Fix bug with custom types and deployments whatif (#24140)

* Fix bug with custom types and whatif

* Update changelog

Author: anthony-c-martin

src/Resources/ResourceManager/Json/PSJsonSerializer.cs

@@ -94,7 +94,7 @@ private static object ProcessValue(object value, int currentDepth, SerializeCont
 
             if (value is JObject jObject)
             {
-                return jObject.ToObject<Dictionary<object, object>>();
+                return jObject.Properties().ToDictionary(x => x.Name, x => x.Value);
             }
 
             Type type = value.GetType();

src/Resources/Resources.Test/Resources/DeploymentWhatIfTests/WhatIfWithUserDefinedTypes/main.bicep

@@ -0,0 +1,4 @@
+type managementGroupNameType = string
+
+@description('The ID (not the display name) of the Management Group. Used only when it is management group deployment.')
+param managementGroupName managementGroupNameType = ''

src/Resources/Resources.Test/ScenarioTests/DeploymentWhatIfTests.cs

@@ -66,6 +66,11 @@ public void RGLevelWhatIf_SetExcludeChangeType_HidesResourceChanges()
             TestRunner.RunTestScript("Test-WhatIfExcludeChangeTypesAtResourceGroupScope");
         }
 
+        [Fact]
+        [Trait(Category.AcceptanceType, Category.CheckIn)]
+        public void Test_WhatIfWithUserDefinedTypes()
+            => TestRunner.RunTestScript("Test-WhatIfWithUserDefinedTypes");
+
         [Fact]
         [Trait(Category.AcceptanceType, Category.CheckIn)]
         public void SubLevelWhatIf_BlankTemplate_ReturnsNoChange()

src/Resources/Resources.Test/ScenarioTests/DeploymentWhatIfTests.ps1

@@ -274,6 +274,39 @@ function Test-WhatIfExcludeChangeTypesAtResourceGroupScope
 	}
 }
 
+
+
+<#
+.SYNOPSIS
+Tests what-if with user-defined types (https://github.com/Azure/bicep/issues/13245).
+#>
+function Test-WhatIfWithUserDefinedTypes
+{
+	try
+	{
+		# Arrange.
+		$deploymentName = Get-ResourceName
+		$location = "westus"
+		$resourceGroupName = Get-ResourceGroupName
+
+		New-AzResourceGroup -Name $resourceGroupName -Location $location
+
+		# Act.
+		$result = Get-AzResourceGroupDeploymentWhatIfResult `
+			-ResourceGroupName $resourceGroupName `
+			-Name $deploymentName `
+			-TemplateFile "Resources/DeploymentWhatIfTests/WhatIfWithUserDefinedTypes/main.bicep"
+
+		# Assert.
+		Assert-AreEqual "Succeeded" $result.Status
+	}
+	finally
+	{
+		# Cleanup.
+		Clean-ResourceGroup $resourceGroupName
+	}
+}
+
 <#
 .SYNOPSIS
 Tests subscription level deployment what-if with empty template.

src/Resources/Resources.Test/SessionRecords/Microsoft.Azure.Commands.Resources.Test.ScenarioTests.DeploymentWhatIfTests/Test_WhatIfWithUserDefinedTypes.json

@@ -20,6 +20,7 @@
 
 ## Upcoming Release
 * Added `AuxTenant` parameter in `New-AzResourceGroupDeployment`to support cross-tenant deployment.
+* Fixed bug with custom types and deployments whatif. [#13245]
 
 ## Version 6.15.1
 * Fixed deadlock in Bicep CLI execution. [#24133]