Add experimental feature to enable runtime values in tags and SKU

docs/experimental-features.md

@@ -42,6 +42,21 @@ Enables the 'resourceInfo' function for simplified code generation.
 
 Enables the type for a parameter or output to be of type resource to make it easier to pass resource references between modules. This feature is only partially implemented. See [Simplifying resource referencing](https://github.com/azure/bicep/issues/2245).
 
+### `runtimeValuesInTagsAndSku`
+
+Allows the use of runtime values (such as this.existingResource()) in `tags` and `sku` properties. By default, these properties are flagged as deploy-time constants, meaning they cannot reference runtime resource properties. Enabling this feature relaxes that restriction. (Note: This feature will not work until the backend service support has been deployed)
+
+```bicep
+resource example 'Microsoft...' = {
+  name: 'example'
+  location: resourceGroup().location
+  sku: {
+    name: this.existingResource().?sku.name ?? 'Standard'
+  }
+  tags: this.existingResource().?tags ?? {}
+}
+```
+
 ### `sourceMapping`
 
 Enables basic source mapping to map an error location returned in the ARM template layer back to the relevant location in the Bicep file.

src/Bicep.Core.UnitTests/Configuration/ConfigurationManagerTests.cs

@@ -114,7 +114,8 @@ public void GetBuiltInConfiguration_NoParameter_ReturnsBuiltInConfigurationWithA
           "localDeploy": false,
           "resourceInfoCodegen": false,
           "userDefinedConstraints": false,
-          "deployCommands": false
+          "deployCommands": false,
+          "runtimeValuesInTagsAndSku": false
         },
         "formatting": {
           "indentKind": "Space",
@@ -199,7 +200,8 @@ public void GetBuiltInConfiguration_DisableAllAnalyzers_ReturnsBuiltInConfigurat
           "resourceInfoCodegen": false,
           "moduleExtensionConfigs": false,
           "userDefinedConstraints": false,
-          "deployCommands": false
+          "deployCommands": false,
+          "runtimeValuesInTagsAndSku": false
         },
         "formatting": {
           "indentKind": "Space",
@@ -306,7 +308,8 @@ public void GetBuiltInConfiguration_DisableAnalyzers_ReturnsBuiltInConfiguration
           "resourceInfoCodegen": false,
           "moduleExtensionConfigs": false,
           "userDefinedConstraints": false,
-          "deployCommands": false
+          "deployCommands": false,
+          "runtimeValuesInTagsAndSku": false
         },
         "formatting": {
           "indentKind": "Space",
@@ -391,7 +394,8 @@ public void GetBuiltInConfiguration_EnableExperimentalFeature_ReturnsBuiltInConf
                 ResourceInfoCodegen: false,
                 ModuleExtensionConfigs: false,
                 UserDefinedConstraints: false,
-                DeployCommands: false);
+                DeployCommands: false,
+                RuntimeValuesInTagsAndSku: false);
 
             configuration.WithExperimentalFeaturesEnabled(experimentalFeaturesEnabled).Should().HaveContents(/*lang=json,strict*/ """
             {
@@ -477,7 +481,8 @@ public void GetBuiltInConfiguration_EnableExperimentalFeature_ReturnsBuiltInConf
                 "resourceInfoCodegen": false,
                 "moduleExtensionConfigs": false,
                 "userDefinedConstraints": false,
-                "deployCommands": false
+                "deployCommands": false,
+                "runtimeValuesInTagsAndSku": false
             },
             "formatting": {
                 "indentKind": "Space",
@@ -832,7 +837,8 @@ public void GetConfiguration_ValidCustomConfiguration_OverridesBuiltInConfigurat
                     "resourceInfoCodegen": false,
                     "moduleExtensionConfigs": false,
                     "userDefinedConstraints": false,
-                    "deployCommands": false
+                    "deployCommands": false,
+                    "runtimeValuesInTagsAndSku": false
                   },
                   "formatting": {
                     "indentKind": "Space",

src/Bicep.Core.UnitTests/Features/FeatureProviderOverrides.cs

@@ -24,7 +24,8 @@ public record FeatureProviderOverrides(
     string? AssemblyVersion = BicepTestConstants.DevAssemblyFileVersion,
     bool? ModuleExtensionConfigsEnabled = default,
     bool? UserDefinedConstraintsEnabled = default,
-    bool? DeployCommandsEnabled = default)
+    bool? DeployCommandsEnabled = default,
+    bool? RuntimeValuesInTagsAndSkuEnabled = default)
 {
     public FeatureProviderOverrides(
         TestContext testContext,
@@ -43,7 +44,8 @@ public FeatureProviderOverrides(
         string? AssemblyVersion = BicepTestConstants.DevAssemblyFileVersion,
         bool? ModuleExtensionConfigsEnabled = default,
         bool? UserDefinedConstraintsEnabled = default,
-        bool? DeployCommandsEnabled = default) : this(
+        bool? DeployCommandsEnabled = default,
+        bool? RuntimeValuesInTagsAndSkuEnabled = default) : this(
             FileHelper.GetCacheRootDirectory(testContext),
             RegistryEnabled,
             OciEnabled,
@@ -60,6 +62,7 @@ public FeatureProviderOverrides(
             AssemblyVersion,
             ModuleExtensionConfigsEnabled,
             UserDefinedConstraintsEnabled,
-            DeployCommandsEnabled)
+            DeployCommandsEnabled,
+            RuntimeValuesInTagsAndSkuEnabled)
     { }
 }

src/Bicep.Core.UnitTests/Features/OverriddenFeatureProvider.cs

@@ -46,4 +46,6 @@ public OverriddenFeatureProvider(IFeatureProvider features, FeatureProviderOverr
     public bool UserDefinedConstraintsEnabled => overrides.UserDefinedConstraintsEnabled ?? features.UserDefinedConstraintsEnabled;
 
     public bool DeployCommandsEnabled => overrides.DeployCommandsEnabled ?? features.DeployCommandsEnabled;
+
+    public bool RuntimeValuesInTagsAndSkuEnabled => overrides.RuntimeValuesInTagsAndSkuEnabled ?? features.RuntimeValuesInTagsAndSkuEnabled;
 }

src/Bicep.Core.UnitTests/Semantics/Namespaces/ThisNamespaceTests.cs

@@ -534,5 +534,152 @@ public void ThisNamespace_ForLoopNamedThis_ShouldSucceed()
                 template.Should().HaveValueAtPath("$.resources[0].name", "[format('testStorage{0}', range(0, 2)[copyIndex()])]");
             }
         }
+
+        [TestMethod]
+        public void ThisNamespace_ExistingResourceInTags_WithFeatureEnabled_ShouldSucceed()
+        {
+            var services = new ServiceBuilder().WithFeatureOverrides(new(TestContext, RuntimeValuesInTagsAndSkuEnabled: true));
+            var result = CompilationHelper.Compile(services, @"
+resource testResource 'Microsoft.Storage/storageAccounts@2021-04-01' = {
+  name: 'testStorage'
+  location: 'westus'
+  sku: {
+    name: 'Standard_LRS'
+  }
+  kind: 'StorageV2'
+  tags: {
+    previousAccessTier: this.existingResource().?properties.accessTier ?? 'unknown'
+  }
+  properties: {
+    allowBlobPublicAccess: this.exists()
+  }
+}
+");
+
+            result.Should().NotHaveAnyDiagnostics();
+
+            using (new AssertionScope())
+            {
+                var template = result.Template;
+
+                template.Should().HaveValueAtPath("$.resources.testResource.tags.previousAccessTier", "[coalesce(tryGet(target('full'), 'properties', 'accessTier'), 'unknown')]");
+                template.Should().HaveValueAtPath("$.resources.testResource.properties.allowBlobPublicAccess", "[not(empty(target('full')))]");
+            }
+        }
+
+        [TestMethod]
+        public void ThisNamespace_ExistingResourceInSku_WithFeatureEnabled_ShouldSucceed()
+        {
+            var services = new ServiceBuilder().WithFeatureOverrides(new(TestContext, RuntimeValuesInTagsAndSkuEnabled: true));
+            var result = CompilationHelper.Compile(services, @"
+resource testResource 'Microsoft.Storage/storageAccounts@2021-04-01' = {
+  name: 'testStorage'
+  location: 'westus'
+  sku: {
+    name: this.existingResource().?sku.name ?? 'Standard_LRS'
+  }
+  kind: 'StorageV2'
+  properties: {
+    allowBlobPublicAccess: this.exists()
+  }
+}
+");
+
+            result.Should().NotHaveAnyDiagnostics();
+
+            using (new AssertionScope())
+            {
+                var template = result.Template;
+
+                template.Should().HaveValueAtPath("$.resources.testResource.sku.name", "[coalesce(tryGet(target('full'), 'sku', 'name'), 'Standard_LRS')]");
+            }
+        }
+
+        [TestMethod]
+        public void ThisNamespace_ExistingResourceInTags_WithFeatureDisabled_ShouldFail()
+        {
+            var services = new ServiceBuilder().WithFeatureOverrides(new(TestContext, RuntimeValuesInTagsAndSkuEnabled: false));
+            var result = CompilationHelper.Compile(services, @"
+resource testResource 'Microsoft.Storage/storageAccounts@2021-04-01' = {
+  name: 'testStorage'
+  location: 'westus'
+  sku: {
+    name: 'Standard_LRS'
+  }
+  kind: 'StorageV2'
+  tags: {
+    previousAccessTier: this.existingResource().?properties.accessTier ?? 'unknown'
+  }
+  properties: {
+    allowBlobPublicAccess: this.exists()
+  }
+}
+");
+
+            result.ExcludingLinterDiagnostics().Should().HaveDiagnostics(new[]
+            {
+                ("BCP120", DiagnosticLevel.Error, "This expression is being used in an assignment to the \"tags\" property of the \"Microsoft.Storage/storageAccounts\" type, which requires a value that can be calculated at the start of the deployment."),
+            });
+        }
+
+        [TestMethod]
+        public void ThisNamespace_ExistingResourceInTagsAndSku_WithFeatureEnabled_OtherDtcPropertiesStillEnforced()
+        {
+            var services = new ServiceBuilder().WithFeatureOverrides(new(TestContext, RuntimeValuesInTagsAndSkuEnabled: true));
+            var result = CompilationHelper.Compile(services, @"
+resource testResource 'Microsoft.Storage/storageAccounts@2021-04-01' = {
+  name: this.exists() ? 'testStorage' : 'defaultStorage'
+  location: 'westus'
+  sku: {
+    name: this.existingResource().?sku.name ?? 'Standard_LRS'
+  }
+  kind: 'StorageV2'
+  tags: {
+    previousAccessTier: this.existingResource().?properties.accessTier ?? 'unknown'
+  }
+  properties: {
+    allowBlobPublicAccess: this.exists()
+  }
+}
+");
+
+            result.ExcludingLinterDiagnostics().Should().HaveDiagnostics(new[]
+            {
+                ("BCP120", DiagnosticLevel.Error, "This expression is being used in an assignment to the \"name\" property of the \"Microsoft.Storage/storageAccounts\" type, which requires a value that can be calculated at the start of the deployment."),
+            });
+        }
+
+        [TestMethod]
+        public void ThisNamespace_ExistingResourceInTagsAndSku_ForLoop_WithFeatureEnabled_ShouldSucceed()
+        {
+            var services = new ServiceBuilder().WithFeatureOverrides(new(TestContext, RuntimeValuesInTagsAndSkuEnabled: true));
+            var result = CompilationHelper.Compile(services, @"
+resource testResource 'Microsoft.Storage/storageAccounts@2021-04-01' = [for i in range(0, 3): {
+  name: 'testStorage-${i}'
+  location: 'westus'
+  sku: {
+    name: this.existingResource().?sku.name ?? 'Standard_LRS'
+  }
+  kind: 'StorageV2'
+  tags: {
+    previousAccessTier: this.existingResource().?properties.accessTier ?? 'unknown'
+  }
+  properties: {
+    allowBlobPublicAccess: this.exists()
+  }
+}]
+");
+
+            result.Should().NotHaveAnyDiagnostics();
+
+            using (new AssertionScope())
+            {
+                var template = result.Template;
+
+                template.Should().HaveValueAtPath("$.resources.testResource.tags.previousAccessTier", "[coalesce(tryGet(target('full'), 'properties', 'accessTier'), 'unknown')]");
+                template.Should().HaveValueAtPath("$.resources.testResource.sku.name", "[coalesce(tryGet(target('full'), 'sku', 'name'), 'Standard_LRS')]");
+                template.Should().HaveValueAtPath("$.resources.testResource.properties.allowBlobPublicAccess", "[not(empty(target('full')))]");
+            }
+        }
     }
 }

src/Bicep.Core/Configuration/ExperimentalFeaturesEnabled.cs

@@ -22,7 +22,8 @@ public record ExperimentalFeaturesEnabled(
     bool ResourceInfoCodegen,
     bool ModuleExtensionConfigs,
     bool UserDefinedConstraints,
-    bool DeployCommands)
+    bool DeployCommands,
+    bool RuntimeValuesInTagsAndSku)
 {
     public static ExperimentalFeaturesEnabled Bind(JsonElement element)
         => element.ToNonNullObject<ExperimentalFeaturesEnabled>();
@@ -42,5 +43,6 @@ public static ExperimentalFeaturesEnabled Bind(JsonElement element)
         ResourceInfoCodegen: false,
         ModuleExtensionConfigs: false,
         UserDefinedConstraints: false,
-        DeployCommands: false);
+        DeployCommands: false,
+        RuntimeValuesInTagsAndSku: false);
 }

src/Bicep.Core/Features/FeatureProvider.cs

@@ -54,6 +54,8 @@ public FeatureProvider(RootConfiguration configuration, IFileExplorer fileExplor
 
         public bool DeployCommandsEnabled => configuration.ExperimentalFeaturesEnabled.DeployCommands;
 
+        public bool RuntimeValuesInTagsAndSkuEnabled => configuration.ExperimentalFeaturesEnabled.RuntimeValuesInTagsAndSku;
+
         private static bool ReadBooleanEnvVar(string envVar, bool defaultValue)
             => bool.TryParse(Environment.GetEnvironmentVariable(envVar), out var value) ? value : defaultValue;
 

src/Bicep.Core/Features/IFeatureProvider.cs

@@ -37,6 +37,8 @@ public interface IFeatureProvider
 
     bool DeployCommandsEnabled { get; }
 
+    bool RuntimeValuesInTagsAndSkuEnabled { get; }
+
     IEnumerable<(string name, bool impactsCompilation, bool usesExperimentalArmEngineFeature)> EnabledFeatureMetadata
     {
         get
@@ -57,6 +59,7 @@ public interface IFeatureProvider
                 (ModuleExtensionConfigsEnabled, "Enable defining extension configs for modules", true, true),
                 (UserDefinedConstraintsEnabled, "Enable @validate() decorator", true, true),
                 (DeployCommandsEnabled, "Enable deploy commands", true, true),
+                (RuntimeValuesInTagsAndSkuEnabled, "Enable runtime values in tags and SKU", true, true),
             })
             {
                 if (enabled)

src/Bicep.Core/Features/RecordBasedFeatureProvider.cs

@@ -25,5 +25,6 @@ public class RecordBasedFeatureProvider(ExperimentalFeaturesEnabled features) :
         public bool ModuleExtensionConfigsEnabled => features.ModuleExtensionConfigs;
         public bool UserDefinedConstraintsEnabled => features.UserDefinedConstraints;
         public bool DeployCommandsEnabled => features.DeployCommands;
+        public bool RuntimeValuesInTagsAndSkuEnabled => features.RuntimeValuesInTagsAndSku;
     }
 }

src/Bicep.Core/TypeSystem/DeployTimeConstantContainerVisitor.cs

@@ -3,6 +3,7 @@
 
 using Bicep.Core.Semantics;
 using Bicep.Core.Syntax;
+using Bicep.Core.TypeSystem.Providers.Az;
 using Bicep.Core.TypeSystem.Types;
 
 namespace Bicep.Core.TypeSystem
@@ -64,6 +65,14 @@ public override void VisitObjectPropertySyntax(ObjectPropertySyntax syntax)
             if (syntax.TryGetTypeProperty(this.semanticModel) is { } typeProperty &&
                 typeProperty.Flags.HasFlag(TypePropertyFlags.DeployTimeConstant))
             {
+                // Skip DTC validation for tags and sku properties when the experimental feature is enabled.
+                if (this.semanticModel.Features.RuntimeValuesInTagsAndSkuEnabled &&
+                    syntax.TryGetKeyText() is AzResourceTypeProvider.ResourceTagsPropertyName or AzResourceTypeProvider.ResourceSkuPropertyName)
+                {
+                    base.VisitObjectPropertySyntax(syntax);
+                    return;
+                }
+
                 // The property type exists and and has the DTC flag.
                 this.deployTimeConstantContainers.Add(syntax);
             }

src/Bicep.Core/TypeSystem/Providers/Az/AzResourceTypeProvider.cs

@@ -23,6 +23,8 @@ public class AzResourceTypeProvider : ResourceTypeProviderBase, IResourceTypePro
         public const string ResourceNamePropertyName = "name";
         public const string ResourceTypePropertyName = "type";
         public const string ResourceApiVersionPropertyName = "apiVersion";
+        public const string ResourceTagsPropertyName = "tags";
+        public const string ResourceSkuPropertyName = "sku";
 
         public const string ResourceTypeDeployments = "Microsoft.Resources/deployments";
         public const string ResourceTypeResourceGroup = "Microsoft.Resources/resourceGroups";
@@ -58,10 +60,10 @@ public static readonly ImmutableSortedSet<string> ReadWriteDeployTimeConstantPro
             "extendedLocation",
             "zones",
             "plan",
-            "sku",
+            ResourceSkuPropertyName,
             "identity",
             "managedByExtended",
-            "tags",
+            ResourceTagsPropertyName,
             "asserts",
         ];
 

src/vscode-bicep/schemas/bicepconfig.schema.json

@@ -984,6 +984,10 @@
         "deployCommands": {
           "type": "boolean",
           "description": "Allows you to access the 'deploy', 'what-if' and 'teardown' commands. See https://aka.ms/bicep/experimental-features#deploycommands"
+        },
+        "runtimeValuesInTagsAndSku": {
+          "type": "boolean",
+          "description": "Allows the use of runtime values (such as references to resources or this.existingResource()) in tags and sku properties. See https://aka.ms/bicep/experimental-features#runtimevaluesintagsandsku"
         }
       },
       "additionalProperties": false