Private/Get-GalleryModuleStatus.ps1
|
function Get-GalleryModuleStatus { <# .SYNOPSIS Compares the newest installed version of a module against the newest on the PowerShell Gallery. .DESCRIPTION Returns Installed, Available and NeedsUpdate. Installed is $null when the module is not on the machine at all, which is a different answer from "installed but old" and the caller acts on it differently: one is an install and needs consent, the other is an update and does not. Available is $null when the gallery could not be reached. NeedsUpdate is then $false, so a network failure presents as "cannot tell" rather than as a reason to reinstall. It never reports an update as available for a module that is not installed. Updatable reports whether Update-Module can move this copy forward at all. It refuses anything it did not install -- "Module 'X' was not installed by using Install-Module, so it cannot be updated" -- which covers every module that shipped with the host, wherever it sits. Windows PowerShell ships PowerShellGet 1.0.0.1 under Program Files rather than $PSHOME, so the path is not the test; whether PowerShellGet recorded the install is. A shipped copy is not stuck, but moving it forward is a side-by-side install rather than an update, and so it is an install decision. .EXAMPLE Get-GalleryModuleStatus -Name PowerShellGet #> [CmdletBinding()] [OutputType([pscustomobject])] param( [Parameter(Mandatory)] [ValidateNotNullOrEmpty()] [string] $Name ) # Indexed rather than "| Select-Object -First 1": that halts the upstream # pipeline, and inside a step action the transcript records the stop as a # TerminatingError. $present = @(Get-Module -Name $Name -ListAvailable -ErrorAction SilentlyContinue | Sort-Object Version -Descending) $installed = if ($present.Count) { [version] $present[0].Version } else { $null } # Ask PowerShellGet what it installed, rather than inferring it from the # path. Get-InstalledModule reports only what came through Install-Module, # which is exactly the set Update-Module will act on. $updatable = $false if ($present.Count -and (Get-Command Get-InstalledModule -ErrorAction SilentlyContinue)) { $updatable = [bool] (Get-InstalledModule -Name $Name -ErrorAction SilentlyContinue) } $available = $null try { $found = Find-Module -Name $Name -Repository PSGallery -ErrorAction Stop # Find-Module returns the version as a string on some PowerShellGet # versions and a [version] on others, and a prerelease carries a suffix # that [version] cannot parse. Trim the suffix and let the cast decide. $raw = "$($found.Version)" -replace '-.*$', '' if ($raw) { $available = [version] $raw } } catch { Write-Verbose "Could not ask the gallery about ${Name}: $($_.Exception.Message)" } [pscustomobject]@{ Name = $Name Installed = $installed Available = $available Updatable = $updatable NeedsUpdate = [bool] ($installed -and $available -and $available -gt $installed) } } |