diff --git a/builtin/completion_osh.py b/builtin/completion_osh.py
index 8dc8a8e7e..65125e904 100644
--- a/builtin/completion_osh.py
+++ b/builtin/completion_osh.py
@@ -5,6 +5,7 @@
 from _devbuild.gen.syntax_asdl import loc
 from _devbuild.gen.value_asdl import (value, value_e)
 
+from core import bash_impl
 from core import completion
 from core import error
 from core import state
@@ -454,9 +455,13 @@ def Run(self, cmd_val):
         # TODO: How does the user test a completion function programmatically?  Set
         # COMP_ARGV?
         val = self.mem.GetValue('COMP_ARGV')
-        if val.tag() != value_e.BashArray:
+        if val.tag() == value_e.BashArray:
+            comp_argv = cast(value.BashArray, val).strs
+        elif val.tag() == value_e.SparseArray:
+            comp_argv = bash_impl.SparseArray_GetValues(
+                cast(value.SparseArray, val))
+        else:
             raise error.Usage("COMP_ARGV should be an array", loc.Missing)
-        comp_argv = cast(value.BashArray, val).strs
 
         # These are the ones from COMP_WORDBREAKS that we care about.  The rest occur
         # "outside" of words.
diff --git a/core/completion.py b/core/completion.py
index 4601712a6..2789c99cf 100755
--- a/core/completion.py
+++ b/core/completion.py
@@ -627,21 +627,23 @@ def Matches(self, comp):
                 # unset it.  Not changing it means there were no completions.
                 # TODO: This writes over the command line; it would be better
                 # to use an error object.
-                print_stderr('osh error: Ran function %r but COMPREPLY was unset' %
-                             self.func.name)
+                print_stderr(
+                    'osh error: Ran function %r but COMPREPLY was unset' %
+                    self.func.name)
                 return
-
             elif case(value_e.Str):
                 val = cast(value.Str, UP_val)
                 strs = [val.s]
-
             elif case(value_e.BashArray):
                 val = cast(value.BashArray, UP_val)
                 strs = bash_impl.BashArray_GetValues(val)
-
+            elif case(value_e.SparseArray):
+                val = cast(value.SparseArray, UP_val)
+                strs = bash_impl.SparseArray_GetValues(val)
             else:
-                print_stderr('osh error: COMPREPLY should be an array or a string, got %s' %
-                             ui.ValType(val))
+                print_stderr(
+                    'osh error: COMPREPLY should be an array or a string, got %s'
+                    % ui.ValType(val))
                 return
 
         if 0:
diff --git a/spec/ble-idioms.test.sh b/spec/ble-idioms.test.sh
index 95bae8767..fc14f0eac 100644
--- a/spec/ble-idioms.test.sh
+++ b/spec/ble-idioms.test.sh
@@ -1064,6 +1064,55 @@ echo "[${a[@]: -4}][${a[*]: -4}]"
 ## END
 
 
+#### SparseArray: compgen -F _set_COMPREPLY
+case $SH in zsh|mksh|ash) exit ;; esac
+
+a=({0..9})
+unset -v 'a[2]' 'a[4]' 'a[6]'
+
+case ${SH##*/} in
+osh)
+  eval '_set_COMPREPLY() { setglobal COMPREPLY = _a2sp(a); }'
+  ;;
+*)
+  _set_COMPREPLY() { COMPREPLY=("${a[@]}"); }
+  ;;
+esac
+
+compgen -F _set_COMPREPLY
+
+## STDOUT:
+0
+1
+3
+5
+7
+8
+9
+## END
+
+## N-I zsh/mksh/ash STDOUT:
+## END
+
+
+#### SparseArray: compgen -F _set_COMPREPLY
+case $SH in bash|zsh|mksh|ash) exit ;; esac
+
+a=(echo 'Hello,' 'Bash' 'world!')
+var COMP_ARGV = _a2sp(a)
+compadjust cur prev words cword
+argv.py "$cur" "$prev" "$cword"
+argv.py "${words[@]}"
+
+## STDOUT:
+['world!', 'Bash', '3']
+['echo', 'Hello,', 'Bash', 'world!']
+## END
+
+## N-I bash/zsh/mksh/ash STDOUT:
+## END
+
+
 #### SparseArray (YSH): $[a1 === a2]
 case $SH in bash|zsh|mksh|ash) exit ;; esac