'#Requires -Assembly' does not have any effect

[Mettcon]

Nothing get's loaded and it throws no error. No matter if it's valid input or not.
With Add-Type -Assembly 'Name.For.Assembly, Version=1.0.0.0, Culture=neutral, PublicKeyToken=123' could be loaded.
Requires for Administrator and Modules work like expected.

Steps to reproduce

@"
#Requires -RunAsAdministrator
#Requires -Assembly 'Name.For.Assembly, Version=1.0.0.0, Culture=neutral, PublicKeyToken=123'
Write-Host 'bla'
"@ > RequiresTest.ps1

Expected behavior

Expected it to work like Requires -Module ModuleName

Actual behavior

Like mentioned above, nothing happens.
The following showed no difference before and after execution

[System.AppDomain]::CurrentDomain.GetAssemblies() | select Fullname

Environment data

Name                           Value
----                           -----
PSVersion                      7.0.0-preview.5
PSEdition                      Core
GitCommitId                    7.0.0-preview.5
OS                             Microsoft Windows 10.0.14393
Platform                       Win32NT
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0…}
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1
WSManStackVersion              3.0

Name                           Value
----                           -----
PSVersion                      5.1.14393.206
PSEdition                      Desktop
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
BuildVersion                   10.0.14393.206
CLRVersion                     4.0.30319.42000
WSManStackVersion              3.0
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1

[iSazonov]

@Mettcon Please look #5022 and referenced there RFC.

[vexx32]

@iSazonov does the using assembly alternative permit a fully qualified assembly name?

[iSazonov]

Yes, #5022 and PowerShell/PowerShell-RFC#122 reject #Requires -Assembly
Tracking issues #9929 #6653

This issue has been marked as duplicate and has not had any activity for 1 day. It has been closed for housekeeping purposes.

[xtqqczze]

@iSazonov It is unclear from these issues whether or not #Requires -Assembly should be supported. Documentation suggests there is support, but this issue states the statement has no effect.

If #Requires -Assembly is not supported, than we should throw an error instead of failing silently.

[iSazonov]

@xtqqczze What is a behavior on Windows PowerShell 5?

[xtqqczze]

@iSazonov According to MicrosoftDocs/PowerShell-Docs#4518, the #Requires -Assembly feature was present in Windows PowerShell 5.1 (and likely earlier).

However, my tests in Windows PowerShell 5.1 show the behaviour is the same, i.e. nothing is loaded and no error is thrown.

[iSazonov]

Perhaps @rjmholt could comment - should we remove the parameter?

[rjmholt]

I suspect it remains for compatibility with PS 5.1 -- my guess is that's been discussed elsewhere, but can't remember.

Basically:

• using assembly is preferred to #require -Assembly because it should try to load something rather than just fail if it's not loaded already. #require has a tradition of being an assertion rather than performing an action, and also presents as a comment pragma and isn't stored in an AST, meaning it's not as good a fit.
• But because acceptance for the syntax (even if it does nothing) was added in PS 5.1, removing it would cause parse errors for scripts that would otherwise "just work" in migration from 5.1 to 7. So given the choice between a wart and a hard failure, the wart was chosen.

I think the question remains open for whether it should be removed for PS vNext

[iSazonov]

my guess is that's been discussed elsewhere, but can't remember.

It is your RFC :-)

I think we should update docs with "that currently it is not work on 5 and 7 versions and will be probably removed in future."