Fix config size limit by validating modules in cache

powershell-adapter/Tests/powershellgroup.config.tests.ps1

@@ -33,6 +33,23 @@ Describe 'PowerShell adapter resource tests' {
         $res.results[0].result.actualState.result[0].properties.EnumProp | Should -BeExactly 'Expected'
     }
 
+    It 'Get does not work on config when module does not exist' {
+
+        $yaml = @'
+            $schema: https://raw.githubusercontent.com/PowerShell/DSC/main/schemas/2024/04/config/document.json
+            resources:
+            - name: Working with class-based resources
+              type: Microsoft.DSC/PowerShell
+              properties:
+                resources:
+                - name: Class-resource Info
+                  type: TestClassResourceNotExist/TestClassResourceNotExist
+'@
+        $yaml | dsc -l trace config get -f - 2> "$TestDrive/tracing.txt"
+        $LASTEXITCODE | Should -Be 2
+        "$TestDrive/tracing.txt" | Should -FileContentMatch 'DSC resource TestClassResourceNotExist/TestClassResourceNotExist module not found.'
+    }
+
     It 'Test works on config with class-based resources' {
 
         $r = Get-Content -Raw $pwshConfigPath | dsc config test -f -

powershell-adapter/psDscAdapter/powershell.resource.ps1

@@ -148,11 +148,18 @@ switch ($Operation) {
             exit 1
         }
 
+        # get unique module names from the desiredState input
+        $moduleInput = $desiredState | Select-Object -ExpandProperty Type | Sort-Object -Unique
+
+        # refresh the cache with the modules that are available on the system
         $dscResourceCache = Invoke-DscCacheRefresh -module $dscResourceModules
-        if ($dscResourceCache.count -lt $dscResourceModules.count) {
-            $trace = @{'Debug' = 'ERROR: DSC resource module not found.' } | ConvertTo-Json -Compress
-            $host.ui.WriteErrorLine($trace)
-            exit 1
+
+        # check if all the desired modules are in the cache
+        $moduleInput | ForEach-Object {
+            if ($dscResourceCache.type -notcontains $_) {
+                ('DSC resource {0} module not found.' -f $_) | Write-DscTrace -Operation Error
+                exit 1
+            }
         }
 
         foreach ($ds in $desiredState) {