ign -> gz FindXXX migration : gz-cmake

[methylDragon]

See: gazebo-tooling/release-tools#698

NOTE: THIS MUST BE REBASE MERGED!! Files were moved!

Description

All FindXXX.cmake files have been hard migrated to Gz.

Some downstream packages still use them via the gz_find_package() call, so an intercepting redirection of any Ign prefixed find calls to Gz has been implemented (with warning.)

Hard-tocks

• <Package_name>_FIND_VERSION_MINOR CMake variables are being used (but populated automatically from the find_package() call, which might be the Gz or Ign version
• Hard-tocked these since the file names changed (and the only way they'll be found is if the redirected find_package() call uses the Gz prefixed package name, which will set the Gz prefixed _FIND_VERSION_MINOR var)
• Likewise with XXX_FIND_COMPONENTS
  • These are internal to the best of my knowledge, so the user shouldn't be using them

Tick-tocks

• Downstream libs are using XXX_FOUND variables, I will ticktock those
• Explicitly being set() with an Ign prefix, just in case they'll be used downstream

Notes

• gz_import_target is being called to generate targets.

The call itself is made of several components:

  gz_import_target(IgnOGRE2
    TARGET_NAME IgnOGRE2::IgnOGRE2
    LIB_VAR OGRE2_LIBRARIES
    INCLUDE_VAR OGRE2_INCLUDE_DIRS)

That is,

  gz_import_target(<package_name>
    TARGET_NAME <TARGET>::<TARGET>
    LIB_VAR OGRE2_LIBRARIES
    INCLUDE_VAR OGRE2_INCLUDE_DIRS)

• The package name is hard-tocked, and library aliases are installed for the imported target name.
• In order to add alias targets, however, I needed to set the imported add_library() call to GLOBAL visibility.
  • c409c94#diff-42bab6079b4ba6149374a4f37a702aabec4cd82b534287747b8014a4a1a39eb8R110
  • I don't know what implications this will have on performance, but it works. To be safe we should remove the GLOBAL keyword once we don't need the tick-tock.

[scpeters]

testing sdformat against this branch in macOS and windows CI using the ci_matching_branch/ trick in gazebosim/sdformat#1072

[scpeters]

this change in PACKAGE_NAME means there is no longer a matching ${PACKAGE_NAME}_pretty variable, since that is set just before this code block. This could be fixed by moving that code block to after this if logic

[methylDragon]

Ah, nice catch! It seems despite my best efforts I got bamboozled by macro substitution 😓

Fixed: 98aadc5

Upon approval, I'll squash all the non file-migration commits into one so when we rebase merge we'll just have two commits!

[methylDragon]

Gonna squash all the non moving commits 👀

For posterity: