A class and function to output a basic dependency graph for installed Chocolatey packages.

Get-ChocolateyDependencies.ps1

<#
    .Synopsis
        Contains a class and function to output dependencies for one or all packages on a given system.
        
    .Description
        Contains a PackageDependencyChain class that will find dependencies for locally installed, or CCR available, packages.
        
        This can be used manually, or a tree can be shown via the Get-ChocolateyDependencies function.
        
    .Example
        .\Get-ChocolateyDependencies.ps1
        
        # Should just output a not-very-pretty dependency tree for all installed packages.
        
    .Example
        . .\Get-ChocolateyDependencies.ps1  # Dot-sourcing or pasting the file into a terminal
        Get-ChocolateyDependencies -Id vmwareworkstation
        
        # Displays a tree for a given package.
        
    .Example
        . .\Get-ChocolateyDependencies.ps1  # Dot-sourcing or pasting the file into a terminal
        [PackageDependencyChain]::new("vcredist2015").OutDependencies()
        
        # Lists a deduped list of total dependencies a given package has.
#>

class PackageDependencyChain {
    [string]$Id
    #[Nuget.Versioning.VersionRange]$Version  # Ignore this for now
    [PackageDependencyChain[]]$Dependencies

    PackageDependencyChain ($Id) {
        $NuspecPath = "$env:ChocolateyInstall\lib\$Id\$Id.nuspec"

        if (Test-Path $NuspecPath) {
            [xml]$Nuspec = Get-Content $NuspecPath
            $Namespace = [Xml.XmlNamespaceManager]::new($Nuspec.NameTable)
            $Namespace.AddNamespace("nuspec", $Nuspec.package.xmlns)

            $this.Id = $Nuspec.package.metadata.id
            $this.Dependencies = $Nuspec.SelectNodes("//nuspec:dependency", $Namespace).id
        } else {
            $QueryString = "Id eq '$Id' and IsLatestVersion"
            $QueryUrl = 'https://community.chocolatey.org/api/v2/Packages()?$filter={0}' -f [uri]::EscapeUriString($queryString)
            [xml]$Nuspec = Invoke-WebRequest $QueryUrl -UseBasicParsing  # Not actually a nuspec

            $this.Id = $Nuspec.feed.entry.title.'#text'
            $this.Dependencies = $Nuspec.feed.entry.properties.Dependencies.ForEach{ $_.Split(":")[0] }
        }
    }

    [string] DisplayTree([int]$Depth = 0, [switch]$Last) {
        $LastItemChar, $MoreItemsChar = [char]0x2514, [char]0x251C
        $BranchType = if ($Last) {
            $LastItemChar
        } else {
            $MoreItemsChar
        }
        $StringOutput = if ($Depth) {
            (" " * 4 * ($Depth - 1)) + $BranchType + "$([char]0x2500)$([char]0x2500) " + $this.Id + "`n"
        } else {
            $this.Id + "`n"
        }

        foreach ($Dependency in $this.Dependencies) {
            $StringOutput += $Dependency.DisplayTree($Depth + 1, $(($this.Dependencies.Count - 1) -eq $this.Dependencies.IndexOf($Dependency)))
        }

        # Fill in gaps between wrapped nested rows
        # $StringOutput = $StringOutput.Split("`n")
        # foreach ($Line in $StringOutput) {
        #     if (($WrapIndex = $Line.IndexOf($MoreItemsChar)) -ge 0) {
        #         foreach ($LineNumber in ($StringOutput.IndexOf($Line)+1)..$StringOutput.Count) {
        #             Write-Verbose "Checking line '$LineNumber': '$($StringOutput[$LineNumber])'" -Verbose
        #             if (($StringOutput[$LineNumber].ToCharArray())[$WrapIndex] -in @($LastItemChar, $MoreItemsChar)) {
        #                 Write-Verbose "Found closing char on '$_'" -Verbose
        #                 break
        #             }
        #             $StringOutput[$LineNumber] = -join([char[]]($StringOutput[$LineNumber])[0..($WrapIndex-1)] + '|' + ([char[]]$StringOutput[$LineNumber])[($WrapIndex+1)..$StringOutput[$LineNumber].Length])
        #         }
        #     }
        # }

        return $StringOutput -join "`n"
    }

    [string[]] OutDependencies() {
        [string[]]$Packages = foreach ($Dependency in $this.Dependencies) {
            $Dependency.OutDependencies()
        }

        return $Packages + $this.Id | Select-Object -Unique
    }
}

function Get-ChocolateyDependencies {
    <#
        .Synopsis
            Shows a tree of Chocolatey packages and their dependencies
    #>
    [CmdletBinding()]
    param(
        # If specified, only tests a specific package
        [ArgumentCompleter({
                param($1, $2, $WordToMatch, $4, $5)
                Get-ChildItem $env:ChocolateyInstall\lib | ? BaseName -Like "$WordToMatch*" | % BaseName
                if ($WordToMatch) {
                    Invoke-RestMethod -UseBasicParsing -Uri "https://community.chocolatey.org/json/JsonApi?invoke&action=GetSuggestions&SearchTerm=$WordToMatch" | ForEach-Object {
                        $_.PackageId
                    }
                }
            }
        )]
        [string]$Id,

        # If passed, doesn't list packages that are dependencies on the top layer
        [switch]$SkipTopLevelDependencies
    )
    process {
        if ($Id) {
            ([PackageDependencyChain]$Id).DisplayTree(0, $false)
        } else {
            $Packages = [PackageDependencyChain[]](Get-ChildItem $env:ChocolateyInstall\lib | % BaseName)
            if ($SkipTopLevelDependencies) {
                $Packages.Where{ $_.Id -notin $_.Dependencies.Id }.DisplayTree(0, $false)  # May need to tune this for nesting
            } else {
                $Packages.DisplayTree(0, $false)
            }
        }
    }
}

if ($MyInvocation.InvocationName -ne ".") {
    Get-ChocolateyDependencies
}