Avoid creating installer node with duplicate NestedInstallerFile

src/WingetCreateCore/Common/PackageParser.cs

@@ -501,6 +501,14 @@ private static bool ParsePackageAndGenerateInstallerNodes(InstallerMetadata inst
 
                 foreach (NestedInstallerFile nestedInstallerFile in installerMetadata.NestedInstallerFiles)
                 {
+                    // Skip adding duplicate NestedInstallerFile object.
+                    if (baseInstaller.NestedInstallerFiles.Any(i =>
+                        i.RelativeFilePath == nestedInstallerFile.RelativeFilePath &&
+                        i.PortableCommandAlias == nestedInstallerFile.PortableCommandAlias))
+                    {
+                        continue;
+                    }
+
                     baseInstaller.NestedInstallerFiles.Add(new NestedInstallerFile
                     {
                         RelativeFilePath = nestedInstallerFile.RelativeFilePath,

src/WingetCreateTests/WingetCreateTests/Resources/TestPublisher.ZipMultipleInstallers.yaml

@@ -12,13 +12,23 @@ Installers:
   NestedInstallerType: exe
   NestedInstallerFiles:
   - RelativeFilePath: WingetCreateTestExeInstaller.exe
+    PortableCommandAlias: TestPortableCommandAlias
 - Architecture: x86
   InstallerType: zip
   InstallerUrl: https://fakedomain.com/WingetCreateTestZipInstaller.zip
   InstallerSha256: 8A052767127A6E2058BAAE03B551A807777BB1B726650E2C7E92C3E92C8DF80D
   NestedInstallerType: exe
   NestedInstallerFiles:
   - RelativeFilePath: WingetCreateTestExeInstaller.exe
+    PortableCommandAlias: TestPortableCommandAlias
+- Architecture: arm64
+  InstallerType: zip
+  InstallerUrl: https://fakedomain.com/WingetCreateTestZipInstaller.zip
+  InstallerSha256: 8A052767127A6E2058BAAE03B551A807777BB1B726650E2C7E92C3E92C8DF80D
+  NestedInstallerType: exe
+  NestedInstallerFiles:
+  - RelativeFilePath: WingetCreateTestExeInstaller.exe
+    PortableCommandAlias: TestPortableCommandAlias
 PackageLocale: en-US
 ManifestType: singleton
 ManifestVersion: 1.4.0

src/WingetCreateTests/WingetCreateTests/UnitTests/UpdateCommandTests.cs

@@ -823,6 +823,44 @@ public async Task UpdateZipWithMsix()
             Assert.IsTrue(initialSecondInstaller.InstallerSha256 != updatedSecondInstaller.InstallerSha256, "InstallerSha256 should be updated");
         }
 
+        /// <summary>
+        /// Verifies that updating a zip package with multiple zip installers works as expected.
+        /// </summary>
+        /// <returns>A <see cref="Task"/> representing the asynchronous unit test.</returns>
+        [Test]
+        public async Task UpdateMultipleZipInstallers()
+        {
+            TestUtils.InitializeMockDownloads(TestConstants.TestZipInstaller);
+
+            string installerUrl = $"https://fakedomain.com/{TestConstants.TestZipInstaller}";
+            (UpdateCommand command, var initialManifestContent) = GetUpdateCommandAndManifestData("TestPublisher.ZipMultipleInstallers", null, this.tempPath, new[] { $"{installerUrl}|x64", $"{installerUrl}|x86", $"{installerUrl}|arm64" });
+
+            var updatedManifests = await RunUpdateCommand(command, initialManifestContent);
+            Assert.IsNotNull(updatedManifests, "Command should have succeeded");
+
+            var initialManifests = Serialization.DeserializeManifestContents(initialManifestContent);
+            var initialInstallers = initialManifests.SingletonManifest.Installers;
+            var initialFirstInstaller = initialInstallers[0];
+            var initialSecondInstaller = initialInstallers[1];
+            var initialThirdInstaller = initialInstallers[2];
+
+            var updatedInstallerManifest = updatedManifests.InstallerManifest;
+            var updatedFirstInstaller = updatedInstallerManifest.Installers[0];
+            var updatedSecondInstaller = updatedInstallerManifest.Installers[1];
+            var updatedThirdInstaller = updatedInstallerManifest.Installers[2];
+
+            Assert.IsTrue(updatedInstallerManifest.InstallerType == InstallerType.Zip, "InstallerType should be ZIP");
+            Assert.IsTrue(updatedInstallerManifest.NestedInstallerType == NestedInstallerType.Exe, "NestedInstallerType should be EXE");
+            Assert.IsTrue(updatedInstallerManifest.NestedInstallerFiles.Count == 1, "NestedInstallerFiles list should contain only one member");
+
+            Assert.IsTrue(initialFirstInstaller.NestedInstallerFiles[0].RelativeFilePath == updatedInstallerManifest.NestedInstallerFiles[0].RelativeFilePath, "RelativeFilePath should be preserved.");
+            Assert.IsTrue(initialFirstInstaller.NestedInstallerFiles[0].PortableCommandAlias == updatedInstallerManifest.NestedInstallerFiles[0].PortableCommandAlias, "PortableCommandAlias should be preserved.");
+
+            Assert.IsTrue(initialFirstInstaller.InstallerSha256 != updatedFirstInstaller.InstallerSha256, "InstallerSha256 should be updated");
+            Assert.IsTrue(initialSecondInstaller.InstallerSha256 != updatedSecondInstaller.InstallerSha256, "InstallerSha256 should be updated");
+            Assert.IsTrue(initialThirdInstaller.InstallerSha256 != updatedThirdInstaller.InstallerSha256, "InstallerSha256 should be updated");
+        }
+
         /// <summary>
         /// Verifies that moving common installer fields to the root of the manifest works as expected.
         /// </summary>