Paths on Windows are invalid

[71]

Describe the bug
On Windows, the extended path with UNC prefix are used to canonicalize paths (e.g in the root directory at the top, or in output of commands). This causes issues

To Reproduce
Using the following Powershell Core function, try to :cd into a directory.

function br
{
    $TempFile = New-TemporaryFile
    broot.exe --outcmd $TempFile $Args

    if (!$?)
    {
        Remove-Item -Force $TempFile
        return $LASTEXITCODE
    }

    $CommandToExecute = Get-Content $TempFile
    Remove-Item -Force $TempFile
    Invoke-Expression $CommandToExecute
}

An error will be shown, indicating that the path \\?\A:\Foo does not exist (even though A:\Foo does exist).

Expected behavior
Normal (usable) links with no UNC prefix should be used, since most commands do not support those prefixes.

Configuration

• OS: Windows
• Version: 10.0.18362

Additional context
As first reported here, the problem is that Broot calls std::fs::canonicalize, which returns a path like \\?\C:\Users\71, instead of C:\Users\71. Therefore using :cd inside Broot will write a command cd '\\?\A:\foo', which will confuse PowerShell (and most commands in general).

A workaround is to execute $Command.Replace('\\?\', '') instead of $Command.

In the end, the script I ended up using is:

function br
{
    $TempFile = New-TemporaryFile
    broot.exe --outcmd $TempFile $Args

    if (!$?)
    {
        Remove-Item -Force $TempFile
        return $LASTEXITCODE
    }

    $CommandToExecute = Get-Content $TempFile
    Remove-Item -Force $TempFile
    Invoke-Expression $CommandToExecute.Replace('\\?\', '')
}

However, it looks like this does not work in all cases. This crate attempts to make the transformation in a smart way, but I wonder what should happen when it judges that the UNC prefix cannot be stripped.

[Canop]

I can't test on windows so I'll need your help for that (you already wrote a beautiful bug report).

Do you think we could just solve the problem by issuing our own canonicalization at broot launch?

Something like this:

#[cfg(not(windows))]
fn canonicalize_root(root: &Path) -> io::Result<PathBuf> {
    root.canonicalize()
}

#[cfg(windows)]
fn canonicalize_root(root: &Path) -> io::Result<PathBuf> {
    Ok(
        if root.is_relative() {
            env::current_dir()?.join(root)
        } else {
            root.to_path_buf()
        }
    )
}

(maybe also solving links but there's probably not much more to do)

[Canop]

note: the referenced commit isn't on master right now (it's in a "no-unce" branch)

[stinos]

I'd be happy to help testing/adding docs. But I can't get started: I defined the br function but still when launching it all I get is

Broot should be launched using a shell function (see https://github.com/Canop/broot for explanations).
The function is either missing, old or badly installed.
Can I install it now? [Y n]

Removing C:\Users\<user>\AppData\Roaming\dystroy\broot\data\launcher\bash\1.
Writing br shell function in C:\Users\<user>\AppData\Roaming\dystroy\broot\data\launcher\bash\1.
Removing C:\Users\<user>\AppData\Roaming\dystroy\broot\config\launcher\bash\br.
Creating link from C:\Users\<user>\AppData\Roaming\dystroy\broot\config\launcher\bash\br to C:\Users\<user>\AppData\Roaming\dystroy\broot\data\launcher\bash\1.

I found neither .bashrc nor .zshrc.
If you're using bash or zsh, then installation isn't complete:
the br function initialization script won't be sourced unless you source it yourself.

You cannot call a method on a null-valued expression.
At C:\Users\<user>\Documents\WindowsPowerShell\PowerShell_profile_curhost.ps1:31 char:5
+     Invoke-Expression $CommandToExecute.Replace('\\?\', '')
+     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (:) [], RuntimeException
    + FullyQualifiedErrorId : InvokeMethodOnNull

(that last error is from the br function, I assume broot didn't return non-zero exit code making the function continue)

Any hints?

[Canop]

@stinos I just published a new version fixing the 'n' answer being ignored (a problem I discovered yesterday).

[stinos]

Can confirm that works. Just get a black screen upon launching though, @71 did you do anything special to get this working? If I get some time I'll install a Rust environment for building from source.

[lubieowoce]

@71 on my system your function crashes if broot doesn't emit a cd command, i.e the temp file is empty -- invoke-expression seems to dislike empty strings. i'm pretty new to PS, but adding a if ($command) { ... } seems to work:

function br {
    $outcmd = new-temporaryfile
    broot.exe --outcmd $outcmd $args
    if (!$?) {
        remove-item -force $outcmd
        return $lastexitcode
    }

    $command = get-content $outcmd
    if ($command) {
        # workaround - paths have some garbage at the start
        $command = $command.replace("\\?\", "", 1)
        invoke-expression $command
    }
    remove-item -force $outcmd
} 

(sorry about the renaming, i just really don't like PS's Capitalize-Everything style)

[71]

@stinos I did have to manually create the file %APPDATA%\dystroy\broot\config\launcher\installed-v1.

@lubieowoce Arh I forgot PowerShell likes to implicitly convert everything... Good catch!

[stinos]

I did have to manually create the file ...

@71 I already got the file refused there since Canop fixed the issue mentioned above, so that isn't the problem. I think it has to do with rendering/esacpe codes (it does react to Esc key for instance i.e. it's like running headless). If I launch broot in in plain cmd or PS I just get a blank screen. If I launch it in cmd running under Conemu though it printes a ton of escape codes e.g. here's an excerpt:

←[68;1H←[K←[68;1H←[48;5;235m←[38;5;252m ←[0m←[48;5;235m←[38;5;252mHit ←[0m←[48;5;235m←[38;5;178mesc←[0m←[48;5;235m←[38;5;252m to go back, ←[0m←[48;5;235m←[38;5;178menter←[0m←[48;5;235m←[38;5;252m to go up, ←[0m←[48;5;235m←[38;5;178m?←[0m←[48;5;235m←[38;5;252m for help, or a few letters to search←[0m←[48;5;235m←[38;5;252m

@Canop this is going off topic, make a new issue for this or reopen e.g. the 'Windws compatibility' one?

[Canop]

I don't want to reopen a too wide issue. I'd like clear separate issues, with reproduction steps and description of the problems, so that they can be addressed.

[lubieowoce]

how about a separate issue for powershell support? that does seem kind of off-topic here, and it'd be easier to find for people looking for a suitable br function

[stinos]

An error will be shown, indicating that the path \?\A:\Foo does not exist (even though A:\Foo does exist).

Which PS version? I cannot reproduce this, i.e. running Windows 10 version 1803 with PSVersion 5.1.17134.590 the command cd \\?\A:\Foo works, though leads to cd'ing to Microsoft.PowerShell.Core\FileSystem::\\?\A:\Foo. Don't know when this changed exactly but since a while Windows has extended support for paths like this, e.g. when broot runs $EDITOR \\?\A:\myfile.txt that also works for me.

[71]

@stinos I'm on PS Core (v6.2.2, Windows 10 version 1903), which is a little less Windows-focused than regular PowerShell. cd \\?\A:\Foo doesn't work, cd A:\Foo does. Maybe there's a setting somewhere else...