RE: auto-dep cannot possibly work?

[Mark Galeck (CW)]

Paul wrote:
>Yes, it's true that IF someone adds a new header file that has the same
name as an existing header file, and IF that new header file appears in
a directory that is before the existing header directory on the -I list
for the compiler, and IF the addition of that header file does not
require the source file or any other header file that the source file
includes to be modified (and hence rebuilt), THEN make will not
recompile (...)

To go from an extra manual step in this extremely unusual situation to
"cannot possibly work" seems to me to be a reach.

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Paul, I thought some more here and looked at our code, and in fact, I beg your 
pardon, this is not "extremely unusual" but quite common in fact!  There are 
lots of header files with the same name, like "config.h", or "includes.h" 
(which just lists other include files).  Developers are apt to add more.  If 
they do, the first IF is satisfied, and if you think about it for a moment, you 
will realize that is very very hard to check the second IF, because there could 
be things like 
#include "../../config.h"

Essentially, every time somebody adds another header file (which happens all 
the time),  I have to tell them:  

"if you add a header file, check if there is already another one with the same 
name elsewhere in the system, and if so, the dependencies will not work and you 
have to rebuild the whole thing"

I am pretty sure they will laugh at me.  Or maybe I am just pessimistic :)