[cmake-developers] file(DOWNLOAD) + EXPECTED_HASH security issue

[David Cole]

> Once a command reports an error CMake will not generate the project
> so it is not worth allowing the configuration to do much after that.
> Failure of file(DOWNLOAD) should either be a cmake::FATAL_ERROR or
> just a STATUS setting with no CMake Error.  The signature needs a
> way for CMake to know which one to do.
>
> I'm fine with changing the current non-fatal error to a fatal error
> in the next release.

Would this be:
(1) an unconditional, always-in-effect change?
(2) a policy with a NEW behavior?
(3) a change activated only by use of a new keyword argument to 
file(DOWNLOAD ?

File download errors are quite common for many different reasons.... 
I'm not sure I like the idea of triggering a CMake fatal error for a 
corrupt download.


File download should mostly be a build-time step in my opinion. 
Configure should be as fast as possible, meaning: only do the minimum 
try_compiles necessary, and defer until build time things that take a 
long time, like download over a network.


?
D