[CMake] how to deprecate a target?

[Bram de Greve]

That is unfortunate ... do you know any not-so-nice ways?

So, what would you recommend here?

I'm deprecating the old ways to use the Foo package (using Foo_LIBRARIES 
and Foo_INCLUDE_DIRS. You know, the cmake 2.x way of things). I can do 
that nicely with variable watches.

But what about the target names?  If I want to guarantee a seamless 
transition period, I should opt to keep using the "foo" target names.  
But then there's no way to "upgrade" to "Foo::foo" targets without 
breakage, since there's no deprecation strategy. And I can't use target 
aliases, since that is not allowed on imported targets.

To answer my own question, I think the best thing is to move to the 
"Foo::foo" targets right now.  There's at least one downstream package 
that will be hurt by this, but the damage is less than waiting for 
everyone to have moved to the "foo" target first.

Best,

Bram.


On 6/29/2018 20:22, Robert Maynard wrote:
> I am not aware of a nice way to setup CMake to error out if a user
> links to `foo` instead of `Foo::foo`.
> On Fri, Jun 29, 2018 at 2:05 AM Bram de Greve <bram at cocamware.com> wrote:
>> Hi all,
>>
>> Consider this situation.  I'm building a Foo packaged, to be used by a
>> Bar project.
>>
>> Foo used to export its target as simply foo.
>> Now it exports its target as Foo::foo.
>>
>> Bar contains this:
>> add_library(bar ...)
>> target_link_libraries(bar foo)
>>
>> This of course must now be:
>> add_library(bar ...)
>> target_link_libraries(bar Foo::foo)
>>
>> But if bar still links to the foo instead of Foo::foo, then CMake
>> doesn't really complain.  foo doesn't exist, but configures and
>> generates just fine.  Of course, you'll face strange build errors, from
>> which it isn't immediately apparent what's causing this ...
>>
>> How can I make sure CMake will complain loudly when bar still links to foo?
>>
>> Thanks,
>> Bram.
>>
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