Invoke-ScriptAnalyzer should implement SupportsShouldProcess

[rjmholt]

From #1476 (comment)

[SydneyhSmith]

@bergmeister we were discussing this and were thinking that since Invoke-ScriptAnalyzer does not change any state (or any script) that this might not be applicable--is there something we are missing? Thanks!

[bergmeister]

@SydneyhSmith PSSA has internal and external state (CommandInfo cache in memory and DSC module cache in user profile path on disk).
That aside, to help answer your question: the -Fix switch changes the analysed files on disk, which would be a classic use case of -Whatif. The -Recurse switch makes it analyse scripts in subfolders as well and is therefore another use cases where it currently provides information around analysed/affected files and (I think but not sure) also which rules would be run. This could be useful to know in the case of a large repo of files to be analysed without having to wait too long, which is not really about state but still useful.
If I had to redesign it for v2, I would log information of a dry run. Whether parsing is part of a dry run is questionable but I could see that being valueable as well

[bergmeister]

@SydneyhSmith After a conversation with @thomasrayner there also seems to be the case that people want to know which rules are run without having to parse the verbose output. If -WhatIf returned a rich object around the rules to be run and files to be analysed, this could be useful

[rjmholt]

Seems like Get-ScriptAnalyzerRule could also be applicable there.

Personally I'm not totally convinced that Invoke-ScriptAnalyzer should implement ShouldProcess, especially since the internal state feels to me more like an unwanted implementation detail than anything else. A linter that needs a WhatIf sounds to me like it does too much. Other commands that format files etc make sense though.

But I think this is valuable discussion, and I don't see too much harm in adding the feature. Could be useful for debugging at least.

[bergmeister]

Yes, Get-ScriptAnalyzerRule should return in its RuleInfo more details such as e.g. if a rule is run by default by Invoke-ScriptAnalyzer or Invoke-Formatter. It should also have a parameters like -Settings and the Include/ExcludeRule params to 'simulate' a run

[thomasrayner]

Elaborating on what @bergmeister said, when I run PSSA in a CI environment like Azure Pipelines, I want to be able to publish the results to the Test Results section (ideally formatted as nUnit or something else compatible, but that's not the point of this issue). For the test results to be most meaningful, I'd want consistency over which rules showed up there each time so I can track when each file violated each rule and when.

Maybe what I really want is for Get-ScriptAnalyzerRule to take a -Settings file and produce calculated output based on what rules would run given a particular psd1 settings file. I already have to wrap PSSA with Pester to get nUnit formatted results, so if I didn't have to parse my own settings and compare with the default rules, it wouldn't be too far a stretch.

[bergmeister]

Issue #1296 and #672 track that. I feel we should close the latter in favour of the former though.
There is already a script that converts a DiagnosticRecord to NUnit XML (not ideal as one would also want positive results but it's something).
https://github.com/MathieuBuisson/PowerShell-DevOps/blob/master/Export-NUnitXml/Export-NUnitXml.psm1

[thomasrayner]

Is there a larger discussion anywhere (or has there been one in the past) about how PSSA fits into CI/CD systems?

[bergmeister]

Not aware, even Steve complained to me about this one but there is the PSCodeHealth module and its Azure DevOps extension here.