unfortunately, we're currently stuck supporting gcc 11 which doesn't have atomic shared ptr yet:

include/c++/11/atomic:211:7: error: static_assert failed due to requirement '__is_trivially_copyable(std::shared_ptr<const OSDMap>)' "std::atomic requires a trivially copyable type"
      static_assert(__is_trivially_copyable(_Tp),
      ^             ~~~~~~~~~~~~~~~~~~~~~~~~~~~~

this came up recently in #60225, where we needed ifdefs for gcc version

Ah, shucks! That complicates this. We /could/ work around it with what amount to a wrapper for atomic_store() that does a capability check (#if __cpp_lib_atomic_shared_ptr), but unless we're doing it project wide (and that seems like somewhat pointless effort as the "right" solution is to move to atomic<shared_ptr<>>) I feel like it adds quite a bit of complexity to an already trickier-than-it-looks[1] bit of code. Perhaps it's best to let this one be for now.

1. Noticing that OSDMap.h (1838) has its /own/ Seastar ifdef of OSDMapRef for the global namespace, which is different than the PastIntervals::OSDMapRef appearing in osd_types.h, and looking at the way the tests use it, it becomes curious that the overload interval_rep::check_new_interval() appears to only be there FOR wrangling the atomic types... to pass the values into a function that doesn't do atomic checks. I get a bit unclear on what was actually intended .

Closing this for now-- it will make more sense to address once we can drop support for GCC11.

See-also: https://lists.ceph.io/hyperkitty/list/[email protected]/thread/LNMXUFBMFXHIXX334DYOMW5K4PYN4YIM/