fs.stat or fs.lstat throws unknown error on some files (reparse point)

[karthiknadig]

• Version: v12.16.2
• Platform: 64 bit Microsoft Windows 10 [Version 10.0.18362.778]
• Subsystem: fs

What steps will reproduce the bug?

1. Check if %USERPROFILE%\AppData\Local\Microsoft\WindowsApps exists.
2. Install https://www.microsoft.com/en-us/p/python-38/9mssztt1n39l
3. Call fs.statSync("c:\\Users\\kanadig\\AppData\\Local\\Microsoft\\WindowsApps\\python.exe")

How often does it reproduce? Is there a required condition?

This repros 100%, make sure you are calling it on the files under %USERPROFILE%\AppData\Local\Microsoft\WindowsApps\ with 0 size.

What is the expected behavior?

Should not throw exception.

What do you see instead?

> fs.statSync("c:\\Users\\bpasero\\AppData\\Local\\Microsoft\\WindowsApps\\GameBarElevatedFT_Alias.exe")                 
Thrown:                                                                                                                  
{ Error: UNKNOWN: unknown error, stat 'c:\Users\bpasero\AppData\Local\Microsoft\WindowsApps\GameBarElevatedFT_Alias.exe' 
    at Object.statSync (fs.js:855:3)                                                                                     
  errno: -4094,                                                                                                          
  syscall: 'stat',                                                                                                       
  code: 'UNKNOWN',                                                                                                       
  path:                                                                                                                  
   'c:\\Users\\bpasero\\AppData\\Local\\Microsoft\\WindowsApps\\GameBarElevatedFT_Alias.exe' }                           
> fs.lstatSync("c:\\Users\\bpasero\\AppData\\Local\\Microsoft\\WindowsApps\\GameBarElevatedFT_Alias.exe")                
Thrown:                                                                                                                  
{ Error: UNKNOWN: unknown error, lstat 'c:\Users\bpasero\AppData\Local\Microsoft\WindowsApps\GameBarElevatedFT_Alias.exe'
    at Object.lstatSync (fs.js:845:3)                                                                                    
  errno: -4094,                                                                                                          
  syscall: 'lstat',                                                                                                      
  code: 'UNKNOWN',                                                                                                       
  path:                                                                                                                  
   'c:\\Users\\bpasero\\AppData\\Local\\Microsoft\\WindowsApps\\GameBarElevatedFT_Alias.exe' }                           
>     

Additional information

See microsoft/vscode#95828

[bzoz]

Those are IO_REPARSE_TAG_APPEXECLINK reparse points and currently, libuv does not support those. Nothing we cannot fix 😉

[bzoz]

A fix for this landed in libuv, it should make it way to Node rather soon.

The stat calls will probably still not work though. Those links usualy point to the C:\Program Files\WindowsApps folder that is not normally accessible, even after elevating. lstat should be fine, the added libuv test lstats the%LOCALAPPDATA%\Microsoft\WindowsApps folder.

[bzoz]

Fixed by #33446

[karthiknadig]

This is not fixed. I can repro it with the latest release.