Update cmake minimum version to 3.24

[hnakamur]

• LINK_GROUP RESCAN is used in src/iocore/net/CMakeLists.txt. It was added in CMake version 3.24.
• CMAKE_COMPILE_WARNING_AS_ERROR is used in CMakePresets.json. It was added in CMake version 3.24.

CMake 3.22.1 on Ubuntu 22.04 causes the following link error for src/iocore/net/test_net.

FAILED: src/iocore/net/test_net                                                                                                                                                                                     : && /usr/bin/c++ -pthread -g -Wl,--allow-multiple-definition src/iocore/net/CMakeFiles/test_net.dir/libinknet_stub.cc.o src/iocore/net/CMakeFiles/test_net.dir/NetVCTest.cc.o src/iocore/net/CMakeFiles/test_net.dir/unit_tests/test_ProxyProtocol.cc.o src/iocore/net/CMakeFiles/test_net.dir/unit_tests/test_SSLSNIConfig.cc.o src/iocore/net/CMakeFiles/test_net.dir/unit_tests/test_YamlSNIConfig.cc.o src/iocore/net/CMakeFiles/test_net.dir/unit_tests/unit_test_main.cc.o -o src/iocore/net/test_net  -Wl,-rpath,/root/trafficserver/build-default/lib/swoc:/root/trafficserver/build-default/lib/yamlcpp  -ldl  src/tscore/libtscore.a  src/proxy/libproxy.a  src/iocore/net/libinknet.a  src/iocore/eventsystem/libinkevent.a  src/iocore/cache/libinkcache.a  src/mgmt/rpc/librpcpublichandlers.a  src/api/libtsapibackend.a  src/shared/liboverridable_txn_vars.a  src/proxy/http/libhttp.a  src/iocore/hostdb/libinkhostdb.a  src/proxy/http2/libhttp2.a  src/proxy/http/remap/libhttp_remap.a  src/proxy/logging/liblogging.a  src/iocore/dns/libinkdns.a  src/proxy/libproxy.a  src/iocore/net/libinknet.a  src/iocore/cache/libinkcache.a  src/mgmt/rpc/librpcpublichandlers.a  src/api/libtsapibackend.a  src/shared/liboverridable_txn_vars.a  src/proxy/http/libhttp.a  src/iocore/hostdb/libinkhostdb.a  src/proxy/http2/libhttp2.a  src/proxy/http/remap/libhttp_remap.a  src/proxy/logging/liblogging.a  src/iocore/dns/libinkdns.a  src/mgmt/rpc/libjsonrpc_protocol.a  /usr/lib/x86_64-linux-gnu/libssl.so  src/iocore/aio/libaio.a  lib/fastlz/libfastlz.a  /usr/lib/x86_64-linux-gnu/libz.so  /usr/lib/x86_64-linux-gnu/liblzma.so  src/iocore/utils/libinkutils.a  src/proxy/hdrs/libhdrs.a  src/iocore/eventsystem/libinkevent.a  src/records/librecords.a  src/tscore/libtscore.a  /usr/lib/x86_64-linux-gnu/libcrypto.so  /usr/lib/x86_64-linux-gnu/libpcre.so  /usr/lib/x86_64-linux-gnu/libresolv.so  /usr/lib/x86_64-linux-gnu/libcap.so  /usr/lib/x86_64-linux-gnu/libhwloc.so  src/tsutil/libtsutil.a  lib/swoc/libswoc-1.5.12.so  lib/yamlcpp/libyaml-cppd.so.0.8.0  -ldl  /usr/lib/x86_64-linux-gnu/libpcre2-8.so && :                                             /usr/bin/ld: src/proxy/http/remap/libhttp_remap.a(RemapConfig.cc.o): warning: relocation against `_ZN7IpAllow14accept_check_pE' in read-only section `.text._ZN7IpAllow17enableAcceptCheckEb[_ZN7IpAllow17enableAcceptCheckEb]'                                                                                                                                                                                                         /usr/bin/ld: src/proxy/http/remap/libhttp_remap.a(AclFiltering.cc.o): in function `src_ip_category_info_t::ask_ip_allow_about_category(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, swoc::_1_5_13::IPAddr const&) const':                                                                                                                                                                    /root/trafficserver/src/proxy/http/remap/AclFiltering.cc:36: undefined reference to `IpAllow::ip_category_contains_addr(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, swoc::_1_5_13::IPAddr const&)'
/usr/bin/ld: src/proxy/http/remap/libhttp_remap.a(RemapConfig.cc.o): in function `remap_load_plugin(char const* const*, int, url_mapping*, char*, int, int, int*, UrlRewrite*)':
/root/trafficserver/src/proxy/http/remap/RemapConfig.cc:949: undefined reference to `isPluginDynamicReloadEnabled()'
/usr/bin/ld: src/proxy/http/remap/libhttp_remap.a(RemapConfig.cc.o): in function `IpAllow::enableAcceptCheck(bool)':
/root/trafficserver/include/proxy/IPAllow.h:398: undefined reference to `IpAllow::accept_check_p'
/usr/bin/ld: /root/trafficserver/include/proxy/IPAllow.h:399: undefined reference to `IpAllow::accept_check_p'
/usr/bin/ld: warning: creating DT_TEXTREL in a PIE
collect2: error: ld returned 1 exit status

CMake 3.22.1 on Ubuntu 22.04 causes the following warning when running cmake --preset default:

CMake Warning:
  Manually-specified variables were not used by the project:

    CMAKE_COMPILE_WARNING_AS_ERROR

CMake 3.24 does not cause the above problems.

[maskit]

We might want to stick with 3.20. ATS 10 meeting note says 3.20 is the minimum version required. The note doesn't mention where the requirement came from, but I don't think 3.20 is a random version.

@moonchen It seems like the link issue remains on some platforms.

[moonchen]

I would like to upgrade to 3.24 if possible. The circular dependency issues with GNU ld are difficult to work around without link groups. It looks like we've been using CMAKE_COMPILE_WARNING_AS_ERROR in presets for the past two years.

[maskit]

I suppose CMAKE_COMPILE_WARNING_AS_ERROR is ok because it just doesn't do the job on an old cmake. Although we see the warning, it does not block building ATS. But LINK_GROUP does.

I personally don't mind upgrading to 3.24, but I think it should be proposed on the dev list.

[hnakamur]

If we stick with CMake 3.20, we can use a workaround which uses -Wl,--start-group and -Wl,--end-group manually (hnakamur@83784aa).

target_link_libraries(
  test_net
  PRIVATE catch2::catch2
          ts::tscore
          -Wl,--start-group
          ${LINK_GROUP_LIBS}
          -Wl,--end-group
          ts::tsutil
          ts::inkevent
          libswoc::libswoc
)

If we upgrade CMake to 3.24, we might want add an instruction to install CMake >=3.24 from https://github.com/Kitware/CMake/releases to README.

[hnakamur]

I found CMAKE_LINK_GROUP_USING_RESCAN_SUPPORTED is not defined on macOS even with CMake >= 3.24.
So special handling for macOS must be kept like below:
master...hnakamur:trafficserver:old_cmake_link_group_fallback

[moonchen]

Thanks for finding the workaround with --start-group. That should help if we can't move to 3.24.

As far as macOS, the rescan behavior is included with the included linker. The else() case is there to avoid an error with duplicate symbols.

This current way is messy, but I hope we can remove the circular dependencies soon so none of this hacking is necessary.

[hnakamur]

I've sent a pull request: Link iocore/net/test_net correctly on OSes other than macOS with old CMake (<3.24) by hnakamur · Pull Request #12038 · apache/trafficserver.

What to do with this issue. Should I close it?