Make nullable parameters optional (#23686)

Author: anthony-c-martin

src/Resources/ResourceManager/SdkModels/Deployments/TemplateFileTypeDefinition.cs

@@ -22,6 +22,9 @@ public class TemplateFileTypeDefinition
         [JsonProperty("type")]
         public string Type { get; set; }
 
+        [JsonProperty("nullable")]
+        public bool? Nullable { get; set; }
+
         [JsonProperty("allowedValues")]
         public List<object> AllowedValues { get; set; }
 

src/Resources/ResourceManager/Utilities/TemplateUtility.cs

@@ -311,7 +311,14 @@ private static TemplateFileTypeDefinition ResolveParameterType(TemplateFileParam
                     throw new InvalidOperationException($"Invalid $ref {current.Ref}.");
                 }
 
-                current = ResolveTypeFromPath(current.Ref, segments.Skip(2), definitions);
+                var resolved = ResolveTypeFromPath(current.Ref, segments.Skip(2), definitions);
+                // it's possible to override some of these properties: the highest-level non-null value wins
+                resolved.Nullable = current.Nullable ?? resolved.Nullable;
+                resolved.MinLength = current.MinLength ?? resolved.MinLength;
+                resolved.MaxLength = current.MaxLength ?? resolved.MaxLength;
+                resolved.AllowedValues = current.AllowedValues ?? resolved.AllowedValues;
+
+                current = resolved;
             }
 
             return current;
@@ -321,28 +328,29 @@ internal static RuntimeDefinedParameter ConstructDynamicParameter(string[] stati
         {
             const string duplicatedParameterSuffix = "FromTemplate";
             var name = parameterKvp.Key;
-            var parameter = ResolveParameterType(parameterKvp.Value, definitions);
-            var defaultValue = parameterKvp.Value.DefaultValue;
+            var paramDefinition = parameterKvp.Value;
+            var paramType = ResolveParameterType(paramDefinition, definitions);
+            var isRequired = paramDefinition.DefaultValue is null && paramType.Nullable != true;
 
             RuntimeDefinedParameter runtimeParameter = new RuntimeDefinedParameter()
             {
                 // For duplicated template parameter names, add a suffix FromTemplate to distinguish them from the cmdlet parameter.
                 Name = staticParameters.Contains(name, StringComparer.OrdinalIgnoreCase) ? name + duplicatedParameterSuffix : name,
-                ParameterType = GetParameterType(parameter.Type),
-                Value = defaultValue
+                ParameterType = GetParameterType(paramType.Type),
+                Value = paramDefinition.DefaultValue
             };
             runtimeParameter.Attributes.Add(new ParameterAttribute()
             {
-                Mandatory = defaultValue == null ? true : false,
+                Mandatory = isRequired,
                 ValueFromPipelineByPropertyName = true,
                 // Rely on the HelpMessage property to detect the original name for the dynamic parameter.
                 HelpMessage = name
             });
 
-            if (!string.IsNullOrEmpty(parameter.MinLength) &&
-                !string.IsNullOrEmpty(parameter.MaxLength))
+            if (!string.IsNullOrEmpty(paramType.MinLength) &&
+                !string.IsNullOrEmpty(paramType.MaxLength))
             {
-                runtimeParameter.Attributes.Add(new ValidateLengthAttribute(int.Parse(parameter.MinLength), int.Parse(parameter.MaxLength)));
+                runtimeParameter.Attributes.Add(new ValidateLengthAttribute(int.Parse(paramType.MinLength), int.Parse(paramType.MaxLength)));
             }
 
             return runtimeParameter;

src/Resources/Resources.Test/Resources.Test.csproj

@@ -31,7 +31,7 @@
   </ItemGroup>
 
   <ItemGroup>
-    <None Update="Resources\*.json" CopyToOutputDirectory="PreserveNewest" />
+    <None Update="Resources/**/*.*" CopyToOutputDirectory="PreserveNewest" />
     <None Update="*.json" CopyToOutputDirectory="PreserveNewest" />
     <None Update="*.bicep" CopyToOutputDirectory="PreserveNewest" />
 	<None Update="*.bicepparam" CopyToOutputDirectory="PreserveNewest" />

src/Resources/Resources.Test/Resources/DeploymentTests/NullableParametersAreNotRequired/main.bicep

@@ -0,0 +1,22 @@
+// sample from https://github.com/Azure/bicep/issues/12538
+targetScope = 'subscription'
+param yourName string?
+
+output greeting string = !empty(yourName)
+  ? 'Hello, ${yourName}. Nice to meet you!'
+  : 'Hey, nice to meet you!'
+
+// verify this also works with nullable custom types
+param optionalCustomType customType?
+type customType = {
+  age: int
+}
+
+param requiredNullableCustomType nullableCustomType
+type nullableCustomType = {
+  age: int
+}?
+
+type customTypeWithRequired = customType!
+
+param optionalRequiredCustomType customTypeWithRequired?

src/Resources/Resources.Test/ScenarioTests/DeploymentTests.cs

@@ -202,6 +202,11 @@ public void TestNewDeploymentFromBicepFileAndBicepparamFile()
             TestRunner.RunTestScript("Test-NewDeploymentFromBicepFileAndBicepparamFile");
         }
 
+        [Fact]
+        [Trait(Category.AcceptanceType, Category.CheckIn)]
+        public void TestNullableParametersAreNotRequired()
+            => TestRunner.RunTestScript("Test-NullableParametersAreNotRequired");
+
         [Fact]
         [Trait(Category.AcceptanceType, Category.CheckIn)]
         public void TestNewDeploymentFromBicepparamFileOnly()

src/Resources/Resources.Test/ScenarioTests/DeploymentTests.ps1

@@ -897,7 +897,31 @@ function Test-NewDeploymentFromBicepFileAndBicepparamFile
     }
 }
 
+<#
+.SYNOPSIS
+Verifies that nullable parameters are not required to be passed
+#>
+function Test-NullableParametersAreNotRequired
+{
+    # Setup
+    $rname = Get-ResourceName
+    $location = "West US 2"
+    $subId = (Get-AzContext).Subscription.SubscriptionId
 
+    try
+    {
+        #Create deployment
+        $deployment = New-AzSubscriptionDeployment -Name $rname -Location $location -TemplateFile "Resources/DeploymentTests/NullableParametersAreNotRequired/main.bicep"
+
+        # Assert
+        Assert-AreEqual Succeeded $deployment.ProvisioningState
+    }
+    finally
+    {
+        # Cleanup
+        Clean-DeploymentAtSubscription $deployment
+    }
+}
 
 <#
 .SYNOPSIS