Possible Fix for `xah-open-in-external-app` Returning "positional parameter cannot be found" Error

[cutechservices]

I've been having trouble with xah-open-in-external-app in Windows since the switch to using PowerShell's "Invoke-Item" cmdlet. But I think I've found a solution.

The problem is how cmd.exe and PowerShell handle file names and directories with spaces and other characters in them, and how cmdlets, their arguments, and strings are processed.

For example, say I have a file:

e:\Home\Archives\Test Directory\2020\Blah File [Old].txt

As currently written, xah-open-in-external-app will send this following to cmd.exe:

PowerShell -Command Invoke-Item E:\Home\Archives\Test Directory\2020\Blah File [Old].txt

Which barfs with this error:

Invoke-Item : A positional parameter cannot be found that accepts argument 'Directory\2020\Blah'

To get the command to work as intended, we need to do three things:

1) We need to use the -LiteralPath argument, which treats the string containing the path as literal, and containing no PowerShell wildcards

2) We need to double-quote the cmdlet and its argument to separate it from the path to our file, and

3) We need to single-quote the fully-expanded path to our file, so PowerShell can handle the spaces.

The final command cmd.exe needs to open the example above is:

PowerShell -Command "Invoke-Item -LiteralPath" 'E:\Home\Archives\Test Directory\2020\Blah File [Old].txt'

And to get that output, I modified the PowerShell call in xah-open-in-external-app to:

(shell-command (concat "PowerShell -Command \"Invoke-Item -LiteralPath\" " "'" (shell-quote-argument (expand-file-name $fpath )) "'")))

Which works as intended for everything I've tested so far.

Also: buying your tutorial is how I learned Emacs. I really appreciate all the work you do!

[xahlee]

thank you. fixed in 7af8f1f0d2bcdb3c786ee0bafdd3a9e647ca7630

[cutechservices]

Awesome -- thanks!