Revert "Add automatic remote build detection for Python apps in func pack command (#4530)"

This reverts commit b791c6e.

Author: aishwaryabh

release_notes.md

@@ -10,5 +10,4 @@
 - Fix dotnet templates installation (#4538)
 - Disable diagnostic events in local development by replacing the `IDiagnosticEventRepository` with a `DiagnosticEventNullRepository` (#4542)
 - Add `func pack` support for in-proc functions (#4529)
-- Default to remote build for `func pack` for python apps (#4530)
 - Update `func init` to default to the .NET 8 template for in-proc apps (#4557)

src/Cli/func/Actions/AzureActions/PublishFunctionAppAction.cs

@@ -214,7 +214,7 @@ public override async Task RunAsync()
             var additionalAppSettings = await ValidateFunctionAppPublish(functionApp, workerRuntime, functionAppRoot);
 
             // Update build option
-            PublishBuildOption = ResolveBuildOptionHelper.ResolveBuildOption(PublishBuildOption, workerRuntime, functionApp, BuildNativeDeps, NoBuild);
+            PublishBuildOption = PublishHelper.ResolveBuildOption(PublishBuildOption, workerRuntime, functionApp, BuildNativeDeps, NoBuild);
 
             bool isNonCsxDotnetRuntime = WorkerRuntimeLanguageHelper.IsDotnet(workerRuntime) && !Csx;
 

src/Cli/func/Actions/LocalActions/PackAction.cs

@@ -1,4 +1,4 @@
-// Copyright (c) .NET Foundation. All rights reserved.
+// Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the MIT License. See LICENSE in the project root for license information.
 
 using Azure.Functions.Cli.Common;
@@ -88,10 +88,6 @@ public override async Task RunAsync()
             }
 
             var workerRuntime = WorkerRuntimeLanguageHelper.GetCurrentWorkerRuntimeLanguage(_secretsManager);
-
-            // Resolve build option to detect if remote build is needed (e.g., Python app on Windows)
-            var buildOption = ResolveBuildOptionHelper.ResolveBuildOption(BuildOption.Default, workerRuntime, site: null, BuildNativeDeps, noBuild: false);
-
             outputPath += Squashfs ? ".squashfs" : ".zip";
             if (FileSystemHelpers.FileExists(outputPath))
             {
@@ -113,7 +109,7 @@ public override async Task RunAsync()
             bool useGoZip = EnvironmentHelper.GetEnvironmentVariableAsBool(Constants.UseGoZip);
             TelemetryHelpers.AddCommandEventToDictionary(TelemetryCommandEvents, "UseGoZip", useGoZip.ToString());
 
-            var stream = await ZipHelper.GetAppZipFile(functionAppRoot, BuildNativeDeps, noBuild: false, buildOption: buildOption, additionalPackages: AdditionalPackages);
+            var stream = await ZipHelper.GetAppZipFile(functionAppRoot, BuildNativeDeps, BuildOption.Default, noBuild: false, additionalPackages: AdditionalPackages);
 
             if (Squashfs)
             {

src/Cli/func/Helpers/PublishHelper.cs

@@ -1,7 +1,8 @@
-// Copyright (c) .NET Foundation. All rights reserved.
+// Copyright (c) .NET Foundation. All rights reserved.
 // Licensed under the MIT License. See LICENSE in the project root for license information.
 
 using System.Net.Http.Handlers;
+using Azure.Functions.Cli.Arm.Models;
 using Azure.Functions.Cli.Common;
 
 namespace Azure.Functions.Cli.Helpers
@@ -25,6 +26,33 @@ public static GitIgnoreParser GetIgnoreParser(string workingDir)
             return null;
         }
 
+        public static BuildOption ResolveBuildOption(BuildOption currentBuildOption, WorkerRuntime runtime, Site site, bool buildNativeDeps, bool noBuild)
+        {
+            // --no-build and --build-native-deps will take precedence over --build local and --build remote
+            if (noBuild)
+            {
+                return BuildOption.None;
+            }
+
+            if (buildNativeDeps)
+            {
+                return BuildOption.Container;
+            }
+
+            if (currentBuildOption == BuildOption.Default)
+            {
+                // Change to remote build if, python app, has requirements.txt, requirements.txt has content
+                if (runtime == WorkerRuntime.Python &&
+                    FileSystemHelpers.FileExists(Constants.RequirementsTxt) &&
+                    new FileInfo(Path.Combine(Environment.CurrentDirectory, Constants.RequirementsTxt)).Length > 0)
+                {
+                    return BuildOption.Remote;
+                }
+            }
+
+            return currentBuildOption;
+        }
+
         public static async Task<HttpResponseMessage> InvokeLongRunningRequest(HttpClient client, ProgressMessageHandler handler, HttpRequestMessage request, long requestSize = 0, string prompt = null)
         {
             if (prompt == null)

src/Cli/func/Helpers/ResolveBuildOptionHelper.cs

@@ -34,7 +34,8 @@ public void Pack_Python_WorksAsExpected()
                 {
                     "host.json",
                     "requirements.txt",
-                    "function_app.py"
+                    "function_app.py",
+                    Path.Combine(".python_packages", "requirements.txt.md5")
                 });
         }
 
@@ -82,14 +83,22 @@ public void Pack_PythonFromCache_WorksAsExpected()
             firstPackResult.Should().HaveStdOutContaining("Creating a new package");
             firstPackResult.Should().NotHaveStdOutContaining(syncDirMessage);
 
+            // Verify .python_packages/requirements.txt.md5 file exists
+            var pythonPackagesMd5Path = Path.Combine(workingDir, ".python_packages", "requirements.txt.md5");
+            var packFilesToValidate = new List<(string FilePath, string[] ExpectedContent)>
+            {
+                (pythonPackagesMd5Path, new[] { string.Empty }) // Just check file exists, content can be empty
+            };
+            firstPackResult.Should().FilesExistsWithExpectContent(packFilesToValidate);
+
             // Step 3: Run pack again without changing requirements.txt (should use cache)
             var secondPackResult = funcPackCommand
                 .WithWorkingDirectory(workingDir)
                 .Execute([]);
 
             secondPackResult.Should().ExitWith(0);
             secondPackResult.Should().HaveStdOutContaining("Creating a new package");
-            secondPackResult.Should().NotHaveStdOutContaining(syncDirMessage);
+            secondPackResult.Should().HaveStdOutContaining(syncDirMessage);
 
             // Step 4: Update requirements.txt and pack again (should restore dependencies)
             var requirementsPath = Path.Combine(workingDir, "requirements.txt");
@@ -103,6 +112,9 @@ public void Pack_PythonFromCache_WorksAsExpected()
             thirdPackResult.Should().ExitWith(0);
             thirdPackResult.Should().HaveStdOutContaining("Creating a new package");
             thirdPackResult.Should().NotHaveStdOutContaining(syncDirMessage);
+
+            // Verify .python_packages/requirements.txt.md5 file still exists
+            thirdPackResult.Should().FilesExistsWithExpectContent(packFilesToValidate);
         }
     }
 }