(DSC) Idiomaticize resource schemas

src/dsc/psresourceget.ps1

@@ -1,6 +1,8 @@
 ## Copyright (c) Microsoft Corporation. All rights reserved.
 ## Licensed under the MIT License.
 
+using namespace System.Collections.Specialized
+
 [CmdletBinding()]
 param(
     [Parameter(Mandatory = $true)]
@@ -97,15 +99,61 @@ class PSResource {
         return $retValue
     }
 
+    [OrderedDictionary] ToData([bool]$forTest) {
+        $data = [OrderedDictionary]::new()
+
+        $data.name = $this.name
+        if (-not [string]::IsNullOrEmpty($this.version)) {
+            $data.version = $this.version
+        }
+        $data.scope = $this.scope
+        if (-not [string]::IsNullOrEmpty($this.repositoryName)) {
+            $data.repositoryName = $this.repositoryName
+        }
+        $data.preRelease = $this.preRelease
+        $data._exist = $this._exist
+
+        if ($forTest) {
+            $data._inDesiredState = $this._inDesiredState
+        }
+
+        return $data
+    }
+
+    [OrderedDictionary] ToData() {
+        return $this.ToData($false)
+    }
+
     [string] ToJson() {
-        $retVal = ($this | Select-Object -ExcludeProperty _inDesiredState | ConvertTo-Json -Compress -EnumsAsStrings)
-        Write-Trace -message "Serializing PSResource to JSON. Name: $($this.name), Version: $($this.version), Scope: $($this.scope), RepositoryName: $($this.repositoryName), PreRelease: $($this.preRelease), _exist: $($this._exist)" -level debug
-        Write-Trace -message "Serialized JSON: $retVal" -level trace
+        $retVal = $this.ToData() | ConvertTo-Json -Compress -EnumsAsStrings
+        $this.WriteSerializationTrace($retVal)
         return $retVal
     }
 
     [string] ToJsonForTest() {
-        return ($this | ConvertTo-Json -Compress -Depth 5 -EnumsAsStrings)
+        $retVal = $this.ToData($true) | ConvertTo-Json -Compress -Depth 5 -EnumsAsStrings
+        $this.WriteSerializationTrace($retVal, $true)
+        return $retVal
+    }
+
+    [void] WriteSerializationTrace([string]$json, [bool]$forTest) {
+        $pairs = @(
+            "Name: $($this.name)"
+            "Version: $($this.version)"
+            "Scope: $($this.scope)"
+            "RepositoryName: $($this.repositoryName)"
+            "PreRelease: $($this.preRelease)"
+            "_exist: $($this._exist)"
+        )
+        if ($forTest) {
+            $pairs += "_inDesiredState: $($this._inDesiredState)"
+        }
+        Write-Trace -message "Serializing PSResource to JSON. $($pairs -join ', ')" -level debug
+        Write-Trace -message "Serialized JSON: $json" -level trace
+    }
+
+    [void] WriteSerializationTrace([string]$json) {
+        $this.WriteSerializationTrace($json, $false)
     }
 }
 
@@ -154,24 +202,53 @@ class PSResourceList {
         return $true
     }
 
-    [string] ToJson() {
-        $resourceJson = if ($this.resources) { ($this.resources | ForEach-Object { $_.ToJson() }) -join ',' } else { '' }
-        $resourceJson = "[$resourceJson]"
-        $jsonString = "{'repositoryName': '$($this.repositoryName)','resources': $resourceJson}"
-        $jsonString = $jsonString -replace "'", '"'
-        $retVal =  $jsonString | ConvertFrom-Json | ConvertTo-Json -Compress -EnumsAsStrings
+    [OrderedDictionary] ToData([bool]$forTest) {
+        $data = [OrderedDictionary]::new()
+        if (-not [string]::IsNullOrEmpty($this.repositoryName)) {
+            $data['repositoryName'] = $this.repositoryName
+        }
+        if ($this.resources) {
+            [OrderedDictionary[]] $resourceData = $this.resources | ForEach-Object { $_.ToData($forTest) }
+            $data['resources'] = $resourceData
+        }
+        if ($this.trustedRepository) {
+            $data['trustedRepository'] = $this.trustedRepository
+        }
+        if ($forTest) {
+            $data['_inDesiredState'] = $this._inDesiredState
+        }
+        return $data
+    }
+    [OrderedDictionary] ToData() {
+        return $this.ToData($false)
+    }
 
-        Write-Trace -message "Serializing PSResourceList to JSON. RepositoryName: $($this.repositoryName), TrustedRepository: $($this.trustedRepository), Resources count: $($this.resources.Count)" -level debug
-        Write-Trace -message "Serialized JSON: $retVal" -level trace
+    [string] ToJson() {
+        $retVal = $this.ToData() | ConvertTo-Json -Compress -EnumsAsStrings
+        $this.WriteSerializationTrace($retVal)
 
         return $retVal
     }
 
     [string] ToJsonForTest() {
-        Write-Trace -message "Serializing PSResourceList to JSON for test output. RepositoryName: $($this.repositoryName), TrustedRepository: $($this.trustedRepository), Resources count: $($this.resources.Count)" -level debug
-        $jsonForTest = $this | ConvertTo-Json -Compress -Depth 5 -EnumsAsStrings
-        Write-Trace -message "Serialized JSON: $jsonForTest" -level trace
-        return $jsonForTest
+        $retVal = $this.ToData($true) | ConvertTo-Json -Compress -EnumsAsStrings
+        $this.WriteSerializationTrace($retVal, $true)
+        return $retVal
+    }
+
+    [void] WriteSerializationTrace([string]$json, [bool]$forTest) {
+        $preamble = 'Serializing PSResourceList to JSON'
+        $preamble += $forTest ? ' for test output.' : '.'
+        $pairs = @(
+            "repositoryName: $($this.repositoryName)"
+            "trustedRepository: $($this.trustedRepository)"
+            "resourcesCount: $($this.resources.Count)"
+        )
+        Write-Trace -message "$preamble $($pairs -join ', ')" -level debug
+        Write-Trace -message "Serialized JSON: $json" -level trace
+    }
+    [void] WriteSerializationTrace([string]$json) {
+        $this.WriteSerializationTrace($json, $false)
     }
 }
 
@@ -213,8 +290,28 @@ class Repository {
         $this.repositoryType = 'Unknown'
     }
 
+    [OrderedDictionary] ToData([bool]$forTest) {
+        $data = [OrderedDictionary]::new()
+        $data['name'] = $this.name
+        if (-not [string]::IsNullOrEmpty($this.uri)) {
+            $data['uri'] = $this.uri
+        }
+        $data['trusted'] = $this.trusted
+        $data['priority'] = $this.priority
+        if (-not [string]::IsNullOrEmpty($this.repositoryType)) {
+            $data['repositoryType'] = $this.repositoryType
+        }
+        $data['_exist'] = $this._exist
+
+        return $data
+    }
+    [OrderedDictionary] ToData() {
+        return $this.ToData($false)
+    }
+
     [string] ToJson() {
-        return ($this | ConvertTo-Json -Compress -EnumsAsStrings)
+        $retVal = $this.ToData() | ConvertTo-Json -Compress -EnumsAsStrings
+        return $retVal
     }
 }
 
@@ -527,9 +624,12 @@ function ExportOperation {
             exit [ExitCode]::ExportNotImplemented
         }
         'psresourcelist' {
-            $currentUserPSResources = Get-PSResource
-            $allUsersPSResources = Get-PSResource -Scope AllUsers
-            PopulatePSResourceListObject -allUsersPSResources $allUsersPSResources -currentUserPSResources $currentUserPSResources
+            $populatingParams = @{
+                currentUserPSResources = GetAllPsResourcesInScope -Scope CurrentUser
+                allUsersPSResources    = GetAllPsResourcesInScope -Scope AllUsers
+            }
+
+            PopulatePSResourceListObject @populatingParams
         }
         default {
             Write-Trace -level error -message "Unknown ResourceType: $ResourceType"
@@ -747,6 +847,22 @@ function DeleteOperation {
     }
 }
 
+function GetAllPsResourcesInScope {
+    param(
+        [Scope]$Scope
+    )
+
+    try {
+        Get-PSResource -Scope $Scope -ErrorAction Stop
+    } catch [Microsoft.PowerShell.PSResourceGet.UtilClasses.ResourceNotFoundException] {
+        # Everything is fine, there's just no installed resources
+        @()
+    } catch {
+        Write-Trace -level error -message "Failed to get PSResources for '$Scope' scope: $_"
+        @()
+    }
+}
+
 function PopulatePSResourceListObjectByRepository {
     param (
         $resourcesExist,
@@ -794,24 +910,32 @@ function PopulatePSResourceListObject {
 
     $allPSResources = @()
 
-    $allPSResources += $allUsersPSResources | ForEach-Object {
-        return [PSResource]::new(
-            $_.Name,
-            $_.Version,
-            [Scope]"AllUsers",
-            $_.Repository,
-            $_.PreRelease ? $true : $false
-        )
+    if ($allUsersPSResources.count -gt 1) {
+        $allPSResources += $allUsersPSResources | ForEach-Object {
+            return [PSResource]::new(
+                $_.Name,
+                $_.Version,
+                [Scope]"AllUsers",
+                $_.Repository,
+                $_.PreRelease ? $true : $false
+            )
+        }
+    } else {
+        Write-Trace -level info "No PSResources found for AllUsers scope."
     }
 
-    $allPSResources += $currentUserPSResources | ForEach-Object {
-        return [PSResource]::new(
-            $_.Name,
-            $_.Version,
-            [Scope]"CurrentUser",
-            $_.Repository,
-            $_.PreRelease ? $true : $false
-        )
+    if ($currentUserPSResources.count -gt 1) {
+        $allPSResources += $currentUserPSResources | ForEach-Object {
+            return [PSResource]::new(
+                $_.Name,
+                $_.Version,
+                [Scope]"CurrentUser",
+                $_.Repository,
+                $_.PreRelease ? $true : $false
+            )
+        }
+    } else {
+        Write-Trace -level info "No PSResources found for CurrentUser scope."
     }
 
     $repoGrps = $allPSResources | Group-Object -Property repositoryName

src/dsc/psresourcelist.dsc.resource.json

@@ -92,7 +92,7 @@
         "repositoryName": {
           "title": "Repository Name",
           "description": "The name of the repository from where the resources are acquired.",
-          "type": ["string", "null"]
+          "type": "string"
         },
         "trustedRepository": {
           "title": "Trusted Repository",
@@ -115,7 +115,7 @@
       },
       "$defs": {
         "Scope": {
-          "type": ["string", "null"],
+          "type": "string",
           "title": "Scope",
           "description": "Scope of the resource installation.",
           "enum": [
@@ -133,12 +133,12 @@
             "name": {
               "title": "Name",
               "description": "The name of the resource.",
-              "type": ["string", "null"]
+              "type": "string"
             },
             "version": {
               "title": "Version",
               "description": "The version range of the resource.",
-              "type": ["string", "null"]
+              "type": "string"
             },
             "scope": {
               "title": "Scope",
@@ -148,7 +148,7 @@
             "repositoryName": {
               "title": "Repository Name",
               "description": "The name of the repository from where the resource is acquired.",
-              "type": ["string", "null"]
+              "type": "string"
             },
             "preRelease": {
               "title": "Pre-Release version",

src/dsc/repository.dsc.resource.json

@@ -74,23 +74,18 @@
             "description": "A PowerShell Resource repository from where to acquire the resources.",
             "type": "object",
             "additionalProperties": false,
+            "required": ["name"],
             "allOf": [
                 {
                     "if": {
                         "properties": {
                             "_exist": {
-                                "const": false
+                                "const": true
                             }
                         }
                     },
                     "then": {
                         "required": [
-                            "name"
-                        ]
-                    },
-                    "else": {
-                        "required": [
-                            "name",
                             "uri"
                         ]
                     }
@@ -105,7 +100,7 @@
                 "uri": {
                     "title": "URI",
                     "description": "The URI of the repository.",
-                    "type": ["string", "null"],
+                    "type": "string",
                     "format": "uri"
                 },
                 "trusted": {