create a function dir_strip_dot_for_creation to manage the /. issue

src/uu/install/src/install.rs

@@ -20,6 +20,7 @@ use uucore::display::Quotable;
 use uucore::entries::{grp2gid, usr2uid};
 use uucore::error::{FromIo, UError, UIoError, UResult, UUsageError};
 use uucore::format_usage;
+use uucore::fs::dir_strip_dot_for_creation;
 use uucore::mode::get_umask;
 use uucore::perms::{wrap_chown, Verbosity, VerbosityLevel};
 
@@ -399,12 +400,7 @@ fn directory(paths: &[String], b: &Behavior) -> UResult<()> {
                 // install -d foo/. should work and just create foo/
                 // std::fs::create_dir("foo/."); fails in pure Rust
                 // See also mkdir.rs for another occurrence of this
-                let path_to_create = if path.to_string_lossy().ends_with("/.") {
+                let path_to_create = dir_strip_dot_for_creation(path.to_path_buf());
-                    // Do a simple dance to strip the "/."
-                    Path::new(path).components().collect::<PathBuf>()
-                } else {
-                    path.to_path_buf()
-                };
                 // Differently than the primary functionality
                 // (MainFunction::Standard), the directory functionality should
                 // create all ancestors (or components) of a directory

src/uucore/src/lib/features/fs.rs

@@ -470,6 +470,20 @@ pub fn display_permissions_unix(mode: mode_t, display_file_type: bool) -> String
     result
 }
 
+// For some programs like install or mkdir, dir/. can be provided
+// Special case to match GNU's behavior:
+// install -d foo/. should work and just create foo/
+// std::fs::create_dir("foo/."); fails in pure Rust
+// See also mkdir.rs for another occurrence of this
+pub fn dir_strip_dot_for_creation(path: PathBuf) -> PathBuf {
+    if path.to_string_lossy().ends_with("/.") {
+        // Do a simple dance to strip the "/."
+        Path::new(&path).components().collect::<PathBuf>()
+    } else {
+        path.to_path_buf()
+    }
+}
+
 #[cfg(test)]
 mod tests {
     // Note this useful idiom: importing names from outer (for mod tests) scope.