PowerShell / PowerShell/PSScriptAnalyzer
PSUseOutputTypeCorrectly: Fails when using multiple output types
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Description
Steps to reproduce
The following code snippet returns to objects with different types.
function Get-Function
{
[CmdletBinding()]
[OutputType(
[System.String],
[System.UInt32])]
param ()
return [System.String] 'hello', [System.UInt32] 1
}
$myString, $myInt = Get-Function
$myString.GetType()
$myInt.GetType()
But when running the analyzer on this it hits rule PSUseOutputTypeCorrectly .
Invoke-ScriptAnalyzer -ScriptDefinition @'
function Get-Function
{
[CmdletBinding()]
[OutputType(
[System.String],
[System.UInt32])]
param ()
return [System.String] 'hello', [System.UInt32] 1
}
'@
Expected behavior
No rule should be hit since the OutputType contains two output types which is valid syntax according to this https://docs.microsoft.com/en-us/powershell/module/microsoft.powershell.core/about/about_functions_outputtypeattribute?view=powershell-5.1
Two or more output types could equal to System.Object[]. But preferably it should see if there are multiple output types, and then see how many return values there are.
Actual behavior
RuleName Severity ScriptName Line Message
-------- -------- ---------- ---- -------
PSUseOutputTypeCorrectly Information 9 The cmdlet 'Get-Function' returns an object of type '
System.Object[]' but this type is not declared in the
OutputType attribute.
Environment data
> $PSVersionTable
Name Value
---- -----
PSVersion 5.1.18890.1000
PSEdition Desktop
PSCompatibleVersions {1.0, 2.0, 3.0, 4.0...}
BuildVersion 10.0.18890.1000
CLRVersion 4.0.30319.42000
WSManStackVersion 3.0
PSRemotingProtocolVersion 2.3
SerializationVersion 1.1.0.1
> (Get-Module -ListAvailable PSScriptAnalyzer).Version | ForEach-Object { $_.ToString() }
1.18.1
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by reproducing the example with Invoke-ScriptAnalyzer and trace the PSUseOutputTypeCorrectly rule's handling of multiple OutputType values and returned values. Done means the valid function no longer produces a diagnostic, with regression coverage added wherever this rule's tests are located.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- csharp, powershell
- Domain
- tooling
- Issue type
- Bug
- Difficulty
- 3/5
- Estimated time
- 1-2 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 42/100