Can't suppress message for a particular script

[rkeithhill]

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Steps to reproduce

Create a script with just variable definitions. This is a script you will dot source into a more complex script. Now when you analyze the script you will get a PSUseDeclaredVarsMoreThanAssignments warning. Suppressing these warnings one-by-one in such a file is a PITA and really makes this file that is supposed to be simple for my users to update, much more intimidating.

Expected behavior

I expected a single suppress message declaration at the top of the file to work:

[System.Diagnostics.CodeAnalysis.SuppressMessageAttribute('PSUseDeclaredVarsMoreThanAssigments', '', Scope="Script", Target="*")]

Actual behavior

This had no impact. The only way I can get this to work is to put this attribute (modified to remove the last two params) before every single variable declaration. And no, I don't want to disable this rule for all files, just this one file.

Environment data

> $PSVersionTable
Name                           Value
----                           -----
PSVersion                      6.2.0
PSEdition                      Core
GitCommitId                    6.2.0
OS                             Microsoft Windows 10.0.17763
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() }
1.18.0
1.17.1

[rkeithhill]

As an aside, if it isn't easy to have an attribute at the global script level, then maybe PSSA could use a comment convention e.g.:

#pragma PSScriptAnalyzer disable PSUseDeclaredVarsMoreThanAssignments
... for the rest of the script, this warning is disabled

and

#pragma PSScriptAnalyzer disable PSUseDeclaredVarsMoreThanAssignments
... for script between these pragmas, the warning is disabled
#pragma PSScriptAnalyzer enable PSUseDeclaredVarsMoreThanAssignments

The problem, I think, is that for this to work it would require a change to PowerShell (maybe v7) to recognize #pragma directives and put them in the AST. This syntax could be generalized for use by any module willing to look for such pragma's in a script's AST e.g.:

#pragma <pragma-name> <pragma-arguments>
# For PowerShell modules, you'd use this format:
#pragma <module-name> <module-specific-directive> <arg>[,<arg>]

See https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/preprocessor-directives/preprocessor-pragma and https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/preprocessor-directives/preprocessor-pragma-warning

Now, these are not "compiler directives" so perhaps pragma isn't the best name but I still think the concept would be easier to work with and more flexible (disabling and re-enabling around sections of the script) than using a SuppressMessage attribute.

[Jaykul]

Are you putting that attribute on a param() @rkeithhill ?

[rkeithhill]

No. Just at the top of the file. I tried putting it on an empty param () at the beginning of the file but that didn't work either.

[Jaykul]

Yeah, actually, just tested ... it looks like the suppression only works on named functions.

[bergmeister]

PSSA is looking for a FunctionAst, therefore if you put a param() at the top of that file (the attribute goes on top), then that does work:

[System.Diagnostics.CodeAnalysis.SuppressMessageAttribute('PSUseDeclaredVarsMoreThanAssignments', '')]
param()

$unused1 = Get-Foo
$unused2 = Get-Bar

Issue #849 tracks more sophisticated suppression syntax

[oising]

Oh, and also: #1295

[SydneyhSmith]

Going to mark this a duplicate and track this issue with #849 and #1295