PowerShell / PowerShell/PSScriptAnalyzer
Suppression with `SuppressMessageAttribute` is completely broken for variables
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- Dominant language
- C#
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Description
Steps to reproduce
Consider this code:
$foo = "never used" # Should generate PSUseDeclaredVarsMoreThanAssignments
$global:var1 = $null # Should generate PSAvoidGlobalVars
Now let's try to add these suppressions:
[Diagnostics.CodeAnalysis.SuppressMessage('NonexistentRule', '')]
$foo = "never used" # Should still generate PSUseDeclaredVarsMoreThanAssignments
[Diagnostics.CodeAnalysis.SuppressMessage('PSAvoidGlobalVars', '')]
$global:var1 = $null # Should NOT generate PSAvoidGlobalVars
Expected behavior
I should still see the PSUseDeclaredVarsMoreThanAssignments warning, but not the PSAvoidGlobalVars one.
Actual behavior
The opposite happens, the first message is suppressed, but the second is not:
RuleName Severity ScriptName Line Message
-------- -------- ---------- ---- -------
PSAvoidGlobalVars Warning Test.ps1 5 Found global variable 'global:var1'.
Environment data
> $PSVersionTable
Name Value
---- -----
PSVersion 7.4.5
PSEdition Core
GitCommitId 7.4.5
OS Microsoft Windows 10.0.22631
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() }
1.23.0
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 running the PowerShell reproduction against PSScriptAnalyzer 1.23.0 and trace how SuppressMessageAttribute is handled for variables. Compare rule-name matching for NonexistentRule and PSAvoidGlobalVars; done means the nonexistent rule does not suppress PSUseDeclaredVarsMoreThanAssignments, while the valid rule suppresses PSAvoidGlobalVars.
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
- Clearly specified
- Newbie friendliness
- 45/100