PSUseOutputTypeCorrectly complains "... type is not declared in the OutputType attribute" even though it is

Steps to reproduce

PSScriptAnalyzer is complaining about a missing OutputType attribute, even though I did set it correctly. See PSScriptAnalyzer CI comment under my commits: https://github.com/jantari/LSUClient/commit/a6c2fcc1622aa221d0be73debb4a97baea7b36b5

Easiest way to reproduce is test with my exact file:

mkdir test-pssa
curl.exe "https://raw.githubusercontent.com/jantari/LSUClient/develop/public/Install-LSUpdate.ps1" -o .\test-pssa\Install-LSUpdate.ps1
Import-Module PSScriptAnalyzer -RequiredVersion 1.20.0 # Latest
Invoke-ScriptAnalyzer -Path .\test-pssa -ExcludeRule PSAvoidTrailingWhitespace -Recurse -Verbose

Expected behavior

PSScriptAnalyzer should have no complaints.

Actual behavior

RuleName                            Severity     ScriptName Line  Message
--------                            --------     ---------- ----  -------
PSUseOutputTypeCorrectly            Information  Install-LS 93    The cmdlet 'Install-LSUpdate' returns an object of type
                                                 Update.ps1       'PackageInstallResult' but this type is not declared in the
                                                                  OutputType attribute.
PSUseOutputTypeCorrectly            Information  Install-LS 125   The cmdlet 'Install-LSUpdate' returns an object of type
                                                 Update.ps1       'PackageInstallResult' but this type is not declared in the
                                                                  OutputType attribute.

Environment data

Issue is reproducible under both:

> $PSVersionTable
Name                           Value
----                           -----
PSVersion                      7.2.1
PSEdition                      Core
GitCommitId                    7.2.1
OS                             Microsoft Windows 10.0.22538
Platform                       Win32NT
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0…}
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1
WSManStackVersion              3.0

> (Get-Module -ListAvailable PSScriptAnalyzer).Version | ForEach-Object { $_.ToString() }
1.20.0
1.19.1

and:

> $PSVersionTable
Name                           Value
----                           -----
PSVersion                      5.1.22538.1000
PSEdition                      Desktop
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
BuildVersion                   10.0.22538.1000
CLRVersion                     4.0.30319.42000
WSManStackVersion              3.0
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1

> (Get-Module -ListAvailable PSScriptAnalyzer).Version | ForEach-Object { $_.ToString() }
1.19.0
1.20.0
1.19.1

[jantari]

Woah, that is silly. I had picked up the “specify the type name as a string” syntax somewhere a long time ago and this was the first time ever that PSSA complained about / didn’t accept it.

I’ve been doing this wrong the entire time (and many many more times in other projects / scripts …)

well damn … but thanks a lot for clearing that up. I can’t remember where I got this syntax from, but you’ve got me questioning everything now haha

SOLVED 🎉

[bergmeister]

Fair enough, it seems that if I added [CmdletBinding()] in my examples, it would’ve worked. However, what is happening here I think is that at the time of analysing it, it does not know about the type and cannot resolve it. If you imported the module that defined this type before running Invoke-ScriptAnalyzer you would not be getting this false positive, simple test by running class PackageInstallResult {} to define this type proves that. Using brackets instead of single quotes make ScriptAnalyzer not return a false positive either so definitely a workaround as well for now. I will take a detailed look later whether this rule could be tweaked.