Review feedback

1. `unset` -> `unset -v`
2. Forced a dynamic unset by calling unset from a child scope. Added a
   test.

Author: Seamus Connor

bash_completion

@@ -149,6 +149,22 @@ dequote()
     eval printf %s "$1" 2>/dev/null
 }
 
+# Unset the given variables across a scope boundary. Useful for unshadowing
+# global scoped variables. Note that simply calling unset on a local variable
+# will not unshadow the global variable. Rather, the result will be a local
+# variable in an unset state.
+# Usage: local IFS=$'|'; _comp_unlocal IFS
+# Param: $* Variable names to be unset
+_comp_unlocal()
+{
+    local reset=$([[ ${BASH_VERSINFO[0]} -eq 5 ]] && {
+                      shopt -p localvar_unset
+                      shopt -u localvar_unset
+                  })
+    unset -v "$@"
+    $reset
+}
+
 # Assign variable one scope above the caller
 # Usage: local "$1" && _upvar $1 "value(s)"
 # Param: $1  Variable name to assign value to
@@ -726,7 +742,7 @@ _comp_delimited()
         # Do not remove the last from existing if it's not followed by the
         # delimiter so we get space appended.
         [[ ! $cur || $cur == *"$delimiter" ]] || unset -v "existing[${#existing[@]}-1]"
-        unset IFS
+        _comp_unlocal IFS
         if ((${#COMPREPLY[@]})); then
             for x in ${existing+"${existing[@]}"}; do
                 for i in "${!COMPREPLY[@]}"; do
@@ -1259,7 +1275,7 @@ else
             local -a psout=($({
                 command ps ax -o command= || command ps ax -o comm=
             } 2>/dev/null))
-            unset IFS
+            _comp_unlocal IFS
             for line in "${psout[@]}"; do
                 if ((i == -1)); then
                     # First line, see if it has COMMAND column header. For
@@ -1816,7 +1832,7 @@ _known_hosts_real()
         #          spaces in their name work (watch out for ~ expansion
         #          breakage! Alioth#311595)
         tmpkh=($(awk 'sub("^[ \t]*([Gg][Ll][Oo][Bb][Aa][Ll]|[Uu][Ss][Ee][Rr])[Kk][Nn][Oo][Ww][Nn][Hh][Oo][Ss][Tt][Ss][Ff][Ii][Ll][Ee][ \t=]+", "") { print $0 }' "${config[@]}" | sort -u))
-        unset IFS
+        _comp_unlocal IFS
     fi
     if ((${#tmpkh[@]} != 0)); then
         local j
@@ -1872,7 +1888,7 @@ _known_hosts_real()
                         # Add host to candidates
                         COMPREPLY+=($host)
                     done
-                    unset IFS
+                    _comp_unlocal IFS
                 done <"$i"
             done
             ((${#COMPREPLY[@]})) &&
@@ -2352,7 +2368,7 @@ __load_completion()
     for dir in ${XDG_DATA_DIRS:-/usr/local/share:/usr/share}; do
         dirs+=($dir/bash-completion/completions)
     done
-    unset IFS
+    _comp_unlocal IFS
 
     if [[ $BASH_SOURCE == */* ]]; then
         dirs+=("${BASH_SOURCE%/*}/completions")

completions/7z

@@ -51,7 +51,7 @@ _7z()
             compopt -o filenames
             local IFS=$'\n'
             COMPREPLY=($(compgen -d -P${cur:0:2} -S/ -- "${cur:2}"))
-            unset IFS
+            _comp_unlocal
             $reset
             compopt -o nospace
             return

completions/_umount.linux

@@ -55,15 +55,15 @@ _linux_fstab()
                 __linux_fstab_unescape fs_label
                 local IFS=$'\0'
                 COMPREPLY+=("$fs_label")
-                unset IFS
+                _comp_unlocal
             fi
         else
             __linux_fstab_unescape fs_spec
             __linux_fstab_unescape fs_file
             local IFS=$'\0'
             [[ $fs_spec == */* ]] && COMPREPLY+=("$fs_spec")
             [[ $fs_file == */* ]] && COMPREPLY+=("$fs_file")
-            unset IFS
+            _comp_unlocal
         fi
     done
 

completions/svcadm

@@ -46,7 +46,7 @@ _smf_complete_fmri()
             # number of components
             local IFS="/"
             set -- $fmri
-            unset IFS
+            _comp_unlocal
             case $# in
                 1) fmri_part_list=" $1" ;;
                 2) fmri_part_list=" $2 $1/$2" ;;

test/t/test_bash.py

@@ -1,7 +1,24 @@
 import pytest
+import sys
 
+from conftest import assert_bash_exec
 
 class TestBash:
     @pytest.mark.complete("bash --", require_cmd=True)
     def test_1(self, completion):
         assert completion
+
+    def test_comp_unlocal(self, bash):
+        # bash.logfile = sys.stderr
+        cmd = ( 'foo() { '
+                      'local VAR=inner; '
+                      '_comp_unlocal VAR; '
+                      'echo $VAR; '
+                '}; '
+                'VAR=outer; foo; unset VAR foo; '
+        )
+        res = assert_bash_exec(bash, cmd, want_output=True).strip()
+        assert res == "outer"
+
+        # assert_bash_exec(bash, '[[ $(shopt -p localvar_unset || true) != "shopt -u localvar_unset"]]')
+        # assert_bash_exec(bash, 'shopt -u localvar_unset || true')