[cmake-developers] Setting target properties before the target is defined ?

[Alexander Neundorf]

On Sunday 17 February 2013, Brad King wrote:
> On 2/15/2013 5:54 PM, Alexander Neundorf wrote:
> > The thing is, if I generate an error at configure time if at the end of a
> > directory a target has been used but has not been defined, i.e. a target
> > Foo has been imported which links against a missing imported target, it
> > would still be possible that the project can build successfully if this
> > bad imported target Foo is simply not used, e.g. because Foo_FOUND is
> > set to FALSE.
> 
> Just to make sure I understand correctly, you're bringing up a use case
> where an imported target's dependencies are not satisfied but it does
> not matter when the imported target is not used by the project?

Yes.
But I wouldn't call it use case, but a case which accidentially works right 
now, and which a new cmake release should not break.

> > How about that: when in the exported and then imported Target.cmake a
> > used target is not yet defined, this target name is added to a cmake
> > variable. When then cmake calculates the linking, and it can't find a
> > target, it checks whether the name is contained in this cmake variable.
> > If so, it errors out instead of assuming it is the name of a library.
> 
> Yes, the variable would simply be collecting names that, in the scope
> of its directory, are expected to be target names.  It may be better
> to use a directory property and then have the generate-time check
> look in the current directory and up.  That will avoid problems with
> scoping of the variable if the project loads the file from inside
> a function scope.

Oh, right, from inside a function scope...

Alex