Fix: patch bundled Boost hash.hpp for C++17 std::unary_function removal#2750
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In C++17, std::unary_function was removed. The bundled Boost headers in tecio (boost/container_hash/hash.hpp) use std::unary_function in hash_base under a guard (_HAS_AUTO_PTR_ETC) that only activates on MSVC. On MacOS clang and Linux GCC with C++17, the guard never triggers, causing a compilation error. Fix: replaced std::unary_function inheritance in the #else branch with explicit typedef declarations, identical to what the #if branch already does correctly. Fixes su2code#2583
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Thanks for the review @joshkellyjakcom I believe this is ready — the fix is minimal, targeted, and consistent with how the #if branch already handles this. But I want to make sure I'm not missing anything before this gets merged. Let me know if there's anything else needed to get this across the line? I want to make sure this meets the project's standards. |
pcarruscag
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I'm afraid I can't accept an opaque change to a binary file from a first-time contributor.
If there is no other way to apply the patch, I'll wait for Josh to look at the changes thoroughly.
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Root Cause
boost/container_hash/hash.hpphas a guard#if defined(_HAS_AUTO_PTR_ETC)which is MSVC-only. On MacOS/clang and GCC with C++17, this guard never
activates, so
hash_baseinherits fromstd::unary_functionwhich wasremoved in C++17, causing a build failure.
Fix
Patched the
#elsebranch ofhash_baseinexternals/tecio/boost.tar.gzto use explicit
typedefdeclarations instead ofstd::unary_functioninheritance. This matches what the
#ifbranch already does correctly forMSVC. No behaviour change.
Verification
Zero occurrences of
unary_functionremain inboost/container_hash/hash.hppafter repacking.Files Changed
externals/tecio/boost.tar.gz— one struct patched inboost/container_hash/hash.hppPR Checklist
[ * ] I am submitting my contribution to the develop branch.
[ * ] My contribution generates no new compiler warnings (try with --warnlevel=3 when using meson).
[ * ] My contribution is commented and consistent with SU2 style (https://su2code.github.io/docs_v7/Style-Guide/).
[ ] I used the pre-commit hook to prevent dirty commits and used pre-commit run --all to format old commits.
[ ] I have added a test case that demonstrates my contribution, if necessary.
[ ] I have updated appropriate documentation (Tutorials, Docs Page, config_template.cpp), if necessary.
Fixes #2583