Internals: Fail with clear error message if scripts not allowed by PS execuction policy (#2)

[markheckmann]

Fail with clear error message if PowerShell (PS) execution strategy does not allow running scripts in Windows (#2).

---

BEFORE

Reason for failure is unclear for user.

library(doconv)

file <- system.file(package = "doconv", "doc-examples/example.pptx")
out <- pptx2pdf(input = file, output = tempfile(fileext = ".pdf"))
#> Error: could not convert C:/Users/heckm/AppData/Local/R/win-library/4.4/doconv/doc-examples/example.pptx

file <- system.file(package = "doconv", "doc-examples/example.docx")
out <- docx2pdf(input = file, output = tempfile(fileext = ".pdf"))
#> Error: could not convert C:/Users/heckm/AppData/Local/R/win-library/4.4/doconv/doc-examples/example.docxDie Datei "C:\Users\heckm\AppData\Local\Temp\RtmpiSs1xl\file34605f593a78.ps1" kann nicht geladen werden, da die 
#> Ausfhrung von Skripts auf diesem System deaktiviert ist. Weitere Informationen finden Sie unter 
#> "about_Execution_Policies" (https:/go.microsoft.com/fwlink/?LinkID=135170).
#>     + CategoryInfo          : Sicherheitsfehler: (:) [], ParentContainsErrorRecordException
#>     + FullyQualifiedErrorId : UnauthorizedAccess

docx_out <- tempfile(fileext = ".docx")
file.copy(file, docx_out)
#> [1] TRUE
docx_update(input = docx_out)
#> Error: could not update C:/Users/heckm/AppData/Local/Temp/RtmpiSs1xl/file3460204023fd.docx

NEW

User is advised what to do.

library(doconv)

file <- system.file(package = "doconv", "doc-examples/example.pptx")
out <- pptx2pdf(input = file, output = tempfile(fileext = ".pdf"))
#> Error: Conversion failed.
#> Your PowerShell execution policy 'Restricted' prevents script execution.
#> Run one of the following commands in PS as admin to enable script execution: 
#>   `Set-ExecutionPolicy Bypass`
#>   `Set-ExecutionPolicy Unrestricted`

file <- system.file(package = "doconv", "doc-examples/example.docx")
out <- docx2pdf(input = file, output = tempfile(fileext = ".pdf"))
#> Error: Conversion failed.
#> Your PowerShell execution policy 'Restricted' prevents script execution.
#> Run one of the following commands in PS as admin to enable script execution: 
#>   `Set-ExecutionPolicy Bypass`
#>   `Set-ExecutionPolicy Unrestricted`

docx_out <- tempfile(fileext = ".docx")
file.copy(file, docx_out)
#> [1] TRUE
docx_update(input = docx_out)
#> Error: Conversion failed.
#> Your PowerShell execution policy 'Restricted' prevents script execution.
#> Run one of the following commands in PS as admin to enable script execution: 
#>   `Set-ExecutionPolicy Bypass`
#>   `Set-ExecutionPolicy Unrestricted`

^{Created on 2024-10-04 with reprex v2.1.1}

[davidgohel]

thanks for the really nice improvement.