Powershell query features returns wrong result

Question

I'm currently writing a powershell script which upgrades a set of solutions then a set of features from those solutions.

After the solution upgrades everything looks great until I Call QueryFeatures which proceeds to return an empty result set.

 # This is just sample code
 $site.QueryFeatures((Get-SPFeature | Where { $_.DisplayName -match "$FeatureName" } | Select -First 1).Id, $true)

I've tried disposing the site before use then creating a new site with new-object, and even Clearing the Object Model Cache. The only thing that works is to open a new powershell window and issuing the same command.

However this is part of a long running script so this obviously isn't the best solution. Has anyone run into this issue before?

Answer 1

It's a common issue when writing deployment scripts for SharePoint in PowerShell that often you need to spawn a new PowerShell in order to:

• Get rid of cahcing
• Get a clean AppDomain without old version of dlls loaded

The version of the dlls is going to be your next problem as I assume you're going to call Upgrade on the returned features, which might want to call into a FeatureReceiver which needs to be the new version.

So it's common to write the main script as a series of:

powershell -noexit -command &'Add-PSSnapin Microsoft.SharePoint.PowerShell -ErrorAction SilentlyContinue;substep.ps1' -sta

Answer 2

Could be a timing issue. Stick a 60 second wait in your script just before this point and see if that helps