Update module version to 1.1.0 and enhance Merge-DSCConfigurationData function to prevent modifications to sealed parameters

Reviewed-on: #3

.sample/Deployment.psd1

@@ -0,0 +1,111 @@
+@{
+    Templates = @(
+        @{
+            TemplateName = "HZD Template"
+            TemplatePath = "./Configurations/HZD.psd1"
+        },
+        @{
+            TemplateName = "SQL Server Template"
+            TemplatePath = "./Configurations/Services/Template-SQLServer.psd1"
+        },
+        @{
+            TemplateName = "Umgebungs Template"
+            TemplatePath = "./Configurations/Umgebungen/Template-Test.psd1"
+        }
+    )
+    
+    AllNodes = @(
+        @{
+            NodeName = "JURZMAZSSQL901"
+        }       
+    )
+
+    NonNodeData =@{
+        Services = @{
+            SQLServer = @{
+                Instances = @(
+                    @{ 
+                        Name = 'MSSQLSERVER'
+                        
+                        ServiceAccounts = @{
+                            SQLEngineAccount = @{
+                                ServiceAccountName = "gmsaE2Af901"
+                                AccountType = "Group"
+                                Path = "OU=DBA,OU=Dienste_Verfahren,OU=Administration,DC=justiz,DC=hessen,DC=de"
+                                ManagedPasswordPrincipals = @(
+                                    @{
+                                        GroupName = "sicE2AfE2ADB901"
+                                        Path = "OU=DBA,OU=Dienste_Verfahren,OU=Administration,DC=justiz,DC=hessen,DC=de"
+                                    }
+                                )
+                            }
+                            SQLAgentAccount = @{
+                                ServiceAccountName = "gmsaE2Aa901"
+                                AccountType = "Group"
+                                Path = "OU=DBA,OU=Dienste_Verfahren,OU=Administration,DC=justiz,DC=hessen,DC=de"
+                                ManagedPasswordPrincipals = @(
+                                    @{
+                                        GroupName = "sicE2AfE2ADB901"
+                                        Path = "OU=DBA,OU=Dienste_Verfahren,OU=Administration,DC=justiz,DC=hessen,DC=de"
+                                    }
+                                )
+                            }
+                        }
+                        AlwaysOn = @{
+                           StartIndex = "B"
+                            AlwaysOnGroups = @(
+                                @{
+                                    Name = "TestAG"
+                                    FailoverMode ="Automatic"
+                                    SeedingMode = "Automatic"
+                                    Listener = @{
+                                        Provision = $true
+                                        IpAddress = "'10.96.x.x/255.255.255.0','10.96.x.x/255.255.255.0'"
+                                        Port = 1433
+                                    }
+                                                                       
+                                }                                
+                            )
+                        }
+
+                        ConfigurationOptions= @()
+
+                        AdditionalScripts = @()
+                    },
+                    @{ 
+                        Name = 'MSSQLSERVERTEST'
+                        
+                        ServiceAccounts = @{
+                            SQLEngineAccount = @{
+                                ServiceAccountName = "gmsaE2Af901"
+                                AccountType = "Group"
+                                Path = "OU=DBA,OU=Dienste_Verfahren,OU=Administration,DC=justiz,DC=hessen,DC=de"
+                                ManagedPasswordPrincipals = @(
+                                    @{
+                                        GroupName = "sicE2AfE2ADB901"
+                                        Path = "OU=DBA,OU=Dienste_Verfahren,OU=Administration,DC=justiz,DC=hessen,DC=de"
+                                    }
+                                )
+                            }
+                            SQLAgentAccount = @{
+                                ServiceAccountName = "gmsaE2Aa901"
+                                AccountType = "Group"
+                                Path = "OU=DBA,OU=Dienste_Verfahren,OU=Administration,DC=justiz,DC=hessen,DC=de"
+                                ManagedPasswordPrincipals = @(
+                                    @{
+                                        GroupName = "sicE2AfE2ADB901"
+                                        Path = "OU=DBA,OU=Dienste_Verfahren,OU=Administration,DC=justiz,DC=hessen,DC=de"
+                                    }
+                                )
+                            }
+                        }
+
+                        ConfigurationOptions= @()
+
+                        AdditionalScripts = @()
+                    }
+                )
+            }
+        }
+    }
+}

.sample/Template.psd1

@@ -0,0 +1,157 @@
+@{
+    NonNodeData =@{
+        Services = @{
+            SQLServer = @{
+                General = @{
+                    Version = ""
+                    Release = "2022"
+                    SourcePath = "\\JURZMAZSFIL02.justiz.hessen.de\DbaDSCSources\Binaries"
+                    DestinationPath = "C:\HZD\SQL_Install"
+                }
+                Basic = @{
+                    Registry = @(
+                        @{
+                            Key = "HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Lsa"
+                            ValueName = "DisableLoopbackCheck"
+                            ValueData = 1
+                            ValueType = "Dword"
+                        },
+                        @{
+                            Ensure      = "Present"
+                            Key         = "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\MSSQL16.MSSQLSERVER\SQLServerAgent"
+                            ValueName   = "MsxEncryptChannelOptions"
+                            ValueData   = 1
+	                        ValueType   = "Dword"
+                        }
+
+                        @{
+                            Ensure      = 'Present'
+                            Key         = 'HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\MSSQL16.MSSQLSERVER\SQLServerAgent'
+                            ValueName   = 'ErrorLogFile'
+                            ValueData   = 'D:\MSSQL16.MSSQLSERVER\MSSQL\Log\SQLAGENT.OUT'
+                            ValueType   = 'String'
+                        },
+                        @{
+                            Ensure      = 'Present'
+                            Key         = 'HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Microsoft SQL Server\MSSQL16.MSSQLSERVER\SQLServerAgent'
+                            ValueName   = 'WorkingDirectory'
+                            ValueData   = 'D:\MSSQL16.MSSQLSERVER\MSSQL\JOBS'
+                            ValueType   = 'String'
+                        }
+                    )
+                    WindowsFeatures = @(
+                        @{
+                            Name = "RSAT-AD-PowerShell"
+                        }
+                    )
+                    Modules = @(
+                        @{
+                            Name = "SQLServer"
+                            AllowClobber = $true
+                        }
+                    )
+                }
+                Instances = @(
+                    @{ 
+                        Name = '*'
+                        Features = 'SQLENGINE,FULLTEXT'
+                        SQLSysAdminAccounts = 'sicDBServer_ServerAdmins'
+                        Directories = @{
+                            InstallSharedDir = 'D:\Microsoft SQL Server'
+                            InstallSharedWOWDir = 'D:\Microsoft SQL Server (x86)'
+                            InstanceDir = 'D:\Microsoft SQL Server'
+                            InstallSQLDataDir = 'D:'
+                            SQLSysAdminAccounts = 'sicDBServer_ServerAdmins'
+                            SQLBackupDir = '\\JURZMAZSFIL02.justiz.hessen.de\DbaDSCSources\Backups'
+                            SQLUserDBDir = ''
+                            SQLUserDBLogDir = ''
+                            SQLTempDBDir = ''
+                            SQLTempDBLogDir = ''
+                        }
+
+                        Drives = @{
+                        }
+
+                        MountPoints = @{
+                        }
+
+                        Memory = @{
+                            UseDynamic = $true
+                            minValue = 1024
+                            maxValue = 8192
+                        }
+
+                        ServiceAccounts = @{
+                        }
+                        
+                        AlwaysOn = @{
+                        }
+
+                        ConfigurationOptions= @(
+                            @{
+                                OptionName = 'show advanced options'
+                                OptionValue = '1'
+                            },
+                            @{
+                                OptionName = 'cost threshold for parallelism'
+                                OptionValue = '50'
+                            },
+                            @{
+                                OptionName = 'blocked process threshold (s)'
+                                OptionValue = '30'
+                            },
+                            @{
+                                OptionName = 'backup compression default'
+                                OptionValue = '1'
+                            }
+                        
+                        )
+
+                        AdditionalScripts = @(
+
+                            @{
+                                ScriptName = 'AdminDB'
+                                ScriptPath = '\\JURZMAZSFIL02.justiz.hessen.de\DbaDSCSources\SQL_Scripts\AdminDB'
+                                DependsOn = '[SqlSetup]Instance-MSSQLSERVER'
+                            },
+
+                            @{
+                                ScriptName = 'RenameSA'
+                                ScriptPath = '\\JURZMAZSFIL02.justiz.hessen.de\DbaDSCSources\SQL_Scripts\RenameSA'
+                                DependsOn = '[SqlScript]AdminDB'
+                            
+                            },
+                            @{
+                                ScriptName = 'Maintenance_Solution'
+                                ScriptPath = '\\JURZMAZSFIL02.justiz.hessen.de\DbaDSCSources\SQL_Scripts\Maintenance_Solutions'
+                                DependsOn = '[SqlScript]RenameSA'
+                            },
+
+                            @{
+                                ScriptName = 'WhoIsActive'
+                                ScriptPath = '\\JURZMAZSFIL02.justiz.hessen.de\DbaDSCSources\SQL_Scripts\WhoIsActive_Monitoring'
+                                DependsOn = '[SqlScript]Maintenance_Solution'
+                            },
+
+
+                            @{
+                                ScriptName = 'Alerts'
+                                ScriptPath = '\\JURZMAZSFIL02.justiz.hessen.de\DbaDSCSources\SQL_Scripts\Alerts_Email'
+                                DependsOn = '[SqlScript]WhoIsActive'
+                            },
+
+
+                            @{
+                                ScriptName = 'TempDB'
+                                ScriptPath = '\\JURZMAZSFIL02.justiz.hessen.de\DbaDSCSources\SQL_Scripts\TempDB_Size'
+                                DependsOn = '[SqlScript]Alerts'
+                            
+                            }
+                            
+                        )
+                    }
+                )
+            }
+        }
+    }
+}

.tests/Merge-DSCConfigurationData.Tests.ps1

@@ -0,0 +1,132 @@
+$script:ModuleRoot = Split-Path -Parent $PSScriptRoot
+$script:SampleRoot = Join-Path -Path $script:ModuleRoot -ChildPath ".sample"
+
+Import-Module (Join-Path -Path $script:ModuleRoot -ChildPath "Merge-DSCConfigurationData.psd1") -Force
+
+Describe "Merge-DSCConfigurationData" {
+    It "merges wildcard instance templates into all deployment instances" {
+        $Template = Import-PowerShellDataFile (Join-Path -Path $script:SampleRoot -ChildPath "Template.psd1")
+        $Deployment = Import-PowerShellDataFile (Join-Path -Path $script:SampleRoot -ChildPath "Deployment.psd1")
+
+        $Result = Merge-DSCConfigurationData -Template $Template -Deployment $Deployment
+        $Instances = @($Result.NonNodeData.Services.SQLServer.Instances)
+
+        $Instances.Count | Should Be 2
+        ($Instances.Name -contains "*") | Should Be $false
+
+        foreach($Name in @("MSSQLSERVER", "MSSQLSERVERTEST")){
+            $Instance = $Instances | Where-Object { $_.Name -eq $Name }
+
+            $Instance | Should Not BeNullOrEmpty
+            $Instance.Features | Should Be "SQLENGINE,FULLTEXT"
+            $Instance.ConfigurationOptions.Count | Should Be 4
+            $Instance.AdditionalScripts.Count | Should Be 6
+            $Instance.Memory | Should Not BeNullOrEmpty
+            $Instance.Directories | Should Not BeNullOrEmpty
+        }
+    }
+
+    It "does not merge an exact instance template into another instance name" {
+        $Template = @{
+            NonNodeData = @{
+                Services = @{
+                    SQLServer = @{
+                        Instances = @(
+                            @{
+                                Name = "MSSQLSERVER"
+                                Marker = "exact-only"
+                            }
+                        )
+                    }
+                }
+            }
+        }
+
+        $Deployment = @{
+            NonNodeData = @{
+                Services = @{
+                    SQLServer = @{
+                        Instances = @(
+                            @{ Name = "MSSQLSERVER" },
+                            @{ Name = "MSSQLSERVERTEST" }
+                        )
+                    }
+                }
+            }
+        }
+
+        $Result = Merge-DSCConfigurationData -Template $Template -Deployment $Deployment
+        $Instances = @($Result.NonNodeData.Services.SQLServer.Instances)
+
+        ($Instances | Where-Object { $_.Name -eq "MSSQLSERVER" }).Marker | Should Be "exact-only"
+        ($Instances | Where-Object { $_.Name -eq "MSSQLSERVERTEST" }).Marker | Should BeNullOrEmpty
+    }
+
+    It "uses the name-key fallback for unknown arrays" {
+        $Template = @{
+            Databases = @(
+                @{
+                    DatabaseName = "AppDb"
+                    RecoveryModel = "Full"
+                }
+            )
+        }
+
+        $Deployment = @{
+            Databases = @(
+                @{
+                    DatabaseName = "AppDb"
+                    Owner = "dbo"
+                },
+                @{
+                    DatabaseName = "LogDb"
+                    Owner = "dbo"
+                }
+            )
+        }
+
+        $Result = Merge-DSCConfigurationData -Template $Template -Deployment $Deployment
+        $Databases = @($Result.Databases)
+
+        ($Databases | Where-Object { $_.DatabaseName -eq "AppDb" }).RecoveryModel | Should Be "Full"
+        ($Databases | Where-Object { $_.DatabaseName -eq "LogDb" }).RecoveryModel | Should BeNullOrEmpty
+    }
+
+    It "uses Key and ValueName together for registry array merges" {
+        $Template = @{
+            Basic = @{
+                Registry = @(
+                    @{
+                        Key = "K1"
+                        ValueName = "Enabled"
+                        Default = "Template-K1"
+                    },
+                    @{
+                        Key = "K2"
+                        ValueName = "Enabled"
+                        Default = "Template-K2"
+                    }
+                )
+            }
+        }
+
+        $Deployment = @{
+            Basic = @{
+                Registry = @(
+                    @{
+                        Key = "K1"
+                        ValueName = "Enabled"
+                        ValueData = "Deployment-K1"
+                    }
+                )
+            }
+        }
+
+        $Result = Merge-DSCConfigurationData -Template $Template -Deployment $Deployment
+        $Registry = @($Result.Basic.Registry)
+
+        ($Registry | Where-Object { $_.Key -eq "K1" }).Default | Should Be "Template-K1"
+        ($Registry | Where-Object { $_.Key -eq "K1" }).ValueData | Should Be "Deployment-K1"
+        ($Registry | Where-Object { $_.Key -eq "K2" }).Default | Should Be "Template-K2"
+    }
+}

Merge-DSCConfigurationData.psd1

@@ -1,6 +1,6 @@
 @{
     RootModule = "Merge-DSCConfigurationData.psm1"
-    ModuleVersion = "1.0.1"
+    ModuleVersion = "1.1.0"
     GUID = "c1c7e70d-9049-4eaa-a3c9-44a424c35ef5"
     Author = "Torsten Brendgen"
     Copyright = "(c) Torsten Brendgen. All rights reserved."
@@ -9,7 +9,8 @@
     FunctionsToExport = @(
         "Merge-DSCConfigurationData",
         "Export-PowerShellDataFile",
-        "New-DSCConfigurationDataDeployment"
+        "New-DSCConfigurationDataDeployment",
+        "Test-DSCConfigurationDataDeployment"
     )
     CmdletsToExport = @()
     VariablesToExport = @()

Merge-DSCConfigurationData.psm1

@@ -11,5 +11,6 @@ foreach($File in @($Private + $Public)){
 Export-ModuleMember -Function @(
     "Merge-DSCConfigurationData",
     "Export-PowerShellDataFile",
-    "New-DSCConfigurationDataDeployment"
+    "New-DSCConfigurationDataDeployment",
+    "Test-DSCConfigurationDataDeployment"
 )

Private/Get-ConfigurationDataSourceFileInfo.ps1

@@ -0,0 +1,34 @@
+function Get-ConfigurationDataSourceFileInfo {
+    [CmdletBinding()]
+    Param(
+        [Parameter(Mandatory=$true)]
+        [string]
+        $Path,
+
+        [Parameter(Mandatory=$true)]
+        [string]
+        $BasePath,
+
+        [Parameter(Mandatory=$false)]
+        [switch]
+        $UseRelativePath
+    )
+
+    $ResolvedPath = Resolve-ConfigurationDataTemplatePath -Path $Path -BasePath $BasePath
+    $Item = Get-Item -LiteralPath $ResolvedPath
+    $Hash = Get-FileHash -LiteralPath $ResolvedPath -Algorithm SHA256
+
+    $DisplayPath = if($UseRelativePath){
+        ConvertTo-ConfigurationDataRelativePath -Path $ResolvedPath -BasePath $BasePath
+    }else{
+        $ResolvedPath
+    }
+
+    [ordered]@{
+        Path = $DisplayPath
+        Hash = $Hash.Hash
+        Algorithm = $Hash.Algorithm
+        Size = $Item.Length
+        LastWriteTimeUtc = $Item.LastWriteTimeUtc.ToString("o")
+    }
+}

Private/Resolve-ConfigurationDataSourcePath.ps1

@@ -0,0 +1,19 @@
+function Resolve-ConfigurationDataSourcePath {
+    [CmdletBinding()]
+    Param(
+        [Parameter(Mandatory=$true)]
+        [string]
+        $Path,
+
+        [Parameter(Mandatory=$true)]
+        [string]
+        $DeploymentPath
+    )
+
+    $BasePath = Split-Path -Path (Repair-ConfigurationDataPathEncoding -Path $DeploymentPath) -Parent
+    if([string]::IsNullOrWhiteSpace($BasePath)){
+        $BasePath = (Get-Location).Path
+    }
+
+    return Resolve-ConfigurationDataTemplatePath -Path $Path -BasePath $BasePath
+}

Private/Test-ConfigurationDataNodeSealed.ps1

@@ -0,0 +1,14 @@
+function Test-ConfigurationDataNodeSealed {
+    [CmdletBinding()]
+    Param(
+        [Parameter(Mandatory=$true)]
+        [System.Collections.IDictionary]
+        $Node
+    )
+
+    if(-not (Test-ConfigurationDataDictionaryKey -Dictionary $Node -Key "Sealed")){
+        return $false
+    }
+
+    return [System.Management.Automation.LanguagePrimitives]::ConvertTo($Node["Sealed"], [bool])
+}

Public/Merge-DSCConfigurationData.ps1

@@ -20,7 +20,11 @@ function Merge-DSCConfigurationData {
 
         [Parameter(Mandatory=$false, ParameterSetName="Path")]
         [switch]
-        $PassThru
+        $PassThru,
+
+        [Parameter(Mandatory=$false, ParameterSetName="Data")]
+        [string]
+        $MergePath = '$'
     )
 
     begin {
@@ -37,6 +41,10 @@ function Merge-DSCConfigurationData {
             $Output = $Deployment
         }
 
+        if((Test-ConfigurationDataNodeSealed -Node $Template) -and $Deployment.Count -gt 0){
+            throw "Configuration data path [$MergePath] is sealed and cannot be modified."
+        }
+
         foreach($Property in $Template.GetEnumerator()){
             if($Property.Name -eq "Metadata"){
                 Write-Verbose "Skipping metadata block during configuration data merge"
@@ -47,7 +55,7 @@ function Merge-DSCConfigurationData {
                 Write-Verbose "Key [$($Property.Name)] is a Dictionary"
                 if(Test-ConfigurationDataDictionaryKey -Dictionary $Deployment -Key $Property.Name){
                     Write-Verbose "Key [$($Property.Name)] is present in Deployment Data"
-                    $Output[$Property.Name] = Merge-DSCConfigurationData -Template $Template[$Property.Name] -Deployment $Deployment[$Property.Name] -Output $Output[$Property.Name]
+                    $Output[$Property.Name] = Merge-DSCConfigurationData -Template $Template[$Property.Name] -Deployment $Deployment[$Property.Name] -Output $Output[$Property.Name] -MergePath "$MergePath.$($Property.Name)"
                 }else{
                     Write-Verbose "Key [$($Property.Name)] is not present in Deployment Data"
                     $Output.Add($Property.Name,(Copy-ConfigurationDataValue -Value $Template[$Property.Name]))
@@ -89,7 +97,7 @@ function Merge-DSCConfigurationData {
                         if($MatchingDeploymentItems.Count -gt 0){
                             foreach($DeploymentItem in $MatchingDeploymentItems){
                                 $OutputItem = @($Output[$Property.Name] | Where-Object { Test-ConfigurationDataItemKeyMatch -Left $_ -Right $DeploymentItem -KeyNames $SearchKeyNames })[0]
-                                Merge-DSCConfigurationData -Template $TemplateItem.Value -Deployment $DeploymentItem -Output $OutputItem | Out-Null
+                                Merge-DSCConfigurationData -Template $TemplateItem.Value -Deployment $DeploymentItem -Output $OutputItem -MergePath "$MergePath.$($Property.Name)[$(Format-ConfigurationDataMergeKey -Item $DeploymentItem -KeyNames $SearchKeyNames)]" | Out-Null
                             }
                         }else{
                             if($TemplateItem.IsWildcard){

Public/New-DSCConfigurationDataDeployment.ps1

@@ -91,11 +91,7 @@ function New-DSCConfigurationDataDeployment {
     })
 
     $SourceFiles = @($MergeResult.Files | ForEach-Object {
-        if($UseRelativePaths){
-            ConvertTo-ConfigurationDataRelativePath -Path $_ -BasePath $OutputDirectory
-        }else{
-            $_
-        }
+        Get-ConfigurationDataSourceFileInfo -Path $_ -BasePath $OutputDirectory -UseRelativePath:$UseRelativePaths
     })
 
     $ConfigurationData["Metadata"] = [ordered]@{

Public/Test-DSCConfigurationDataDeployment.ps1

@@ -0,0 +1,125 @@
+function Test-DSCConfigurationDataDeployment {
+    [CmdletBinding()]
+    Param(
+        [Parameter(Mandatory=$true)]
+        [string]
+        $Path,
+
+        [Parameter(Mandatory=$false)]
+        [switch]
+        $PassThru
+    )
+
+    $ResolvedPath = Repair-ConfigurationDataPathEncoding -Path $Path
+    $Issues = @()
+
+    if(-not (Test-Path -LiteralPath $ResolvedPath -PathType Leaf)){
+        $Issues += [PSCustomObject]@{
+            Severity = "Error"
+            Code = "DeploymentNotFound"
+            Path = $ResolvedPath
+            Message = "Deployment file was not found."
+        }
+    }else{
+        try {
+            $DeploymentData = Import-PowerShellDataFile -LiteralPath $ResolvedPath
+        }
+        catch {
+            $Issues += [PSCustomObject]@{
+                Severity = "Error"
+                Code = "DeploymentImportFailed"
+                Path = $ResolvedPath
+                Message = $_.Exception.Message
+            }
+        }
+    }
+
+    if($null -ne $DeploymentData){
+        if(-not (Test-ConfigurationDataDictionaryKey -Dictionary $DeploymentData -Key "Metadata")){
+            $Issues += [PSCustomObject]@{ Severity = "Error"; Code = "MetadataMissing"; Path = $ResolvedPath; Message = "Metadata block is missing." }
+        }elseif($DeploymentData.Metadata.TemplateType -ne "Deployment"){
+            $Issues += [PSCustomObject]@{ Severity = "Error"; Code = "InvalidTemplateType"; Path = $ResolvedPath; Message = "Metadata.TemplateType must be [Deployment]." }
+        }
+
+        foreach($Key in @("Parameters", "Variables", "Resources")){
+            if(-not (Test-ConfigurationDataDictionaryKey -Dictionary $DeploymentData -Key $Key)){
+                $Issues += [PSCustomObject]@{ Severity = "Error"; Code = "$Key`Missing"; Path = $ResolvedPath; Message = "Required block [$Key] is missing." }
+            }
+        }
+
+        if((Test-ConfigurationDataDictionaryKey -Dictionary $DeploymentData -Key "Resources") -and
+            (-not (Test-ConfigurationDataDictionaryKey -Dictionary $DeploymentData.Resources -Key "AllNodes"))){
+            $Issues += [PSCustomObject]@{ Severity = "Error"; Code = "AllNodesMissing"; Path = $ResolvedPath; Message = "Resources.AllNodes is missing." }
+        }
+
+        if((Test-ConfigurationDataDictionaryKey -Dictionary $DeploymentData -Key "Resources") -and
+            (Test-ConfigurationDataDictionaryKey -Dictionary $DeploymentData.Resources -Key "AllNodes")){
+            $NodeNames = @{}
+            foreach($Node in @($DeploymentData.Resources.AllNodes)){
+                if(-not (Test-ConfigurationDataDictionaryKey -Dictionary $Node -Key "NodeName") -or [string]::IsNullOrWhiteSpace([string]$Node.NodeName)){
+                    $Issues += [PSCustomObject]@{ Severity = "Error"; Code = "NodeNameMissing"; Path = $ResolvedPath; Message = "An AllNodes item has no NodeName." }
+                    continue
+                }
+
+                $NodeName = [string]$Node.NodeName
+                if($NodeNames.ContainsKey($NodeName)){
+                    $Issues += [PSCustomObject]@{ Severity = "Error"; Code = "DuplicateNodeName"; Path = $ResolvedPath; Message = "Duplicate NodeName [$NodeName]." }
+                }else{
+                    $NodeNames[$NodeName] = $true
+                }
+            }
+        }
+
+        if($DeploymentData.Metadata -is [System.Collections.IDictionary] -and
+            (Test-ConfigurationDataDictionaryKey -Dictionary $DeploymentData.Metadata -Key "Sources") -and
+            $DeploymentData.Metadata.Sources -is [System.Collections.IDictionary] -and
+            (Test-ConfigurationDataDictionaryKey -Dictionary $DeploymentData.Metadata.Sources -Key "Files")){
+            foreach($Source in @($DeploymentData.Metadata.Sources.Files)){
+                $SourcePath = if($Source -is [System.Collections.IDictionary]){ [string]$Source.Path } else { [string]$Source }
+                if([string]::IsNullOrWhiteSpace($SourcePath)){
+                    $Issues += [PSCustomObject]@{ Severity = "Warning"; Code = "SourcePathMissing"; Path = $ResolvedPath; Message = "A source file entry has no path." }
+                    continue
+                }
+
+                try {
+                    $ActualPath = Resolve-ConfigurationDataSourcePath -Path $SourcePath -DeploymentPath $ResolvedPath
+                }
+                catch {
+                    $Issues += [PSCustomObject]@{ Severity = "Warning"; Code = "SourceMissing"; Path = $SourcePath; Message = $_.Exception.Message }
+                    continue
+                }
+
+                if($Source -is [System.Collections.IDictionary] -and (Test-ConfigurationDataDictionaryKey -Dictionary $Source -Key "Hash")){
+                    $Algorithm = [string](Get-ConfigurationDataDictionaryValue -Dictionary $Source -Key "Algorithm" -DefaultValue "SHA256")
+                    $ActualHash = Get-FileHash -LiteralPath $ActualPath -Algorithm $Algorithm
+                    if($ActualHash.Hash -ne [string]$Source.Hash){
+                        $Issues += [PSCustomObject]@{
+                            Severity = "Warning"
+                            Code = "SourceChanged"
+                            Path = $SourcePath
+                            Message = "Source file hash has changed."
+                            ExpectedHash = [string]$Source.Hash
+                            ActualHash = $ActualHash.Hash
+                            Algorithm = $Algorithm
+                        }
+                    }
+                }
+            }
+        }else{
+            $Issues += [PSCustomObject]@{ Severity = "Warning"; Code = "SourceMetadataMissing"; Path = $ResolvedPath; Message = "Metadata.Sources.Files is missing." }
+        }
+    }
+
+    $Result = [PSCustomObject]@{
+        Path = $ResolvedPath
+        IsValid = @($Issues | Where-Object { $_.Severity -eq "Error" }).Count -eq 0
+        IsStale = @($Issues | Where-Object { $_.Code -in @("SourceChanged", "SourceMissing") }).Count -gt 0
+        Issues = $Issues
+    }
+
+    if($PassThru){
+        return $Result
+    }
+
+    return $Result.IsValid -and (-not $Result.IsStale)
+}

Tests/Extends.Tests.ps1

@@ -212,6 +212,8 @@ Describe 'Merge-DSCConfigurationData Extends' {
             Required = $true
         }
     }
+    Variables = @{
+    }
 }
 '@ | Set-Content -Path $DefaultPath -Encoding UTF8
 
@@ -250,6 +252,8 @@ Describe 'Merge-DSCConfigurationData Extends' {
         $DeploymentPath | Should Exist
         $Result.ConfigurationData.Metadata.TemplateType | Should Be 'Deployment'
         $Result.ConfigurationData.Metadata.Sources.Files.Count | Should Be 2
+        $Result.ConfigurationData.Metadata.Sources.Files[0].Hash.Length | Should Be 64
+        $Result.ConfigurationData.Metadata.Sources.Files[0].Algorithm | Should Be 'SHA256'
         $Result.ConfigurationData.Parameters.DomainFQDN.Value | Should Be 'contoso.local'
         $Result.ConfigurationData.Resources.AllNodes[0].NodeName | Should Be 'Node01'
         $Result.ConfigurationData.Resources.AllNodes[0].RunCentralAdministration | Should Be $true
@@ -257,6 +261,10 @@ Describe 'Merge-DSCConfigurationData Extends' {
         $Imported = Import-PowerShellDataFile -Path $DeploymentPath
         $Imported.Metadata.Name | Should Be 'Contoso-Test'
         $Imported.Metadata.Sources.Templates.Count | Should Be 1
+
+        $Validation = Test-DSCConfigurationDataDeployment -Path $DeploymentPath -PassThru
+        $Validation.IsValid | Should Be $true
+        $Validation.IsStale | Should Be $false
     }
 
     It 'exports materialized deployment data as JSON' {
@@ -271,6 +279,8 @@ Describe 'Merge-DSCConfigurationData Extends' {
             Value = 'contoso.local'
         }
     }
+    Variables = @{
+    }
 }
 '@ | Set-Content -Path $DefaultPath -Encoding UTF8
 
@@ -288,4 +298,112 @@ Describe 'Merge-DSCConfigurationData Extends' {
         $Imported.Metadata.TemplateType | Should Be 'Deployment'
         $Imported.Parameters.DomainFQDN.Value | Should Be 'contoso.local'
     }
+
+    It 'detects changed deployment source files by hash' {
+        $DefaultPath = Join-Path -Path $TestDrive -ChildPath 'Default.psd1'
+        $DeploymentPath = Join-Path -Path $TestDrive -ChildPath 'Deployment_123.psd1'
+
+        @'
+@{
+    Parameters = @{
+        DomainFQDN = @{
+            Type = 'string'
+            Value = 'contoso.local'
+        }
+    }
+    Variables = @{
+    }
+}
+'@ | Set-Content -Path $DefaultPath -Encoding UTF8
+
+        New-DSCConfigurationDataDeployment `
+            -Path $DeploymentPath `
+            -Name 'Contoso-Test' `
+            -DeploymentId '123' `
+            -SourceTemplatePath $DefaultPath `
+            -AllNodes @(
+                @{
+                    NodeName = 'Node01'
+                }
+            ) `
+            -Export `
+            -Force
+
+        @'
+@{
+    Parameters = @{
+        DomainFQDN = @{
+            Type = 'string'
+            Value = 'changed.local'
+        }
+    }
+    Variables = @{
+    }
+}
+'@ | Set-Content -Path $DefaultPath -Encoding UTF8
+
+        $Validation = Test-DSCConfigurationDataDeployment -Path $DeploymentPath -PassThru
+        $Validation.IsValid | Should Be $true
+        $Validation.IsStale | Should Be $true
+        @($Validation.Issues | Where-Object { $_.Code -eq 'SourceChanged' }).Count | Should Be 1
+    }
+
+    It 'prevents overriding a sealed parameter definition' {
+        $Template = @{
+            Parameters = @{
+                DomainNetBIOS = @{
+                    Type = 'string'
+                    Value = 'CONTOSO'
+                    Sealed = $true
+                }
+            }
+        }
+
+        $Deployment = @{
+            Parameters = @{
+                DomainNetBIOS = @{
+                    Value = 'OTHER'
+                }
+            }
+        }
+
+        { Merge-DSCConfigurationData -Template $Template -Deployment $Deployment } | Should Throw
+    }
+
+    It 'prevents adding values below a sealed resource tree' {
+        $Template = @{
+            Resources = @{
+                NonNodeData = @{
+                    Services = @{
+                        SharePoint = @{
+                            Farm = @{
+                                ManagedAccounts = @{
+                                    Sealed = $true
+                                    FarmAccount = "[parameters('FarmCredential')]"
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        $Deployment = @{
+            Resources = @{
+                NonNodeData = @{
+                    Services = @{
+                        SharePoint = @{
+                            Farm = @{
+                                ManagedAccounts = @{
+                                    SearchAccount = "[parameters('SearchCredential')]"
+                                }
+                            }
+                        }
+                    }
+                }
+            }
+        }
+
+        { Merge-DSCConfigurationData -Template $Template -Deployment $Deployment } | Should Throw
+    }
 }