When <AppId> is child of <Package>: System.ArgumentNullException during build

[dbengle]

Bugs

If this issue is a bug:

• Which version of WiX are you building with?
  WiX 4.0.2

• Which version of Visual Studio are you building with (if any)?
  Visual Studio 2022 17.7.4

• Which version of the WiX Toolset Visual Studio Extension are you building with (if any)?
  HeatWave for VS2022

• Which version of .NET are you building with?
  4.8

• If the problem occurs when installing your packages built with WiX, what is the version of Windows the package is running on?
  n/a

• Describe the problem and the steps to reproduce it.

Add an <AppId> element like this as a direct child of the <Package> element:

 <AppId Id="{1edc7500-0c88-11d3-afe6-0000836054d2}" />

When you try to build the package, it will fail with the following error:
wix.exe : error WIX0001: System.ArgumentNullException: Value cannot be null.

If you remove the <AppId> element, the problem goes away.
This worked in WiX 3.14.

• Describe the behavior you expected and how it differed from the actual behavior.

When you try to build the package, it will fail with the following error:

 wix.exe : error WIX0001: System.ArgumentNullException: Value cannot be null.

If you remove the <AppId> element, the problem goes away.

This worked in WiX 3.14.

[dbengle]

The call stack looks like this:

wix.exe : error WIX0001: System.ArgumentNullException: Value cannot be null. [C:\Projects\ZDD\SetupZDD\Package\Package.wixproj]
Parameter name: componentId (TaskId:53)
at WixToolset.Core.ExtensibilityServices.ParseHelper.CreateRegistrySymbol(IntermediateSection section, SourceLineNumber sourceLineNumbers, RegistryRootType root, String key, String name, String value, String componentId, RegistryValueType valueType, RegistryValueActionType valueAction) in D:\a\wix\wix\src\wix\WixToolset.Core\ExtensibilityServices\ParseHelper.cs:line 172 (TaskId:53)
at WixToolset.Core.CompilerCore.CreateRegistryStringSymbol(SourceLineNumber sourceLineNumbers, RegistryRootType root, String key, String name, String value, String componentId) in D:\a\wix\wix\src\wix\WixToolset.Core\CompilerCore.cs:line 306 (TaskId:53)
at WixToolset.Core.Compiler.ParseAppIdElement(XElement node, String componentId, YesNoType advertise, String fileServer, String typeLibId, String typeLibVersion) in D:\a\wix\wix\src\wix\WixToolset.Core\Compiler.cs:line 571 (TaskId:53)
at WixToolset.Core.Compiler.ParsePackageElement(XElement node) in D:\a\wix\wix\src\wix\WixToolset.Core\Compiler_Package.cs:line 239 (TaskId:53)
at WixToolset.Core.Compiler.ParseWixElement(XElement node) in D:\a\wix\wix\src\wix\WixToolset.Core\Compiler.cs:line 221 (TaskId:53)
at WixToolset.Core.Compiler.Compile(ICompileContext context) in D:\a\wix\wix\src\wix\WixToolset.Core\Compiler.cs:line 129 (TaskId:53)
at WixToolset.Core.CommandLine.BuildCommand.CompilePhase(IDictionary2 preprocessorVariables, IEnumerable1 sourceFiles, IReadOnlyCollection`1 includeSearchPaths, CancellationToken cancellationToken) in D:\a\wix\wix\src\wix\WixToolset.Core\CommandLine\BuildCommand.cs:line 188 (TaskId:53)
at WixToolset.Core.CommandLine.BuildCommand.ExecuteAsync(CancellationToken cancellationToken) in D:\a\wix\wix\src\wix\WixToolset.Core\CommandLine\BuildCommand.cs:line 159 (TaskId:53)
at WixToolset.Tools.Program.Run(IServiceProvider serviceProvider, IMessageListener listener, String[] args, CancellationToken cancellationToken) in D:\a\wix\wix\src\wix\wix\Program.cs:line 103 (TaskId:53)
at WixToolset.Tools.Program.

d__0.MoveNext() (TaskId:53)
The command exited with code -2147467261. (TaskId:53)
Output Property: _WixBuildExitCode=-2147467261 (TaskId:53)
Done executing task "WixBuild" -- FAILED. (TaskId:53)

[dbengle]

The System.ArgumentNullException is because the parent component ID is null. Since the parent is a package, there is no parent component. However, this did work in v3.14, and the schema documentation states that the parent of can be a .