "$2"
+        fi >&2
+        exit 1
+    elif [[ "$1" =~ ^-[^dexR]*[dexR]$ ]]; then
+        if [[ "$#" -lt 2 ]]; then
+            printf 'Missing argument to %q\n' "$1"
+        else
+            printf '%q %q must be written as %q%q\n' "$1" "$2" "$1" "$2"
+        fi >&2
+        exit 1
     fi
     case "$1" in
-        --enablerepo|--disablerepo)
-            UPDATEVM_OPTS+=("$1=$2")
-            QVMTEMPLATE_OPTS+=("$1=$2")
-            ;;
         --enablerepo=*|\
         --disablerepo=*)
             UPDATEVM_OPTS+=( "$1" )
@@ -142,10 +141,6 @@ while [ $# -gt 0 ]; do
         --force-xen-upgrade)
             FORCE_XEN_UPGRADE=1
             ;;
-        --action=)
-            YUM_ACTION=$1
-            UPDATEVM_OPTS+=( "$1=$2" )
-            ;;
         --action=*)
             YUM_ACTION=${1#--action=}
             UPDATEVM_OPTS+=( "$1" )
@@ -159,17 +154,17 @@ while [ $# -gt 0 ]; do
             fi
             ;;
         -*)
-            YUM_OPTS+=( "${@:1:shift_amount}" )
-            UPDATEVM_OPTS+=( "${@:1:shift_amount}" )
-            QVMTEMPLATE_OPTS+=( "${@:1:shift_amount}" )
+            YUM_OPTS+=( "$1" )
+            UPDATEVM_OPTS+=( "$1" )
+            QVMTEMPLATE_OPTS+=( "$1" )
             ;;
         *)
             PKGS+=( "${1}" )
             UPDATEVM_OPTS+=( "$1" )
             : "${YUM_ACTION=install}"
             ;;
     esac
-    shift "$shift_amount"
+    shift
 done
 
 if [[ "$GUI" = 1 ]]; then