[wix-devs] Pull Request #119

[Ron Martin]

Pull Request #119

The issue to which I refer as the CodeBase Issue, has to do with 
multiple places within the Wix 4 product that, for one reason or 
another, attempt to determine the file from which the currently 
executing code was loaded. One of the situations in which this might 
occur includes a vast number of system-level tests with names that begin 
with "CanBuild". This  can happens when the test needs to find 
wixnative.exe or WixToolset.Sdk.props.  Here, we are generally looking 
at a system that has built the Wix 4 product, but there might be 
scenarios in which these tests might be run during or after the 
installation of Wix 4 on a machine that is, for our purposes, only used 
to create installation packages and never used to build Wix 4, itself. 
Such tests might be run from the command line or from Visual Studio.

Beyond these tests, there might be other scenarios in which the Wix 4 
product wants to know from where it was loaded. There are a couple of 
problems with trying to determine how a particular piece of code got 
loaded into the current process. The current code relies on either on a 
.NET Framework 4.72 API or a .NET Core 3.1 API, neither of which is 
available in .NET Core 5.0 or later. In .NET Core 5.0 and later, you 
can't depend on much that is operating-system dependent.

We need a classification of all the scenarios in which this situation 
arises that recognizes the actual problem that is currently being solved 
(or perhaps just being attacked) by using knowledge of the image source. 
Then we need a way to provide the necessary knowledge where it is needed.

When tests are run from disposable file systems, the actual path to the 
loaded image is typically in the temp directory of the user account 
running the test. This is very different from a non-test situation.

I'm sure that I don't grasp all of the issues involved, but I have been 
looking at this issue (among others) for at least nine months. I think 
that it is time for some guidance from and decision making by those 
holding the keys to the realm.

Ron Martin
cpuwzd