Add the . and .. entries to glob()

os_scandir() and os_scandir_next() skip over those, because of the
unverlying libuv funcitons behaviour.

Fixes #2954

src/nvim/path.c

@@ -481,6 +481,28 @@ static size_t path_expand(garray_T *gap, const char_u *path, int flags)
   return do_path_expand(gap, path, 0, flags, false);
 }
 
+static const char *scandir_next_with_dots(Directory *dir)
+{
+  static int count = 0;
+  const char *entry = NULL;
+  if (dir == NULL) {
+    count = 0;
+  } else {
+    count += 1;
+    if (count == 1) {
+      entry = ".";
+    } else if (count == 2) {
+      entry = "..";
+    } else {
+      entry = os_scandir_next(dir);
+      if (entry == NULL) {
+        count = 0;
+      }
+    }
+  }
+  return entry;
+}
+
 /// Implementation of path_expand().
 ///
 /// Chars before `path + wildoff` do not get expanded.
@@ -597,11 +619,12 @@ static size_t do_path_expand(garray_T *gap, const char_u *path,
   *s = NUL;
 
   Directory dir;
-  // open the directory for scanning
+  if (os_scandir(&dir, *buf == NUL ? "." : (char *)buf)
-  if (os_scandir(&dir, *buf == NUL ? "." : (char *)buf)) {
+      || os_isdir(*buf == NUL ? (char_u *)"." : (char_u *)buf)) {
     // Find all matching entries.
     char_u *name;
-    while((name = (char_u *) os_scandir_next(&dir))) {
+    scandir_next_with_dots(NULL);
+    while((name = (char_u *) scandir_next_with_dots(&dir)) && name != NULL) {
       if ((name[0] != '.' || starts_with_dot)
           && ((regmatch.regprog != NULL && vim_regexec(&regmatch, name, 0))
               || ((flags & EW_NOTWILD)

test/functional/eval/glob_spec.lua

@@ -0,0 +1,21 @@
+local helpers = require('test.functional.helpers')
+local clear, execute, eval, eq = helpers.clear, helpers.execute, helpers.eval, helpers.eq
+
+before_each(function()
+  clear()
+  lfs.mkdir('test-glob')
+  execute('cd test-glob')
+end)
+
+after_each(function()
+  lfs.rmdir('test-glob')
+end)
+
+describe('glob()', function()
+  it("glob('.*') returns . and .. ", function()
+    eq({'.', '..'}, eval("glob('.*', 0, 1)"))
+  end)
+  it("glob('*') returns an empty list ", function()
+    eq({}, eval("glob('*', 0, 1)"))
+  end)
+end)