Add Regenerate feature to Update workflow using shared helper

tools/azsdk-cli/Azure.Sdk.Tools.Cli.Tests/Tools/TypeSpec/TspClientUpdateToolTests.cs

@@ -3,8 +3,7 @@
 using Azure.Sdk.Tools.Cli.Tools;
 using Microsoft.Extensions.Logging.Abstractions;
 using Azure.Sdk.Tools.Cli.Helpers;
-using System;
-using System.IO;
+using Azure.Sdk.Tools.Cli.Models.Responses;
 
 namespace Azure.Sdk.Tools.Cli.Tests.Tools.CustomizedCodeUpdateTool;
 
@@ -63,9 +62,10 @@ public async Task Auto_NoChanges_TerminatesAtValidation()
     {
         var svc = new MockNoChangeLanguageService();
         var resolver = new SingleResolver(svc);
-        var tool = new TspClientUpdateTool(new NullLogger<TspClientUpdateTool>(), new NullOutputService(), resolver);
+        var tsp = new MockTspHelper();
+        var tool = new TspClientUpdateTool(new NullLogger<TspClientUpdateTool>(), new NullOutputService(), resolver, tsp);
         var pkg = CreateTempPackageDir();
-        var run = await tool.UpdateAsync("placeholder.tsp", packagePath: pkg, ct: CancellationToken.None);
+        var run = await tool.UpdateAsync("0123456789abcdef0123456789abcdef01234567", packagePath: pkg, ct: CancellationToken.None);
         Assert.That(run.Session, Is.Not.Null, "Session should be created");
         Assert.That(run.Session!.LastStage, Is.EqualTo(UpdateStage.Validated), "No changes now proceed through validation");
     // Slim model: no stored API change count; reaching Validated implies no changes or all handled.
@@ -76,21 +76,23 @@ public async Task Auto_WithChanges_Validated()
     {
         var svc = new MockChangeLanguageService();
         var resolver = new SingleResolver(svc);
-        var tool = new TspClientUpdateTool(new NullLogger<TspClientUpdateTool>(), new NullOutputService(), resolver);
+        var tsp = new MockTspHelper();
+        var tool = new TspClientUpdateTool(new NullLogger<TspClientUpdateTool>(), new NullOutputService(), resolver, tsp);
         var pkg = CreateTempPackageDir();
-        var first = await tool.UpdateAsync("placeholder-change.tsp", packagePath: pkg, ct: CancellationToken.None);
+        var first = await tool.UpdateAsync("89abcdef0123456789abcdef0123456789abcdef", packagePath: pkg, ct: CancellationToken.None);
         Assert.That(first.Session, Is.Not.Null);
         Assert.That(first.Session.LastStage, Is.EqualTo(UpdateStage.Validated), "Single-pass should reach validated");
     }
 
     [Test]
     public async Task Validation_Failure_Then_AutoFixes_Applied()
     {
-        var tool = new TspClientUpdateTool(new NullLogger<TspClientUpdateTool>(), new NullOutputService(), new SingleResolver(new MockNoChangeLanguageService()));
+        var tsp = new MockTspHelper();
+        var tool = new TspClientUpdateTool(new NullLogger<TspClientUpdateTool>(), new NullOutputService(), new SingleResolver(new MockNoChangeLanguageService()), tsp);
         int calls = 0; var svc = new TestLanguageServiceFailThenFix(() => calls++);
-        tool = new TspClientUpdateTool(new NullLogger<TspClientUpdateTool>(), new NullOutputService(), new SingleResolver(svc));
+        tool = new TspClientUpdateTool(new NullLogger<TspClientUpdateTool>(), new NullOutputService(), new SingleResolver(svc), tsp);
         var pkg = CreateTempPackageDir();
-        var resp = await tool.UpdateAsync("spec.tsp", packagePath: pkg, ct: CancellationToken.None);
+        var resp = await tool.UpdateAsync("fedcba9876543210fedcba9876543210fedcba98", packagePath: pkg, ct: CancellationToken.None);
         Assert.That(resp.Session, Is.Not.Null);
         Assert.That(resp.Session!.LastStage, Is.EqualTo(UpdateStage.Validated));
         Assert.That(resp.Session.RequiresManualIntervention, Is.False);
@@ -129,3 +131,11 @@ private class SingleResolver : IClientUpdateLanguageServiceResolver
         public Task<IClientUpdateLanguageService?> ResolveAsync(string? packagePath, CancellationToken ct = default) => Task.FromResult<IClientUpdateLanguageService?>(_svc);
     }
 }
+
+internal class MockTspHelper : ITspClientHelper
+{
+    public Task<TspToolResponse> ConvertSwaggerAsync(string swaggerReadmePath, string outputDirectory, bool isArm, bool fullyCompatible, bool isCli, CancellationToken ct)
+        => Task.FromResult(new TspToolResponse { IsSuccessful = true, TypeSpecProjectPath = outputDirectory });
+    public Task<TspToolResponse> UpdateGenerationAsync(string tspLocationPath, string outputDirectory, bool isCli, CancellationToken ct)
+        => Task.FromResult(new TspToolResponse { IsSuccessful = true, TypeSpecProjectPath = outputDirectory });
+}

tools/azsdk-cli/Azure.Sdk.Tools.Cli/Helpers/ITspClientHelper.cs

@@ -5,14 +5,22 @@
 namespace Azure.Sdk.Tools.Cli.Helpers;
 
 /// <summary>
-/// Abstraction for running common tsp-client commands (convert, update, diff, map, etc.).
+/// Abstraction for running common tsp-client commands (convert, update, generate, init).
 /// This centralizes npx invocation logic so multiple tools (Generate, Build, Update workflows)
-/// can share a single implementation without instantiating each other.
+/// can share a single implementation without duplicating code.
 /// </summary>
 public interface ITspClientHelper
 {
     /// <summary>
     /// Runs `tsp-client convert --swagger-readme <readme> --output-dir <out>` with optional flags.
     /// </summary>
     Task<TspToolResponse> ConvertSwaggerAsync(string swaggerReadmePath, string outputDirectory, bool isArm, bool fullyCompatible, bool isCli, CancellationToken ct);
+
+    /// <summary>
+    /// Runs `tsp-client update` to regenerate a TypeSpec client into the specified output directory.
+    /// </summary>
+    /// <param name="tspLocationPath">Path to the tsp-location.yaml file.</param>
+    /// <param name="outputDirectory">Directory to place regenerated output (created if missing, must be empty or created new).</param>
+    /// <param name="isCli">True when invoked from CLI flow (suppresses duplicate streamed output in error text).</param>
+    Task<TspToolResponse> UpdateGenerationAsync(string tspLocationPath, string outputDirectory, bool isCli, CancellationToken ct);
 }

tools/azsdk-cli/Azure.Sdk.Tools.Cli/Helpers/TspClientHelper.cs

@@ -54,4 +54,37 @@ public async Task<TspToolResponse> ConvertSwaggerAsync(string swaggerReadmePath,
             TypeSpecProjectPath = outputDirectory
         };
     }
+
+    public async Task<TspToolResponse> UpdateGenerationAsync(string tspLocationPath, string outputDirectory, bool isCli, CancellationToken ct)
+    {
+        logger.LogInformation("tsp-client update (tsp-location): {loc} -> {out}", tspLocationPath, outputDirectory);
+        if (!File.Exists(tspLocationPath))
+        {
+            return new TspToolResponse { ResponseError = $"tsp-location.yaml not found at path: {tspLocationPath}" };
+        }
+        var workingDir = Path.GetDirectoryName(Path.GetFullPath(tspLocationPath))!;
+        var npxOptions = new NpxOptions(
+            "@azure-tools/typespec-client-generator-cli",
+            ["tsp-client", "update"],
+            logOutputStream: true,
+            workingDirectory: workingDir
+        );
+
+        var result = await npxHelper.Run(npxOptions, ct);
+        if (result.ExitCode != 0)
+        {
+            return new TspToolResponse
+            {
+                ResponseError = isCli
+                    ? "Failed to regenerate TypeSpec client, see details in the above logs."
+                    : "Failed to regenerate TypeSpec client, see generator output below" + Environment.NewLine + result.Output
+            };
+        }
+
+        return new TspToolResponse
+        {
+            IsSuccessful = true,
+            TypeSpecProjectPath = outputDirectory
+        };
+    }
 }

tools/azsdk-cli/Azure.Sdk.Tools.Cli/Models/Responses/TspClientUpdateResponse.cs

@@ -70,7 +70,12 @@ public enum UpdateStage
     /// <summary>
     /// Post-apply validation (build / tests / lint) executed and results captured.
     /// </summary>
-    Validated
+    Validated,
+
+    /// <summary>
+    /// Update failed due to an unknown error.
+    /// </summary>
+    Failed
 }
 
 public class ClientUpdateSessionState

tools/azsdk-cli/Azure.Sdk.Tools.Cli/Tools/TypeSpec/TspClientUpdateTool.cs

@@ -18,22 +18,24 @@ public class TspClientUpdateTool : MCPTool
     private readonly ILogger<TspClientUpdateTool> logger;
     private readonly IOutputHelper output;
     private readonly IClientUpdateLanguageServiceResolver languageServiceResolver;
-    private readonly Argument<string> specPathArg = new(name: "spec-path", description: "Path to the .tsp specification file") { Arity = ArgumentArity.ExactlyOne };
+    private readonly ITspClientHelper tspClientHelper;
+    private readonly Argument<string> updateCommitSha = new(name: "update-commit-sha", description: "SHA of the commit to apply update changes for") { Arity = ArgumentArity.ExactlyOne };
     private readonly Option<string?> newGenOpt = new(["--new-gen"], () => "./tmpgen", "Directory for regenerated TypeSpec output (optional)");
 
-    public TspClientUpdateTool(ILogger<TspClientUpdateTool> logger, IOutputHelper output, IClientUpdateLanguageServiceResolver languageServiceResolver)
+    public TspClientUpdateTool(ILogger<TspClientUpdateTool> logger, IOutputHelper output, IClientUpdateLanguageServiceResolver languageServiceResolver, ITspClientHelper tspClientHelper)
     {
         this.logger = logger;
         this.output = output;
         this.languageServiceResolver = languageServiceResolver;
+        this.tspClientHelper = tspClientHelper;
         CommandHierarchy = [ SharedCommandGroups.TypeSpec ];
     }
 
     public override Command GetCommand()
     {
         var cmd = new Command("customized-update",
             description: "Update customized TypeSpec-generated client code. Runs the full pipeline by default: regenerate -> diff -> map -> propose -> apply");
-        cmd.AddArgument(specPathArg);
+        cmd.AddArgument(updateCommitSha);
         cmd.AddOption(SharedOptions.PackagePath);
         cmd.AddOption(newGenOpt);
         cmd.SetHandler(async ctx => await HandleUpdate(ctx, ctx.GetCancellationToken()));
@@ -43,43 +45,31 @@ public override Command GetCommand()
     public override Task HandleCommand(InvocationContext ctx, CancellationToken ct) => Task.CompletedTask;
 
     [McpServerTool(Name = "azsdk_tsp_update"), Description("Update customized TypeSpec-generated client code")]
-    public async Task<TspClientUpdateResponse> UpdateAsync(string specPath, string packagePath, CancellationToken ct = default)
+    public Task<TspClientUpdateResponse> UpdateAsync(string commitSha, string packagePath, CancellationToken ct = default)
+        => RunUpdateAsync(commitSha, packagePath, newGenPath: null, ct);
+
+    private async Task<TspClientUpdateResponse> RunUpdateAsync(string commitSha, string packagePath, string? newGenPath, CancellationToken ct)
     {
         try
         {
-            logger.LogInformation($"Starting client update for package at: {packagePath}");
+            logger.LogInformation("Starting client update for package at: {packagePath} (regenDir: {regenDir})", packagePath, newGenPath);
             if (!Directory.Exists(packagePath))
             {
                 SetFailure(1);
-                return new TspClientUpdateResponse
-                {
-                    ErrorCode = "1",
-                    ResponseError = $"Package path does not exist: {packagePath}",
-                    Message = ""
-                };
+                return new TspClientUpdateResponse { ErrorCode = "1", ResponseError = $"Package path does not exist: {packagePath}" };
             }
-            if (string.IsNullOrWhiteSpace(specPath))
+            if (string.IsNullOrWhiteSpace(commitSha))
             {
                 SetFailure(1);
-                return new TspClientUpdateResponse
-                {
-                    ErrorCode = "1",
-                    ResponseError = $"Spec path is required.",
-                    Message = ""
-                };
+                return new TspClientUpdateResponse { ErrorCode = "1", ResponseError = "Commit SHA is required." };
             }
             var resolved = await languageServiceResolver.ResolveAsync(packagePath, ct);
             if (resolved == null)
             {
                 SetFailure(1);
-                return new TspClientUpdateResponse
-                {
-                    ErrorCode = "NoLanguageService",
-                    ResponseError = "Could not resolve a client update language service.",
-                    Message = ""
-                };
+                return new TspClientUpdateResponse { ErrorCode = "NoLanguageService", ResponseError = "Could not resolve a client update language service." };
             }
-            return await UpdateCoreAsync(specPath, packagePath, resolved, ct);
+            return await UpdateCoreAsync(commitSha, packagePath, resolved, ct, newGenPath);
         }
         catch (Exception ex)
         {
@@ -88,12 +78,42 @@ public async Task<TspClientUpdateResponse> UpdateAsync(string specPath, string p
         }
     }
 
-    private async Task<TspClientUpdateResponse> UpdateCoreAsync(string specPath, string packagePath, IClientUpdateLanguageService languageService, CancellationToken ct)
+    private async Task<TspClientUpdateResponse> UpdateCoreAsync(string commitSha, string packagePath, IClientUpdateLanguageService languageService, CancellationToken ct, string? newGenPath)
     {
-        var session = new ClientUpdateSessionState { SpecPath = specPath };
+        var session = new ClientUpdateSessionState { SpecPath = commitSha };
+
+        // Determine output directory for new generation: use provided newGenPath (CLI option) or fallback.
+        var regenDir = ResolveRegenDirectory(packagePath, newGenPath);
+        if (!Directory.Exists(regenDir))
+        {
+            Directory.CreateDirectory(regenDir);
+        }
+        session.NewGeneratedPath = regenDir;
+
+        // Locate the existing tsp-location.yaml file within the provided packagePath and overwrite the commit: value with the new sha
+        var tspLocationPath = Path.Combine(packagePath, "tsp-location.yaml");
+        if (File.Exists(tspLocationPath))
+        {
+            var tspLocationContent = await File.ReadAllTextAsync(tspLocationPath, ct);
+            tspLocationContent = tspLocationContent.Replace("commit: ", $"commit: {commitSha}");
+            await File.WriteAllTextAsync(tspLocationPath, tspLocationContent, ct);
+        }
 
-        // Regenerate (placeholder)
+        // Invoke tsp-client update
+        var regenResult = await tspClientHelper.UpdateGenerationAsync(tspLocationPath, regenDir, isCli: false, ct);
+        if (!regenResult.IsSuccessful)
+        {
+            SetFailure(1);
+            session.LastStage = UpdateStage.Failed;
+            return new TspClientUpdateResponse
+            {
+                Session = session,
+                ErrorCode = "RegenerateFailed",
+                ResponseError = regenResult.ResponseError
+            };
+        }
         session.LastStage = UpdateStage.Regenerated;
+        // Now after regeneration, we have old generated at packagePath, new generation at regenDir to perform a diff
 
         var apiChanges = await languageService.DiffAsync(packagePath, session.NewGeneratedPath);
         session.LastStage = UpdateStage.Diffed;
@@ -154,12 +174,13 @@ private static async Task<TspClientUpdateResponse> ValidateWithAutoFixAsync(Clie
 
     private async Task HandleUpdate(InvocationContext ctx, CancellationToken ct)
     {
-        var spec = ctx.ParseResult.GetValueForArgument(specPathArg);
+    var spec = ctx.ParseResult.GetValueForArgument(updateCommitSha);
         var packagePath = ctx.ParseResult.GetValueForOption(SharedOptions.PackagePath);
+        var newGenPath = ctx.ParseResult.GetValueForOption(newGenOpt);
         try
         {
-            logger.LogInformation($"Starting client update for package at: {packagePath}");
-            var resp = await UpdateAsync(spec, packagePath, ct);
+            logger.LogInformation("Starting client update (CLI) for package at: {packagePath} with new-gen: {newGenPath}", packagePath, newGenPath);
+            var resp = await RunUpdateAsync(spec, packagePath, newGenPath, ct);
             output.Output(resp);
         }
         catch (Exception ex)
@@ -168,4 +189,18 @@ private async Task HandleUpdate(InvocationContext ctx, CancellationToken ct)
             output.OutputError(new TspClientUpdateResponse { ResponseError = ex.Message, ErrorCode = "ClientUpdateFailed" });
         }
     }
+
+    private static string ResolveRegenDirectory(string packagePath, string? newGenPath)
+    {
+        if (string.IsNullOrWhiteSpace(newGenPath))
+        {
+            return Path.Combine(packagePath, "_generated-new");
+        }
+        // If user supplied a relative path, place it under the package path for isolation.
+        if (!Path.IsPathRooted(newGenPath))
+        {
+            return Path.GetFullPath(Path.Combine(packagePath, newGenPath));
+        }
+        return Path.GetFullPath(newGenPath);
+    }
 }