make ls work like dir on windows

[richardmarklund]

Description

Related issue: #6857

This fix makes the ls command work like dir on windows. This hides more files like symfiles and other dirs that the dir command does not show.

Could not create any new tests since we have a strange way to create hidden files (by creating dotfiles) and could not find any way to create symlinks.

Tests + Formatting

Make sure you've done the following, if applicable:

• Add tests that cover your changes (either in the command examples, the crate/tests folder, or in the /tests folder)
  • Try to think about corner cases and various ways how your changes could break. Cover those in the tests

Make sure you've run and fixed any issues with these commands:

• cargo fmt --all -- --check to check standard code formatting (cargo fmt --all applies these changes)
• cargo clippy --workspace --features=extra -- -D warnings -D clippy::unwrap_used -A clippy::needless_collect to check that you're using the standard code style
• cargo test --workspace --features=extra to check that all tests pass

User-Facing Changes

If you're making changes that will affect the user experience of Nushell (ex: adding/removing a command, changing an input/output type, adding a new flag):

• Get another regular contributor to review the PR before merging
• Make sure that there is an entry in the documentation (https://github.com/nushell/nushell.github.io) for the feature, and update it if necessary

[fdncred]

I'm guessing that this should be moved up so that is_hidden_dir is only available on windows.

[richardmarklund]

Thanks!

[rgwood]

Does this change always hide the directories? Or are they visible with the -a/--all flag?

[richardmarklund]

@rgwood
All is visible with -a/--all
No change there.

[rgwood]

@richardmarklund Looks like this has broken tests on Linux. Are you looking into that?

[richardmarklund]

@rgwood
Yea, noticed this morning. I'll look into it

[dandavison]

I see this is Windows-only, but what's the motivation for hiding symlinks? (other than emulating a Windows command)

Edit Oh, is it simply that Windows doesn't allow symlinks? Ignore me if so!

[rgwood]

Windows does allow symlinks (but they're a little harder to create than on *nix).

I think the logic needs to be more complex than "is it a symlink?" because cmd.exe and PowerShell do show some symlinks. However, Nu shows a few symlinks that don't show up in cmd.exe and PowerShell:

I'm not sure what exactly differentiates those symlinks from the ones shown by cmd.exe and PowerShell.

symlinks in cmd.exe dir

symlinks in PowerShell ls

[ChrisDenton]

They have the system attribute (as well as having the hidden attribute). In powershell try ls -System -Hidden.

[richardmarklund]

@rgwood @ChrisDenton
Hello and thanks for your comments. That's the way I went from the start. The problem is that I still find differences when I run ls in powershell and ls in the nushell.
Powershell:

nushell:

So here I'm filtering out everything that's either system or hidden according to:
https://docs.microsoft.com/en-us/windows/win32/fileio/file-attribute-constants

But if I also remove the symlinks it seems like its correct:

[richardmarklund]

I also have a question:
The test that is failing now seems a little strange. So we have a test that is passing and works fine named: lists_all_hidden_files_when_glob_contains_dot that creates the following structure and returns 3 which is correct according to the test.
root1.txt
root2.txt
.dotfile1
dir_a
yehuda.10.txt
jonathan.10.txt
.dotfile2
dir_b
andres.10.txt
chicken_not_to_be_picked_up.100.txt
.dotfile3

command: ls **/.* | length

The next test: lists_all_hidden_files_when_glob_does_not_contain_dot
Has the same file structure but with this command:
ls **/* | length

The test wants that to return 5, which I find a bit strange. My returns 7 which also feels strange. My intuition wanted it to be 11. But I guess the command is run inside dir_a?

Anyways, how do you want this to work? My thought was that if you specify a glob pattern then you want all the results regardless of if the command is with a dot or not.

We could either go the route of if you are specifying a glob pattern and then give the full result or you'll have to add -a/-all to get the full result regardless of the glob pattern.

What's your thought?

[ChrisDenton]

Sorry, I'm not very familiar with the code. How are you getting the attributes? The relevant attributes are on the symlink. If you have a DirEntry you can use the DirEntry::metadata method but if you just have a path you'll need to use Path::symlink_metadata (or GetFileAttributesW but that's very Windows specific).

[rgwood]

But if I also remove the symlinks it seems like its correct:

@richardmarklund See my examples here; cmd.exe and pwsh do not hide all symlinks by default.

[deoradh]

Alternatively, why not just create a switch to opt into os-specific behavior (ie, ls --os=windows)? That, then, could be aliased as desired without inducing a breaking change or affecting the portability of any scripts. It also allows that behavior to be accessed outside of any specific OS install.

[rgwood]

@richardmarklund Thanks for your work on this :). It seems like this PR has stalled so I'm going to close it for now, but if you want to pick it up again we can always reopen it.