`path split` returns incorrect first component for drive-relative paths

[plum7x]

Bug report form

• I have done a basic search of the issue tracker to find any existing issues that are similar.
• I have checked that my version is at least the latest stable release available via my installation method.

Describe the bug

When using path split on a Windows drive-relative path (e.g., C:Desktop), the first component in the returned array incorrectly includes a trailing backslash (C:\).
In Windows, C:\ (root directory) and C: (current directory of drive C) have distinct meanings. While a standard absolute path requires retaining the separator, the command should not automatically append characters that were not originally present in the input.

How to reproduce

~> 'C:\Users\UserName' | path split
╭───┬──────────╮
│ 0 │ C:\      │
│ 1 │ Users    │
│ 2 │ UserName │
╰───┴──────────╯
~> 'C:Desktop' | path split
╭───┬─────────╮
│ 0 │ C:\     │ # Bug: Backslash is incorrectly appended
│ 1 │ Desktop │
╰───┴─────────╯

Expected behavior

path split should preserve the drive letter exactly as inputted without auto-completing it into a root path.

~> 'C:\Users\UserName' | path split
╭───┬──────────╮
│ 0 │ C:\      │
│ 1 │ Users    │
│ 2 │ UserName │
╰───┴──────────╯
~> 'C:Desktop' | path split
╭───┬─────────╮
│ 0 │ C:      │ # Expected: Stays 'C:' without the '\'
│ 1 │ Desktop │
╰───┴─────────╯

Configuration

~> version | transpose key value | to md --pretty

key	value
version	0.114.1
major	0
minor	114
patch	1
branch
commit_hash	0df4ca2
build_os	windows-x86_64
build_target	x86_64-pc-windows-msvc
rust_version	rustc 1.95.0 (59807616e 2026-04-14)
rust_channel	1.95.0-x86_64-pc-windows-msvc
cargo_version	cargo 1.95.0 (f2d3ce0bd 2026-03-21)
build_time	2026-07-11 16:22:26 +00:00
build_rust_channel	release
allocator	standard
features	default, lsp, mcp, network, plugin, rustls-tls, sqlite, trash-support
installed_plugins
experimental_options	example=false, dc-glob=false, reorder-cell-paths=true, pipefail=true, enforce-runtime-annotations=true, native-clip=false, cell-path-types=false

[fdncred]

I wonder if both outputs on Windows should just say C: instead of appending a backslash to one and not the other?

[plum7x]

I think this is legacy behavior that hardly anyone uses anymore. But if you want to return C: as the first component when splitting, then you also need to fix the path combination method. Just use the directory separator to join the components.

Current behavior:

~> ['C:' 'path' 'to' 'item'] | path join
C:path\to\item

Change of behavior:

~> ['C:' 'path' 'to' 'item'] | path join
C:\path\to\item

[fdncred]

I generally consider 'C:Desktop' as improper. Where is it used that way?

[plum7x]

CMD

C:\Users\UserName>cd /d D:\

# show all subitem under C:\Users\UserName\Desktop
D:\>dir C:Desktop

[plum7x]

path expand is also
Current behavior:

~> 'C:' | path expand
C:\Users\UserName

Change of behavior:

~> 'C:' | path expand
C:\

[fdncred]

Even if we got the parsing right, nushell doesn't know about C:Desktop and would try to do C:\Desktop which would probably fail.

[plum7x]

Yes, nushell doesn't remember the current location of the drive.

~> cd ..
C:\Users> cd D:\test
D:\test> 'C:' | path expand
C:\
D:\test> 'D:' | path expand
D:\test

[fdncred]

I'm not sure what you're trying to tell me but nushell wouldn't know you meant C:\Users\UserName\Desktop from doing ls C:Desktop from your D:\ drive no matter what your last directory in C:\ drive was.