[cmake-developers] How to handle package Config.cmake files with dependencies ?

[David Cole]

On Mar 7, 2012, at 5:39 PM, Alexander Neundorf <neundorf at kde.org> wrote:

> On Wednesday 07 March 2012, Brad King wrote:
>> On 3/7/2012 9:49 AM, Michael Hertling wrote:
>>> been found, but in module mode, AFAIK, it's set to Foo_DIR-NOTFOUND
>>> even if a find module has succeeded
>> 
>> The Foo_DIR variable is not set or added to the cache at all if
>> a FindFoo module is loaded regardless of whether it succeeds.
>> It is only if no FindFoo module is found that Foo_DIR appears.
>> 
>>> my question is still: How can I figure out in a reliable manner
>>> that FIND_PACKAGE(Foo ...) has found neither FindFoo.cmake nor
>>> FooConfig.cmake?
>> 
>> The call site should *know* whether it is intending to use a
>> Find module or look for a package config file based on whether
>> the the author adds a Find module to CMAKE_MODULE_PATH.
> 
> Yes.
> 
>> If using a Find module then use its documentation to check the
>> result.  FPHSA sets FOO_FOUND.  Otherwise if using Config mode
>> then check Foo_FOUND.
>> 
>> Actually, the documentation of find_package says:
>> 
>>  <package>_FOUND will be set to indicate whether the package was found.
>> 
>> Config mode *always* sets that.  If it isn't set correctly
>> by a Find module that is a bug in the Find module IMO.
> 
> Yes.
> 
>> FPHSA should be fixed to set both Foo_FOUND and FOO_FOUND.
>> I know Alex always says that we should use UPPERCASE_VARS
>> instead of ExactCase_VARS but the *ONLY* reason ever given
>> is because "most" modules have done that historically.
> 
> Yes.
> Beside that I don't have any preferences whether it should be ExactCase or 
> UPPER_CASE, I think both naming conventions are ok.
> 
>> That argument just extends the problem into the future as
>> more and more new modules use the confusing convention.
> 
> If we all agree consciously that going with ExactCase is ok although the 
> majority of existing Find-modules uses UPPER_CASE then I won't object.
> 
> Alex
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I prefer exact case, too. We should adopt the convention of using exact case moving forward, and add exact case equivalents to the existing upper case ones.


David