Optimize-Dependency.ps1

class PSEquality : System.Collections.Generic.EqualityComparer[PSObject] {
    [scriptblock]$Comparer = { $_ }

    [bool] Equals([PSObject]$first, [PSObject]$other) {
        return ($first | ForEach-Object $this.Comparer) -eq ($other | ForEach-Object $this.Comparer)
    }

    [int] GetHashCode([PSObject]$module) {
        return $module.GetHashCode()
    }
}

function Optimize-Dependency {
    <#
        .SYNOPSIS
            Optimize a set of objects by their dependencies
        .EXAMPLE
            Find-Module TerminalBlocks, PowerLine |
                Optimize-Dependency -Properties Name, Version -Dependency {
                    $_.Dependencies.Name.ForEach{ Find-Module $_ }
                }
    #>
    [Alias("Sort-Dependency")]
    [OutputType([Array])]
    [CmdletBinding(DefaultParameterSetName = "ByPropertyFromInputObject")]
    param(
        # The path to a RequiredModules file
        [Parameter(Mandatory, ValueFromPipelineByPropertyName, ParameterSetName = "CustomEqualityFromPath")]
        [Parameter(Mandatory, ValueFromPipelineByPropertyName, ParameterSetName = "ByPropertyFromPath")]
        [string]$Path,

        # The objects you want to sort
        [Parameter(Mandatory, ValueFromPipeline, ParameterSetName = "CustomEqualityFromInputObject")]
        [Parameter(Mandatory, ValueFromPipeline, ParameterSetName = "ByPropertyFromInputObject")]
        [PSObject[]]$InputObject,

        # A list of properties used with Compare-Object in the default equality comparer
        # Since this is in RequiredModules, it defaults to "Name", "Version"
        [Parameter(ValueFromPipelineByPropertyName, ParameterSetName = "ByPropertyFromInputObject")]
        [Parameter(ValueFromPipelineByPropertyName, ParameterSetName = "ByPropertyFromPath")]
        [string[]]$Properties = @("Name", "Version"),

        # A custom implementation of the equality comparer for the InputObjects
        # Must accept two arguments, and return $true if they are equal, $false otherwise
        # InputObjects will only be added to the output if this returns $false
        # The default EqualityFilter compares based on the $Properties
        [Parameter(Mandatory, ValueFromPipelineByPropertyName, ParameterSetName = "CustomEqualityFromInputObject")]
        [Parameter(Mandatory, ValueFromPipelineByPropertyName, ParameterSetName = "CustomEqualityFromPath")]
        [scriptblock]$EqualityFilter = { !($args[0] | Compare-Object $args[1] -Property $Properties) },

        # A ScriptBlock to calculate the dependencies of the InputObjects
        # Defaults to a scriptblock that works for Find-Module and Get-Module
        [Parameter(ValueFromPipelineByPropertyName)]
        [ScriptBlock]$Dependency = {
            if ($_ -is [psmoduleinfo]) {
                $_.RequiredModules.Name.ForEach{ Get-Module $_ }
            } else {
                $_.Dependencies.Name.ForEach{ Find-Module $_ }
            }
        }
    )
    begin {
        if ($Path) {
            $null = $PSBoundParameters.Remove("Path")
            ImportRequiredModulesFile $Path | FindModuleVersion | Optimize-Dependency @PSBoundParameters
            return
        }
        if ($null -eq $Optimize_Dependency_Results) {
            $Optimize_Dependency_Results = [System.Collections.Generic.HashSet[PSObject]]::new([PSEquality]::new($Properties, $EqualityFilter))
        }
    }
    process {
        $null = $PSBoundParameters.Remove("InputObject")
        Write-Debug "ENTER: Optimize-Dependency $(@($Optimize_Dependency_Results).Count): $(@($InputObject | Select-Object $Properties | ForEach-Object { $_.PsObject.Properties.Value}) -join ',')"
        $InputObject | ForEach-Object $Dependency | Optimize-Dependency @PSBoundParameters
        $InputObject | Sort-Object $Properties | ForEach-Object {
            Write-Verbose "Adding $(@($_ | Select-Object $Properties | ForEach-Object { $_.PsObject.Properties.Value}) -join ',')"
            if ($Optimize_Dependency_Results.Add($_)) {
                $_
            }
        }
    }
}


# Trivial example, using already imported modules locally
Import-Module PowerShellGet -Max 2.99 -Passthru | Optimize-Dependency

# Easy example, searching the gallery
Find-Module TerminalBlocks, PowerLine | Optimize-Dependency 

# The worst case that I know of:
Find-Module VMware.PowerCLI | Optimize-Dependency

I'm going to add this to Jaykul/RequiredModules@main...feature/sorting