Rule Request: Warn Against Special Characters that PowerShell Accepts

[cpmcgrath]

Powershell 7 supports the use of Em Dash ( – ) for parameter prefixes, while Windows Powershell doesn't and can cause errors such as

Invoke-Command –ComputerName $Computer ...
–ComputerName $Computer
The string is missing the terminator: "

I'm not sure how but in the last month a good dozen Em Dashes were accidentally added to my codebase.

As Em Dashes are almost impossible to notice in a fix width font, I think it should be considered best practice to never use them and put a big error/warning on screen when you come across one.

[rjmholt]

This feature request is best suited to PSScriptAnalyzer, which provides the warnings for the PowerShell extension.

Just to clarify:

• Windows PowerShell does support em-dashes, but only when it recognises the file's encoding (Notice that the particular reason it fails is because it also supports “ as an opening quote)
• The em-dashes may always have been present and your file's encoding changed, or the can also be inserted when copy/pasting through things like MS Word
• The actual underlying issue is that VSCode has encoded your file as UTF-8 without a BOM, but Windows PowerShell needs a BOM in order to not assume that the encoding is CP-1252. Take a look at the extensive encoding document we wrote to configure VSCode better to prevent this from happening in the future

[bergmeister]

There is also this VS-Code extension for interactive linting: https://marketplace.visualstudio.com/items?itemName=nachocab.highlight-dodgy-characters

[rjmholt]

And I should also spruik UseBOMForUnicodeEncodedFile

[rjmholt]

This rule could, in its warning, link to https://docs.microsoft.com/powershell/scripting/dev-cross-plat/vscode/understanding-file-encoding

[notgriffin]

Referencing #1880, there should also be a warning when any of the following unicode characters are used to quote a string: U+201C, U+201D, U+201F, U+2019, U+301D, U+301E, U+301F, U+FF02, U+201A, U+2018, U+201B, U+2758, or U+275C.

[iRon7]

Just scanning for Rule Request in:title and apparently I created a duplicate (specifically for the em-dash in parameters), see: #1932