Add analyzers and code fixes for Dapr workflows

Introduce `WorkflowRegistrationAnalyzer` and `WorkflowActivityAnalyzer` to validate workflow and activity registrations in the DI container. Implement corresponding code fix providers to suggest automatic fixes. Add tests to ensure functionality and robustness of the Dapr workflow framework.

Signed-off-by: Nils Gruson <[email protected]>

src/Dapr.Workflow.Analyzers/AnalyzerReleases.Shipped.md

@@ -4,4 +4,5 @@
 
 Rule ID | Category | Severity | Notes
 --------|----------|----------|--------------------
-DAPR1001| Usage    | Warning    | The class '{0}' is not registered
+DAPR1001| Usage    | Warning    | The workflow class '{0}' is not registered
+DAPR1002| Usage    | Warning    | The workflow activity class '{0}' is not registered

src/Dapr.Workflow.Analyzers/WorkflowActivityRegistrationCodeFixProvider.cs

@@ -0,0 +1,124 @@
+using System.Collections.Immutable;
+using System.Composition;
+using Microsoft.CodeAnalysis;
+using Microsoft.CodeAnalysis.CodeActions;
+using Microsoft.CodeAnalysis.CodeFixes;
+using Microsoft.CodeAnalysis.CSharp;
+using Microsoft.CodeAnalysis.CSharp.Syntax;
+using Microsoft.CodeAnalysis.Formatting;
+
+namespace Dapr.Workflow.Analyzers;
+
+/// <summary>
+/// Provides code fixes for DAPR1002 diagnostic.
+/// </summary>
+[ExportCodeFixProvider(LanguageNames.CSharp, Name = nameof(WorkflowActivityRegistrationCodeFixProvider))]
+[Shared]
+public class WorkflowActivityRegistrationCodeFixProvider : CodeFixProvider
+{
+    /// <summary>
+    /// Gets the diagnostic IDs that this provider can fix.
+    /// </summary>
+    public override ImmutableArray<string> FixableDiagnosticIds => ImmutableArray.Create("DAPR1002");
+
+    /// <summary>
+    /// Registers the code fix for the diagnostic.
+    /// </summary>
+    public override Task RegisterCodeFixesAsync(CodeFixContext context)
+    {
+        var title = "Register workflow activity";
+        context.RegisterCodeFix(
+            CodeAction.Create(
+                title,
+                createChangedDocument: c => RegisterWorkflowActivityAsync(context.Document, context.Diagnostics.First(), c),
+                equivalenceKey: title),
+            context.Diagnostics);
+        return Task.CompletedTask;
+    }
+
+    private async Task<Document> RegisterWorkflowActivityAsync(Document document, Diagnostic diagnostic, CancellationToken cancellationToken)
+    {
+        var root = await document.GetSyntaxRootAsync(cancellationToken).ConfigureAwait(false);
+        var diagnosticSpan = diagnostic.Location.SourceSpan;
+
+        var oldInvocation = root?.FindToken(diagnosticSpan.Start).Parent?.AncestorsAndSelf().OfType<InvocationExpressionSyntax>().First();
+
+        if (oldInvocation is null)
+            return document;
+
+        if (root == null || oldInvocation == null)
+            return document;
+
+        // Extract the workflow activity type name
+        var workflowActivityType = oldInvocation.ArgumentList.Arguments.FirstOrDefault()?.Expression.ToString();
+
+        if (string.IsNullOrEmpty(workflowActivityType))
+            return document;
+
+        // Get the compilation
+        var compilation = await document.Project.GetCompilationAsync(cancellationToken).ConfigureAwait(false);
+
+        if (compilation == null)
+            return document;
+
+        InvocationExpressionSyntax? addDaprWorkflowInvocation = null;
+        SyntaxNode? targetRoot = null;
+        Document? targetDocument = null;
+
+        // Iterate through all syntax trees in the compilation
+        foreach (var syntaxTree in compilation.SyntaxTrees)
+        {
+            var syntaxRoot = await syntaxTree.GetRootAsync(cancellationToken).ConfigureAwait(false);
+
+            addDaprWorkflowInvocation = syntaxRoot.DescendantNodes()
+                .OfType<InvocationExpressionSyntax>()
+                .FirstOrDefault(invocation => invocation.Expression is MemberAccessExpressionSyntax memberAccess &&
+                                              memberAccess.Name.Identifier.Text == "AddDaprWorkflow");
+
+            if (addDaprWorkflowInvocation != null)
+            {
+                targetRoot = syntaxRoot;
+                targetDocument = document.Project.GetDocument(syntaxTree);
+                break;
+            }
+        }
+
+        if (addDaprWorkflowInvocation == null || targetRoot == null || targetDocument == null)
+            return document;
+
+        // Find the options lambda block
+        var optionsLambda = addDaprWorkflowInvocation.ArgumentList.Arguments
+            .Select(arg => arg.Expression)
+            .OfType<SimpleLambdaExpressionSyntax>()
+            .FirstOrDefault();
+
+        // Extract the parameter name from the lambda expression
+        var parameterName = optionsLambda.Parameter.Identifier.Text;
+
+        // Create the new workflow registration statement
+        var registerWorkflowStatement = SyntaxFactory.ParseStatement($"{parameterName}.RegisterActivity<{workflowActivityType}>();");
+
+        if (optionsLambda == null || optionsLambda.Body is not BlockSyntax optionsBlock)
+            return document;
+
+        // Add the new registration statement to the options block
+        var newOptionsBlock = optionsBlock.AddStatements(registerWorkflowStatement);
+
+        // Replace the old options block with the new one
+        var newRoot = targetRoot.ReplaceNode(optionsBlock, newOptionsBlock);
+
+        // Format the new root.
+        newRoot = Formatter.Format(newRoot, document.Project.Solution.Workspace);
+
+        return targetDocument.WithSyntaxRoot(newRoot);
+    }
+
+    /// <summary>
+    /// Gets the FixAllProvider for this code fix provider.
+    /// </summary>
+    /// <returns>The FixAllProvider instance.</returns>
+    public override FixAllProvider? GetFixAllProvider()
+    {
+        return WellKnownFixAllProviders.BatchFixer;
+    }
+}