On Sat, 16 Apr 2011 17:57:23 +0200, Francis Moreau said:

> The user modify a file, then instead of calling 'make' (because he
> forgets) run the script that send the kernel image through the net on
> a test machine. Since the user had already compiled the kernel before,
>  the kernel image exists but is outdated.

As I said, this is an example of a broken development environment, or
possibly a broken developer. :)

> How can a script detect this case if it doesn't call 'make' in its turn ?

Why do you care about detecting it without calling make?  Just go ahead and
*do* it, if the kernel is up to date it won't take long.  With a completely
cold cache, it takes about 90 seconds on my laptop.  Cache-hot is closer to 45
seconds. If that's too long, buy the developer a real machine or a compile
farm.  If that's a problem, you'll need to put the developer inside a script
that enforces "you *vill* do dis, then you *vill* do dat" fascism so the
programmer never gets a chance to do something you didn't expect.