CCache with Visual Studio Generator causing files to be compiled always

Hello All,

I picked up compiler caching subject again for C++ on windows using Visual Studio Generator. I was reading ProfessionalCMake_18th_Edition.pdf and this book has complete section compiler cache wehere in compile caching using ccache is being exained greatly. I must say its great book. Thanks @craig.scott for the book.

I followed book and it seems caching is working (not 100% but greatly) but one thing I noticed, even though I have compiled my library and without any change in source file, if I compile same library again it compiles the all sources of that library. This is very unusual. I tried to figure out what is happening but could not understand the same.

So every time I build it always builds all source file which seems not right behaviour.

I am attaching the sample reproducible project . Would appreciate help on any direction here.
WorkspaceCCache.zip (6.3 KB)