[libcxx] Unmatched _LIBCPP_POP_MACROS with LIBCXX_ENABLE_LOCALIZATION=OFF

[s-barannikov]

With LIBCXX_ENABLE_LOCALIZATION=OFF a bunch of tests fail to compile with an error:

libcxx/test-suite-install/include/c++/v1/istream:1385:1: error: pragma pop_macro could not pop 'min', no matching push_macro [-Werror,-Wignored-pragmas]
# |  1385 | _LIBCPP_POP_MACROS
# |       | ^

The corresponding _LIBCPP_PUSH_MACROS is guarded by #if _LIBCPP_HAS_LOCALIZATION, while _LIBCPP_POP_MACROS isn't.

[ldionne]

This is strange, that didn't come up in our tests. Can you describe exactly what you're running?

[s-barannikov]

I'm running libc++ test suite. The tests that unexpectedly fail are:

std/containers/container.adaptors/flat.map/flat.map.iterators/reverse_iterator.pass.cpp
std/containers/container.adaptors/flat.multimap/flat.multimap.iterators/reverse_iterator.pass.cpp
std/containers/container.adaptors/flat.multiset/flat.multiset.iterators/reverse_iterator.pass.cpp
std/containers/container.adaptors/flat.set/flat.set.iterators/reverse_iterator.pass.cpp

Used CMake options

      -DLIBUNWIND_ENABLE_ASSERTIONS=OFF
      -DLIBUNWIND_ENABLE_SHARED=OFF
      -DLIBUNWIND_ENABLE_STATIC=ON
      -DLIBUNWIND_ENABLE_THREADS=OFF
      -DLIBUNWIND_IS_BAREMETAL=ON
      -DLIBUNWIND_SHARED_OUTPUT_NAME="unwind-shared"
      -DLIBUNWIND_USE_COMPILER_RT=ON

      -DLIBCXXABI_BAREMETAL=ON
      -DLIBCXXABI_ENABLE_ASSERTIONS=OFF
      -DLIBCXXABI_ENABLE_EXCEPTIONS=OFF
      -DLIBCXXABI_ENABLE_SHARED=OFF
      -DLIBCXXABI_ENABLE_STATIC_UNWINDER=OFF
      -DLIBCXXABI_ENABLE_THREADS=OFF
      -DLIBCXXABI_NON_DEMANGLING_TERMINATE=OFF
      -DLIBCXXABI_SHARED_OUTPUT_NAME="c++abi-shared"
      -DLIBCXXABI_USE_COMPILER_RT=ON

      -DLIBCXX_ABI_UNSTABLE=ON
      -DLIBCXX_ENABLE_EXCEPTIONS=OFF
      -DLIBCXX_ENABLE_FILESYSTEM=OFF
      -DLIBCXX_ENABLE_MONOTONIC_CLOCK=OFF
      -DLIBCXX_ENABLE_RANDOM_DEVICE=OFF
      -DLIBCXX_ENABLE_RTTI=OFF
      -DLIBCXX_ENABLE_SHARED=OFF
      -DLIBCXX_ENABLE_THREADS=OFF
      -DLIBCXX_ENABLE_LOCALIZATION=OFF
      -DLIBCXX_ENABLE_WIDE_CHARACTERS=OFF
      -DLIBCXX_SHARED_OUTPUT_NAME="c++-shared"
      -DLIBCXX_STATICALLY_LINK_ABI_IN_STATIC_LIBRARY=ON
      -DLIBCXX_USE_COMPILER_RT=ON

There is nothing special in a custom lit config / arguments.
The compiler is (almost) ToT clang.

[frederick-vs-ja]

This mismatch seems to be real and is probably introduced by #108637.

It seems that we almost never test including <istream> with localization disabled. I wonder whether we should test this.

std/containers/container.adaptors/flat.map/flat.map.iterators/reverse_iterator.pass.cpp
std/containers/container.adaptors/flat.multimap/flat.multimap.iterators/reverse_iterator.pass.cpp
std/containers/container.adaptors/flat.multiset/flat.multiset.iterators/reverse_iterator.pass.cpp
std/containers/container.adaptors/flat.set/flat.set.iterators/reverse_iterator.pass.cpp

At least these test files shouldn't include <iostream>, I believe.

[ldionne]

Both @mordante and I are unable to reproduce this issue locally. That's weird.

But by looking at the code I can tell the POP_MACROS is in the wrong place. These tests also clearly shouldn't include <iostream>.

Finally, I do think we should be testing the inclusion of those headers since they're supposed to be no-ops now. I'll make a patch.

[s-barannikov]

Both @mordante and I are unable to reproduce this issue locally. That's weird.

Just in case, here are the used features:

All available features: 32-bit-pointer, buildhost=linux, c++26, c++experimental,
can-create-symlinks, clang, clang-21, clang-21.0, clang-21.0.0,
diagnose-if-support, enable-benchmarks=no, executor-has-no-bash,
gcc-style-warnings, has-fblocks, has-fconstexpr-steps, host-has-gdb-with-python,
libcpp-abi-no-compressed-pair-padding, libcpp-abi-version=2,
libcpp-hardening-mode=none, libcpp-has-abi-fix-unordered-container-size-type,
libcpp-has-no-availability-markup, libcpp-has-no-unicode, no-exceptions,
no-filesystem, no-localization, no-monotonic-clock, no-random-device, no-rtti,
no-threads, no-tzdb, no-wide-characters, objective-c++, optimization=speed,
std-at-least-c++03, std-at-least-c++11, std-at-least-c++14, std-at-least-c++17,
std-at-least-c++20, std-at-least-c++23, std-at-least-c++26, stdlib=libc++,
stdlib=llvm-libc++, target=xx-unknown-none, thread-safety, verify-support

Not sure if it makes a difference, but C++ modules are disabled.

[ldionne]

I did #134874 to solve the immediate problem but I am also working on a patch to enable the testing of headers guarded with NO_LOCALIZATION in the CI, since they don't produce a hard error anymore.