fix(rsync): Try getting rsync arguments BSD style

There is a BSD licensed version of rsync at
https://github.com/kristapsdz/openrsync, and its what comes with macOS

Author: yedayak

completions/rsync

@@ -85,11 +85,15 @@ _comp_cmd_rsync()
             # meaning before v3.2.0) contain the following unusual line in
             # --help:
             # "(-h) --help                  show this help (-h is --help only if used alone)"
-            _comp_compgen -Rv tmp help - <<<"$("$1" --help 2>&1 | command sed -e 's/^([^)]*)//')"
+            if _comp_compgen -Rv tmp help - <<<"$("$1" --help 2>&1 | command sed -e 's/^([^)]*)//')"; then
 
-            _comp_compgen -- -W '"${tmp[@]}"
-                --daemon --old-d{,irs}
-                --no-{blocking-io,detach,whole-file,inc-recursive,i-r}' -X '--no-OPTION'
+                _comp_compgen -- -W '"${tmp[@]}"
+                    --daemon --old-d{,irs}
+                    --no-{blocking-io,detach,whole-file,inc-recursive,i-r}' -X '--no-OPTION'
+            # We didn't find any options using _comp_compgen_help, try _usage for BSD style usage
+            else
+                _comp_compgen_usage
+            fi
             [[ ${COMPREPLY-} == *= ]] || compopt +o nospace
             ;;
         *:*)

test/t/test_rsync.py

@@ -17,9 +17,10 @@ def test_2(self, completion):
     def test_3(self, completion):
         assert completion == "rsh ssh".split()
 
-    @pytest.mark.complete("rsync --", require_cmd=True)
+    @pytest.mark.complete("rsync --", require_longopt=True)
     def test_4(self, completion):
-        assert "--help" in completion
+        assert "--compress" in completion
+        assert "--timeout=" in completion
 
     @pytest.mark.parametrize(
         "ver1,ver2,result",