nushell: Nushell no longer respects file associations on Windows

Describe the bug

e.g. given some x.py and a file association of

>ASSOC .py
.py=Python.File
>FTYPE Python.File
Python.File="C:\Windows\py.exe" "%L" %*

How to reproduce

〉x.py --help
Error: nu::shell::external_command (link)

  × External command failed
   ╭─[entry #4:1:1]
 1 │ x.py --help
   · ──┬─
   ·   ╰── did you mean 'cp'?
   ╰────
  help: program not found

〉./x.py --help
Error: nu::shell::external_command (link)

  × External command failed
   ╭─[entry #5:1:1]
 1 │ ./x.py --help
   · ───┬──
   ·    ╰── can't run executable
   ╰────
  help: %1 is not a valid Win32 application. (os error 193)

Expected behavior

The file should be run using the file association. This is what happened when running via a cmd /c host shell for execution.

Screenshots

No response

Configuration

key	value
version	0.67.0
branch
commit_hash	91976988f032276ca48faff2d1ac13c079eda836
build_os	windows-x86_64
build_target	x86_64-pc-windows-msvc
rust_version	rustc 1.63.0 (4b91a6ea7 2022-08-08)
rust_channel	stable-x86_64-pc-windows-msvc
cargo_version	cargo 1.63.0 (fd9c4297c 2022-07-01)
pkg_version	0.67.0
build_time	2022-08-17 15:20:56 +00:00
build_rust_channel	release
features	database, dataframe, default, trash, which, zip
installed_plugins

Additional context

The Windows documentation for file types is https://docs.microsoft.com/en-us/windows/win32/shell/fa-file-types. If I’m reading this right, in order to read the file associations you need to read the registry directly.

About this issue

Original URL
State: closed
Created 2 years ago
Comments: 19 (18 by maintainers)

Most upvoted comments

Also of note; ./x.py should run the script in the same terminal; start x.py opens it in a new terminal window.

CAD97 on Aug 29, 2022

So we’re kindof both right, in that it is the which path executing it, but that the behavior changed after that PR when updating the dependency.

That said, the “proper” behavior is probably to

Determine the file to execute by checking the given path and the given path with exts from PATHEXT (what which is doing)
Determine how to run the file (assoc/ftype) similarly to how pwsh/cmd do; this does use the registry file associations (even in cmd!) and not the legacy ones visible through assoc/ftype. For example, try “running” a .html in cmd; ftype says iexplore.exe but it will be your actual browser choice.

The point is to “act like a shell” in terms of executing files; matching the behavior of cmd and pwsh in launching files is probably better than being “pure” and only launching directly-executables or PATHEXT executables.

CAD97 on Sep 7, 2022