diff --git a/bash_completion b/bash_completion
index d36fbb7d7c1..18d0404d1ef 100644
--- a/bash_completion
+++ b/bash_completion
@@ -61,6 +61,36 @@ _comp_deprecate_func()
     eval -- "$2() { $3 \"\$@\"; }"
 }
 
+# Declare a compatibility variable name.
+# For bash 4.3+, a real name alias is created, allowing value changes to
+# "apply through" when the variables are set later. For bash versions earlier
+# than that, the operation is once-only; the value of the new variable
+# (if it's unset) is set to that of the old (if set) at call time.
+#
+# @param $1 Version of bash-completion where the deprecation occurred
+# @param $2 Old variable name
+# @param $3 New variable name
+# @since 2.12
+_comp_deprecate_var()
+{
+    if (($# != 3)); then
+        printf 'bash_completion: %s: usage: %s DEPRECATION_VERSION OLD_NAME NEW_NAME\n' "$FUNCNAME" "$FUNCNAME"
+        return 2
+    fi
+    if [[ $2 != [a-zA-Z_]*([a-zA-Z_0-9]) ]]; then
+        printf 'bash_completion: %s: %s\n' "$FUNCNAME" "\$2: invalid variable name '$1'" >&2
+        return 2
+    elif [[ $3 != [a-zA-Z_]*([a-zA-Z_0-9]) ]]; then
+        printf 'bash_completion: %s: %s\n' "$FUNCNAME" "\$3: invalid variable name '$2'" >&2
+        return 2
+    fi
+    if ((BASH_VERSINFO[0] >= 5 || BASH_VERSINFO[0] == 4 && BASH_VERSINFO[1] >= 3)); then
+        eval "declare -gn $2=$3"
+    elif [[ -v $2 && ! -v $3 ]]; then
+        printf -v "$3" %s "$2"
+    fi
+}
+
 # A lot of the following one-liners were taken directly from the
 # completion examples provided with the bash 2.04 source distribution
 
@@ -1092,14 +1122,13 @@ _comp_compgen_filedir()
         # the fallback condition with the "plus" dirs.
         local _opts=(-f -X "$_xspec")
         [[ $_xspec ]] && _plusdirs=(-o plusdirs)
-        [[ ${BASH_COMPLETION_FILEDIR_FALLBACK-${COMP_FILEDIR_FALLBACK-}} ||
-            ! ${_plusdirs-} ]] ||
+        [[ ${BASH_COMPLETION_FILEDIR_FALLBACK-} || ! ${_plusdirs-} ]] ||
             _opts+=("${_plusdirs[@]}")
 
         _comp_compgen -v toks -c "$_quoted" -- "${_opts[@]}"
 
         # Try without filter if it failed to produce anything and configured to
-        [[ ${BASH_COMPLETION_FILEDIR_FALLBACK-${COMP_FILEDIR_FALLBACK-}} &&
+        [[ ${BASH_COMPLETION_FILEDIR_FALLBACK-} &&
             $_arg && ${#toks[@]} -lt 1 ]] &&
             _comp_compgen -av toks -c "$_quoted" -- \
                 -f ${_plusdirs+"${_plusdirs[@]}"}
@@ -2626,7 +2655,7 @@ _comp_compgen_known_hosts__impl()
     fi
 
     # Add hosts reported by avahi-browse, if desired and it's available.
-    if [[ ${BASH_COMPLETION_KNOWN_HOSTS_WITH_AVAHI-${COMP_KNOWN_HOSTS_WITH_AVAHI-}} ]] &&
+    if [[ ${BASH_COMPLETION_KNOWN_HOSTS_WITH_AVAHI-} ]] &&
         type avahi-browse &>/dev/null; then
         # Some old versions of avahi-browse reportedly didn't have -k
         # (even if mentioned in the manpage); those we do not support any more.
@@ -2644,7 +2673,7 @@ _comp_compgen_known_hosts__impl()
 
     # Add results of normal hostname completion, unless
     # `BASH_COMPLETION_KNOWN_HOSTS_WITH_HOSTFILE' is set to an empty value.
-    if [[ ${BASH_COMPLETION_KNOWN_HOSTS_WITH_HOSTFILE-${COMP_KNOWN_HOSTS_WITH_HOSTFILE-1}} ]]; then
+    if [[ ${BASH_COMPLETION_KNOWN_HOSTS_WITH_HOSTFILE-set} ]]; then
         _comp_compgen -av known_hosts -- -A hostname -P "$prefix" -S "$suffix"
     fi
 
@@ -3006,8 +3035,7 @@ _comp_compgen_filedir_xspec()
     _comp_compgen -av toks -c "$quoted" -- -f -X "@(|!($xspec))"
 
     # Try without filter if it failed to produce anything and configured to
-    [[ ${BASH_COMPLETION_FILEDIR_FALLBACK-${COMP_FILEDIR_FALLBACK-}} &&
-        ${#toks[@]} -lt 1 ]] &&
+    [[ ${BASH_COMPLETION_FILEDIR_FALLBACK-} && ${#toks[@]} -lt 1 ]] &&
         _comp_compgen -av toks -c "$quoted" -- -f
 
     ((${#toks[@]})) || return 1
diff --git a/bash_completion.d/000_bash_completion_compat.bash b/bash_completion.d/000_bash_completion_compat.bash
index 6971fa9651e..480ffcc6a75 100644
--- a/bash_completion.d/000_bash_completion_compat.bash
+++ b/bash_completion.d/000_bash_completion_compat.bash
@@ -42,6 +42,10 @@ _comp_deprecate_func 2.12 _longopt _comp_complete_longopt
 _comp_deprecate_func 2.12 _filedir_xspec _comp_complete_filedir_xspec
 _comp_deprecate_func 2.12 _minimal _comp_complete_minimal
 
+_comp_deprecate_var 2.12 COMP_FILEDIR_FALLBACK BASH_COMPLETION_FILEDIR_FALLBACK
+_comp_deprecate_var 2.12 COMP_KNOWN_HOSTS_WITH_AVAHI BASH_COMPLETION_KNOWN_HOSTS_WITH_AVAHI
+_comp_deprecate_var 2.12 COMP_KNOWN_HOSTS_WITH_HOSTFILE BASH_COMPLETION_KNOWN_HOSTS_WITH_HOSTFILE
+
 # @deprecated 2.12 Use `_comp_xspecs`
 declare -Ag _xspecs
 
diff --git a/completions/configure b/completions/configure
index 6d74b112862..a61a05dc382 100644
--- a/completions/configure
+++ b/completions/configure
@@ -1,5 +1,8 @@
 # bash completion for configure                            -*- shell-script -*-
 
+_comp_deprecate_var 2.12 \
+    COMP_CONFIGURE_HINTS BASH_COMPLETION_CMD_CONFIGURE_HINTS
+
 _comp_cmd_configure()
 {
     local cur prev words cword was_split comp_args
@@ -27,7 +30,7 @@ _comp_cmd_configure()
 
     # if $BASH_COMPLETION_CMD_CONFIGURE_HINTS is not null, then completions of
     # the form --option=SETTING will include 'SETTING' as a contextual hint
-    if [[ ${BASH_COMPLETION_CMD_CONFIGURE_HINTS-${COMP_CONFIGURE_HINTS-}} ]]; then
+    if [[ ${BASH_COMPLETION_CMD_CONFIGURE_HINTS-} ]]; then
         _comp_compgen_split -- "$("$1" --help 2>&1 |
             _comp_awk '/^  --[A-Za-z]/ { print $1; \
             if ($2 ~ /--[A-Za-z]/) print $2 }' | command sed -e 's/[[,].*//g')"
diff --git a/completions/cvs b/completions/cvs
index 50b9f2b83ed..b8398af3f1d 100644
--- a/completions/cvs
+++ b/completions/cvs
@@ -1,5 +1,8 @@
 # cvs(1) completion                                        -*- shell-script -*-
 
+_comp_deprecate_var 2.12 \
+    COMP_CVS_REMOTE BASH_COMPLETION_CMD_CVS_REMOTE
+
 _comp_cmd_cvs__entries()
 {
     local prefix=${cur%/*}/ IFS=$'\n'
@@ -256,7 +259,7 @@ _comp_cmd_cvs()
                 # if $BASH_COMPLETION_CMD_CVS_REMOTE is not null, 'cvs commit'
                 # will complete on remotely checked-out files (requires
                 # passwordless access to the remote repository
-                if [[ ${BASH_COMPLETION_CMD_CVS_REMOTE-${COMP_CVS_REMOTE-}} ]]; then
+                if [[ ${BASH_COMPLETION_CMD_CVS_REMOTE-} ]]; then
                     # this is the least computationally intensive way found so
                     # far, but other changes (something other than
                     # changed/removed/new) may be missing
diff --git a/completions/iwconfig b/completions/iwconfig
index dc5962fcce7..7fbc985b61c 100644
--- a/completions/iwconfig
+++ b/completions/iwconfig
@@ -1,5 +1,8 @@
 # iwconfig completion                                      -*- shell-script -*-
 
+_comp_deprecate_var 2.12 \
+    COMP_IWLIST_SCAN BASH_COMPLETION_CMD_IWCONFIG_SCAN
+
 _comp_cmd_iwconfig()
 {
     local cur prev words cword comp_args
@@ -13,7 +16,7 @@ _comp_cmd_iwconfig()
             ;;
         essid)
             _comp_compgen -- -W 'on off any'
-            if [[ ${BASH_COMPLETION_CMD_IWCONFIG_SCAN-${COMP_IWLIST_SCAN-}} ]]; then
+            if [[ ${BASH_COMPLETION_CMD_IWCONFIG_SCAN-} ]]; then
                 _comp_compgen -a split -- "$(iwlist "${words[1]}" scan |
                     _comp_awk -F '\"' '/ESSID/ {print $2}')"
             fi
@@ -36,7 +39,7 @@ _comp_cmd_iwconfig()
             ;;
         ap)
             _comp_compgen -- -W 'on off any'
-            if [[ ${BASH_COMPLETION_CMD_IWCONFIG_SCAN-${COMP_IWLIST_SCAN-}} ]]; then
+            if [[ ${BASH_COMPLETION_CMD_IWCONFIG_SCAN-} ]]; then
                 _comp_compgen -a split -- "$(iwlist "${words[1]}" scan |
                     _comp_awk -F ': ' '/Address/ {print $2}')"
             fi
diff --git a/completions/tar b/completions/tar
index d4fa32fb0de..83a40735dfa 100644
--- a/completions/tar
+++ b/completions/tar
@@ -56,6 +56,9 @@
 # `$BASH_COMPLETION_CMD_TAR_INTERNAL_PATHS` environment variable to a non-null
 # value *before sourcing* this completion toggles that the other way around.
 
+_comp_deprecate_var 2.12 \
+    COMP_TAR_INTERNAL_PATHS BASH_COMPLETION_CMD_TAR_INTERNAL_PATHS
+
 _comp_cmd_gtar__parse_help_opt()
 {
     local opttype arg opt separator optvar
@@ -723,7 +726,7 @@ _comp_cmd_tar()
     $func "$@"
 
     # Install real completion for subsequent completions
-    if [[ ${BASH_COMPLETION_CMD_TAR_INTERNAL_PATHS-${COMP_TAR_INTERNAL_PATHS-}} ]]; then
+    if [[ ${BASH_COMPLETION_CMD_TAR_INTERNAL_PATHS-} ]]; then
         complete -F $func -o dirnames tar
     else
         complete -F $func tar
@@ -731,7 +734,7 @@ _comp_cmd_tar()
     unset -f "$FUNCNAME"
 }
 
-if [[ ${BASH_COMPLETION_CMD_TAR_INTERNAL_PATHS-${COMP_TAR_INTERNAL_PATHS-}} ]]; then
+if [[ ${BASH_COMPLETION_CMD_TAR_INTERNAL_PATHS-} ]]; then
     complete -F _comp_cmd_tar -o dirnames tar
     complete -F _comp_cmd_tar__gnu -o dirnames gtar
     complete -F _comp_cmd_tar__posix -o dirnames bsdtar
diff --git a/test/t/test_cvsps.py b/test/t/test_cvsps.py
index 4039893c853..209583255f1 100644
--- a/test/t/test_cvsps.py
+++ b/test/t/test_cvsps.py
@@ -1,7 +1,10 @@
 import pytest
 
 
-@pytest.mark.bashcomp(pre_cmds=("HOME=$PWD/cvs",))
+@pytest.mark.bashcomp(
+    pre_cmds=("HOME=$PWD/cvs",),
+    ignore_env=r"^[+-]COMP_CVS_REMOTE=",
+)
 class TestCvsps:
     @pytest.mark.complete("cvsps -", require_cmd=True)
     def test_1(self, completion):