(WiX) Install the same file in multiple locations

Question

For several files in my product, I need them to be copied to two different places during installation. For instance:

C:\Program Files (x86)\My Company\My App\foo\xyzzy.txt C:\Program Files (x86)\My Company\My App\bar\xyzzy.txt 

These two copies of xyzzy.txt are identical.

I would rather not take a dimensional blow with identical copies of the file in the closet. When playing with makecab, it seems that duplicate copies of files in the cab effectively double the size of the cab. For comparison, 7zip allows you to include a second copy at no cost.

Is it possible to have one copy of each file in the (built-in) package and install it in two different destinations? If so, how would you indicate this in WiX 3.5?

I assume that having two File elements with the same Id would be against XML rules and / or WiX component rules. On the other hand, if I have unique File elements, will the light just put two copies of the same file in the cabinet?

Answer 1

Yes, WiX 3 does this automatically. Just use the same Source attribute in different File elements. And, yes, you must provide the File elements with different identifier attributes.