fix(cd): Complete from . on empty CDPATH entry (#1527)

Author: jmou

completions-core/cd.bash

@@ -38,6 +38,7 @@ _comp_cmd_cd__compgen_cdpath()
     local paths dirs _d
     _comp_split -F : paths "$CDPATH"
     for _p in "${paths[@]}"; do
+        _p="${_p:-.}"
         # create an array of matched subdirs
         _comp_compgen -v dirs -c "$_p/$cur" -- -d &&
             for _d in "${dirs[@]}"; do

test/t/test_cd.py

@@ -51,3 +51,15 @@ def test_cdable_vars_2(self, bash):
             bash_env.write_variable("foo2", "shared/default")
             completion = assert_complete(bash, "cd f")
             assert completion == ["foo1", "foo2"]
+
+    @pytest.mark.complete("cd ", cwd="shared/default", env=dict(CDPATH=":.."))
+    def test_cdpath_leading_colon(self, completion):
+        assert completion == [
+            ".ssh/",
+            "bar bar.d/",
+            "bin/",
+            "default/",
+            "empty_dir/",
+            "foo.d/",
+            "ld.so.conf.d/",
+        ]