ABI break between clang 17 & 18 causing linkage errors with abseil

[h-vetinari]

The change from clang 17 to clang 18 seems to have cause an ABI break w.r.t. symbol mangling, causing failures of the following kind when different builds are mixed

yld[23066]: Symbol not found: __ZN4absl12lts_2024072212log_internal10LogMessagelsIiLi0EEERS2_RKT_
  Referenced from: <7DD6F527-7A4A-3649-87B6-D68B25F8B594> /Users/runner/miniconda3/envs/test/lib/libprotobuf.28.2.0.dylib
  Expected in:     <D623F952-8116-35EC-859D-F7F8D5DD7699> /Users/runner/miniconda3/envs/test/lib/libabsl_log_internal_message.2407.0.0.dylib
Subprocess aborted

To fix this, I had added #86, but this has just moved the problem further down the stack. We've rebuilt

• MNT: rerender re2-feedstock#87
• MNT: rerender libprotobuf-feedstock#244
• MNT: rerender grpc-cpp-feedstock#387

so far, but it appears from post-merge comments in #86 that also other places like arrow are affected.

[h-vetinari]

Ah well... conda-forge/libprotobuf-feedstock#244 was applied to 5.28.3, but our pinning is on 5.28.2 😑

However, at least that means we can just migrate for 5.28.3 to ensure stuff gets built consistently

[traversaro]

After #86 I think I am starting observing in downstream CI the opposite problem in downstream builds of jax.

E   ImportError: dlopen(/Users/runner/micromamba/envs/adamdev/lib/python3.13/site-packages/jaxlib/xla_extension.so, 0x0002): Symbol not found: __ZN4absl12lts_2024072212log_internal10LogMessagelsIPKvLi0EEERS2_RKT_
E     Referenced from: <05E679BA-8DDA-37BF-BA62-E2CC01CA7001> /Users/runner/micromamba/envs/adamdev/lib/python3.13/site-packages/jaxlib/xla_extension.so
E     Expected in:     <D623F952-8116-35EC-859D-F7F8D5DD7699> /Users/runner/micromamba/envs/adamdev/lib/libabsl_log_internal_message.2407.0.0.dylib

see ami-iit/adam#115 for more details.

Just a bit of recap, from what I understand the situation is the following:

clang version	symbol present	demangled symbol present	libabseil version
17	__ZN4absl12lts_2024072212log_internal10LogMessagelsIPKvLi0EEERS2_RKT_	_absl::lts_20240722::log_internal::LogMessage& absl::lts_20240722::log_internal::LogMessage::operator<< <void const*, 0>(void const* const&)	cxx17_hf9b8971_1
18	__ZN4absl12lts_2024072212log_internal10LogMessagelsIiLi0EEERS2_RKT_	_absl::lts_20240722::log_internal::LogMessage& absl::lts_20240722::log_internal::LogMessage::operator<< <int, 0>(int const&)	cxx17_h07bc746_2

The problem is that the latest build of jaxlib was built with clang 17, so it is not compatible with libabseil compiled with clang 18.

[sanurielf]

I found a similar issue but with libgpr:

ImportError: dlopen(.pixi/envs/dev/lib/python3.12/site-packages/grpc/_cython/cygrpc.cpython-312-darwin.so, 0x0002): Symbol not found: __ZN4absl12lts_2024072212log_internal10LogMessagelsIiLi0EEERS2_RKT_
  Referenced from: <4DB83F7F-C593-3BDC-AEB2-798416EDF135> .pixi/envs/dev/lib/libgpr.44.0.0.dylib
  Expected in:     <D623F952-8116-35EC-859D-F7F8D5DD7699> .pixi/envs/dev/lib/libabsl_log_internal_message.2407.0.0.dylib

[traversaro]

The problem is that the latest build of jaxlib was built with clang 17, so it is not compatible with libabseil compiled with clang 18.

I opened conda-forge/jaxlib-feedstock#296 for visibility.

[h-vetinari]

It would be nice if we could patch abseil to contain both symbols.