PSShouldProcess behavior allows for unsafe code to pass where it should fail

Steps to reproduce

The following function will pass PSShouldProcess

function Test-Fail {
    [CmdletBinding(SupportsShouldProcess)]
    param ()
    process {
        Remove-Item -Path C:\temp\a_testy.txt -Force -Confirm:$false -ErrorAction SilentlyContinue
    }
}

@seeminglyscience pointesd me to this
https://github.com/PowerShell/PSScriptAnalyzer/blob/a7d23f7f4dbf4ee92077f5471e28ca334caef429/Rules/UseShouldProcessCorrectly.cs#L245-L267

Where it is checking upstream functions for supports should process. While on the surface it may seem like a good idea to allow the upstream functions to handle the confirmation, this allows for some unsafe code to pass where it should fail.

IMO, the best course would be to always warn when $PSCmdlet.ShouldProcess() is not present in the function itself and require suppression when allowing the upstream functions to handle the confirmation.

Expected behavior

Either a warning or the requirement to suppress PSShouldProcess

Actual behavior

Test passes

Environment data

> $PSVersionTable
Name                           Value
----                           -----
PSVersion                      5.1.16299.251
PSEdition                      Desktop
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
BuildVersion                   10.0.16299.251
CLRVersion                     4.0.30319.42000
WSManStackVersion              3.0
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1
> (Get-Module -ListAvailable PSScriptAnalyzer).Version | ForEach-Object { $_.ToString() }
1.16.0
1.15.0
1.13.0
1.12.0
1.8.1
1.16.1

Rules/UseShouldProcessCorrectly.cs から始め、特に 245-267 行付近の upstream-function チェックを確認し、示されている PowerShell 関数で問題を再現します。Analyzer が $PSCmdlet.ShouldProcess() の欠落した動作を報告するか、抑制を要求することを確認し、その後、期待される警告または抑制要件のカバレッジを追加します。