Add completion for BSD chflags(1) command

completions/Makefile.am

@@ -51,6 +51,7 @@ bashcomp_DATA = 2to3 \
 		check_db \
 		check_perms \
 		checksec \
+		chflags \
 		_chfn \
 		chgrp \
 		chkconfig \

completions/chflags

@@ -0,0 +1,52 @@
+# chflags(1) completion                                      -*- shell-script -*-
+
+[[ $OSTYPE == *@(bsd|darwin)* ]] || return 1
+
+# References
+#
+# [1] FreeBSD - https://man.freebsd.org/cgi/man.cgi?chflags(1)
+# [2] NetBSD - https://man.netbsd.org/NetBSD-9.0/chflags.1
+# [3] OpenBSD - https://man.openbsd.org/chflags.1
+
+_comp_cmd_chflags()
+{
+    local cur prev words cword comp_args
+    _comp_initialize -- "$@" || return
+
+    if [[ $cur == -* ]]; then
+        # Complete -options
+        local w opts=""
+        for w in "${words[@]}"; do
+            [[ $w == -R ]] && opts="-H -L -P" && break
+        done
+        [[ $OSTYPE == *freebsd* ]] && opts="$opts -x"
+        _comp_compgen -- -W '-f -h -v -R $opts'
+    else
+        local REPLY
+        # The first argument is a list of flags; the rest are filedir.
+        _comp_count_args
+        if ((REPLY == 1)); then
+            case "$OSTYPE" in
+                *netbsd*)
+                    _comp_delimited , -W '
+                        arch opaque nodump sappnd schg uappnd uchg'
+                    ;;
+                *openbsd*)
+                    _comp_delimited , -W 'arch nodump sappnd schg uappnd uchg'
+                    ;;
+                *)
+                    _comp_delimited , -W '
+                        simmutable nosimmutable sappend nosappend archived
+                        noarchived sunlink nosunlink opaque noopaque nodump
+                        dump uimmutable nouimmutable uappend nouappend hidden
+                        nohidden uunlink nouunlink'
+                    ;;
+            esac
+        else
+            _comp_compgen_filedir
+        fi
+    fi
+} &&
+    complete -F _comp_cmd_chflags chflags
+
+# ex: filetype=sh

test/t/Makefile.am

@@ -73,6 +73,7 @@ EXTRA_DIST = \
 	test_check_db.py \
 	test_check_perms.py \
 	test_checksec.py \
+	test_chflags.py \
 	test_chfn.py \
 	test_chgrp.py \
 	test_chkconfig.py \

test/t/test_chflags.py

@@ -0,0 +1,19 @@
+import pytest
+
+
+class TestChflags:
+    @pytest.mark.complete("chflags no")
+    def test_basic(self, completion):
+        assert completion
+
+    @pytest.mark.complete("chflags -")
+    def test_options(self, completion):
+        assert completion and "-P" not in completion
+
+    @pytest.mark.complete("chflags -R -")
+    def test_options_after_R(self, completion):
+        assert "-P" in completion
+
+    @pytest.mark.complete("chflags -v sappend ")
+    def test_first_word(self, completion):
+        assert completion