WIX automation and patch behavior once registeration of DLL is changed

Question

I have basic issue that i don't understand, we use HEAT to consume directory of artifacts that part of them are COM DLL. As part of the crated WXS file i see that there are elements for registry like:

<Component Id="cmpAE50B39B8817E1840F09193686006FFA" Guid="*">
  <File Id="fil7BDB953AB6AAEC9E98E28F49D87BABA3" KeyPath="yes" Source="SourceDir\ucfDistribution.dll">
    <TypeLib Id="{88B7EEC8-DF2B-11D4-A508-005004ED3088}" Description="ucfDistribution" HelpDirectory="dir83BF4093F80DD11BB416BF39954702C2" Language="0" MajorVersion="14" MinorVersion="13">
      <Class Id="{3AA1580F-1DA2-44A5-B581-98D861C2A0CD}" Context="InprocServer32" Description="ucfDistribution.ucfCMAXMLClass" ThreadingModel="apartment" Version="14.13" Programmable="yes">
        <ProgId Id="ucfDistribution.ucfCMAXMLClass" Description="ucfDistribution.ucfCMAXMLClass" />
      </Class>
      <Interface Id="{A98DFC45-F161-442D-9A10-3CB3103B524F}" Name="ucfCMAXMLClass" ProxyStubClassId="{00020424-0000-0000-C000-000000000046}" ProxyStubClassId32="{00020424-0000-0000-C000-000000000046}" />
    </TypeLib>
  </File>
  <RegistryValue Root="HKCR" Key="Interface\{D41A9260-ED8A-44BC-8700-08D3ADB20CFE}\Forward" Value="{A98DFC45-F161-442D-9A10-3CB3103B524F}" Type="string" Action="write" />
</Component>

Lets say that during patch the file is changed & registration is change in such way that the KEY of the registry changed (was originally Interface\{D41A9260-ED8A-44BC-8700-08D3ADB20CFE}\Forward)

What will happen during patch will the previous registry be removed or will it stay orphaned.

I suspect that since the component key (file) is updated this means that the component will install and will leave the previous key (registry) * i didn't test this yet

Answer 1

Correct. A patch is really just a transform applied to the MSI then the result is repaired. Since the transform will change the MSI, it won't know about the old registry keys and leave them untouched.

Your patch is breaking the Component Rules: http://robmensching.com/blog/posts/2003/10/18/Component-Rules-101 and that is not supported by the Windows Installer.