[KPhotoAlbum] Marble versioning

[Johannes Zarl-Zierl]

Hi,

Am Montag, 26. Juli 2021, 22:26:51 CEST schrieb Tobias Leupold:
> You're right -- but if we do a version check like this, we can as well
> simply check for no version at all, as we do now ;-)

To be honest, it probably doesn't make a difference if we check for a minimum 
version of 0.28 at all - you would need an ancient version of marble for that 
dependency to be not fulfilled.

> Unless Marble changes it's versioning scheme, I think this will be the only
> reasonable option ...

It just did:
https://invent.kde.org/education/marble/-/merge_requests/45

Good thing that you brought up the topic - I kind of forgot about the whole 
MR. With this change, cmake version compatibility for marble was switched from 
SameMajorVersion to AnyNewerVersion, which resolves this issue.

In the meantime, Haralds approach is basically the same one that I would take:

find_package(Marble)
if((${Marble_VERSION} VERSION_LESS 0.28)
    # instead of bailing out with a message use a find_package call so that 
messages are the same as normally, and so that feature_summary works 
correctly:
    find_package(Marble 0.28 REQUIRED)
endif()

Cheers,
  Johannes