cql3: result_set: remove std::ref from comperator&
Applying std::ref on `RowComparator& cmp` hits the
following compilation error on Fedora 34 with
libstdc++-devel-11.2.1-9.fc34.x86_64
```
FAILED: build/dev/cql3/statements/select_statement.o
clang++ -MD -MT build/dev/cql3/statements/select_statement.o -MF build/dev/cql3/statements/select_statement.o.d -I/home/bhalevy/dev/scylla/seastar/include -I/home/bhalevy/dev/scylla/build/dev/seastar/gen/include -std=gnu++20 -U_FORTIFY_SOURCE -DSEASTAR_SSTRING -Werror=unused-result -fstack-clash-protection -DSEASTAR_API_LEVEL=6 -DSEASTAR_ENABLE_ALLOC_FAILURE_INJECTION -DSEASTAR_SCHEDULING_GROUPS_COUNT=16 -DSEASTAR_TYPE_ERASE_MORE -DFMT_LOCALE -DFMT_SHARED -I/usr/include/p11-kit-1 -DDEVEL -DSEASTAR_ENABLE_ALLOC_FAILURE_INJECTION -DSCYLLA_ENABLE_ERROR_INJECTION -O2 -DSCYLLA_ENABLE_WASMTIME -iquote. -iquote build/dev/gen --std=gnu++20 -ffile-prefix-map=/home/bhalevy/dev/scylla=. -march=westmere -DBOOST_TEST_DYN_LINK -Iabseil -fvisibility=hidden -Wall -Werror -Wno-mismatched-tags -Wno-tautological-compare -Wno-parentheses-equality -Wno-c++11-narrowing -Wno-sometimes-uninitialized -Wno-return-stack-address -Wno-missing-braces -Wno-unused-lambda-capture -Wno-overflow -Wno-noexcept-type -Wno-error=cpp -Wno-ignored-attributes -Wno-overloaded-virtual -Wno-unused-command-line-argument -Wno-defaulted-function-deleted -Wno-redeclared-class-member -Wno-unsupported-friend -Wno-unused-variable -Wno-delete-non-abstract-non-virtual-dtor -Wno-braced-scalar-init -Wno-implicit-int-float-conversion -Wno-delete-abstract-non-virtual-dtor -Wno-uninitialized-const-reference -Wno-psabi -Wno-narrowing -Wno-array-bounds -Wno-nonnull -Wno-error=deprecated-declarations -DXXH_PRIVATE_API -DSEASTAR_TESTING_MAIN -DHAVE_LZ4_COMPRESS_DEFAULT -c -o build/dev/cql3/statements/select_statement.o cql3/statements/select_statement.cc
In file included from cql3/statements/select_statement.cc:14:
In file included from ./cql3/statements/select_statement.hh:16:
In file included from ./cql3/statements/raw/select_statement.hh:16:
In file included from ./cql3/statements/raw/cf_statement.hh:16:
In file included from ./cql3/cf_name.hh:16:
In file included from ./cql3/keyspace_element_name.hh:16:
In file included from /home/bhalevy/dev/scylla/seastar/include/seastar/core/sstring.hh:25:
In file included from /usr/lib/gcc/x86_64-redhat-linux/11/../../../../include/c++/11/algorithm:74:
In file included from /usr/lib/gcc/x86_64-redhat-linux/11/../../../../include/c++/11/pstl/glue_algorithm_defs.h:13:
In file included from /usr/lib/gcc/x86_64-redhat-linux/11/../../../../include/c++/11/functional:58:
/usr/lib/gcc/x86_64-redhat-linux/11/../../../../include/c++/11/bits/refwrap.h:319:40: error: exception specification of 'function<__gnu_cxx::__ops::_Iter_comp_iter<std::reference_wrapper<const std::function<bool (const std::vector<std::optional<seastar::basic_sstring<signed char, unsigned int, 31, false>>> &, const std::vector<std::optional<seastar::basic_sstring<signed char, unsigned int, 31, false>>> &)>>>, void>' uses itself
= decltype(reference_wrapper::_S_fun(std::declval<_Up>()))>
^
/usr/lib/gcc/x86_64-redhat-linux/11/../../../../include/c++/11/bits/refwrap.h:319:40: note: in instantiation of exception specification for 'function<__gnu_cxx::__ops::_Iter_comp_iter<std::reference_wrapper<const std::function<bool (const std::vector<std::optional<seastar::basic_sstring<signed char, unsigned int, 31, false>>> &, const std::vector<std::optional<seastar::basic_sstring<signed char, unsigned int, 31, false>>> &)>>>, void>' requested here
/usr/lib/gcc/x86_64-redhat-linux/11/../../../../include/c++/11/bits/refwrap.h:321:2: note: in instantiation of default argument for 'reference_wrapper<__gnu_cxx::__ops::_Iter_comp_iter<std::reference_wrapper<const std::function<bool (const std::vector<std::optional<seastar::basic_sstring<signed char, unsigned int, 31, false>>> &, const std::vector<std::optional<seastar::basic_sstring<signed char, unsigned int, 31, false>>> &)>>>, void>' required here
reference_wrapper(_Up&& __uref)
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
/usr/lib/gcc/x86_64-redhat-linux/11/../../../../include/c++/11/type_traits:1017:57: note: while substituting deduced template arguments into function template 'reference_wrapper' [with _Up = __gnu_cxx::__ops::_Iter_comp_iter<std::reference_wrapper<const std::function<bool (const std::vector<std::optional<seastar::basic_sstring<signed char, unsigned int, 31, false>>> &, const std::vector<std::optional<seastar::basic_sstring<signed char, unsigned int, 31, false>>> &)>>>, $1 = (no value), $2 = (no value)]
= __bool_constant<__is_nothrow_constructible(_Tp, _Args...)>;
^
/usr/lib/gcc/x86_64-redhat-linux/11/../../../../include/c++/11/type_traits:1023:14: note: in instantiation of template type alias '__is_nothrow_constructible_impl' requested here
: public __is_nothrow_constructible_impl<_Tp, _Args...>::type
^
/usr/lib/gcc/x86_64-redhat-linux/11/../../../../include/c++/11/type_traits:153:14: note: in instantiation of template class 'std::is_nothrow_constructible<__gnu_cxx::__ops::_Iter_comp_iter<std::reference_wrapper<const std::function<bool (const std::vector<std::optional<seastar::basic_sstring<signed char, unsigned int, 31, false>>> &, const std::vector<std::optional<seastar::basic_sstring<signed char, unsigned int, 31, false>>> &)>>>, __gnu_cxx::__ops::_Iter_comp_iter<std::reference_wrapper<const std::function<bool (const std::vector<std::optional<seastar::basic_sstring<signed char, unsigned int, 31, false>>> &, const std::vector<std::optional<seastar::basic_sstring<signed char, unsigned int, 31, false>>> &)>>>>' requested here
: public conditional<_B1::value, _B2, _B1>::type
^
/usr/lib/gcc/x86_64-redhat-linux/11/../../../../include/c++/11/bits/std_function.h:298:11: note: (skipping 8 contexts in backtrace; use -ftemplate-backtrace-limit=0 to see all)
return __and_<typename _Base::_Local_storage,
^
/usr/lib/gcc/x86_64-redhat-linux/11/../../../../include/c++/11/bits/stl_algo.h:1933:13: note: in instantiation of function template specialization 'std::__partial_sort<utils::chunked_vector<std::vector<std::optional<seastar::basic_sstring<signed char, unsigned int, 31, false>>>, 131072>::iterator_type<std::vector<std::optional<seastar::basic_sstring<signed char, unsigned int, 31, false>>>>, __gnu_cxx::__ops::_Iter_comp_iter<std::reference_wrapper<const std::function<bool (const std::vector<std::optional<seastar::basic_sstring<signed char, unsigned int, 31, false>>> &, const std::vector<std::optional<seastar::basic_sstring<signed char, unsigned int, 31, false>>> &)>>>>' requested here
std::__partial_sort(__first, __last, __last, __comp);
^
/usr/lib/gcc/x86_64-redhat-linux/11/../../../../include/c++/11/bits/stl_algo.h:1954:9: note: in instantiation of function template specialization 'std::__introsort_loop<utils::chunked_vector<std::vector<std::optional<seastar::basic_sstring<signed char, unsigned int, 31, false>>>, 131072>::iterator_type<std::vector<std::optional<seastar::basic_sstring<signed char, unsigned int, 31, false>>>>, long, __gnu_cxx::__ops::_Iter_comp_iter<std::reference_wrapper<const std::function<bool (const std::vector<std::optional<seastar::basic_sstring<signed char, unsigned int, 31, false>>> &, const std::vector<std::optional<seastar::basic_sstring<signed char, unsigned int, 31, false>>> &)>>>>' requested here
std::__introsort_loop(__first, __last,
^
/usr/lib/gcc/x86_64-redhat-linux/11/../../../../include/c++/11/bits/stl_algo.h:4875:12: note: in instantiation of function template specialization 'std::__sort<utils::chunked_vector<std::vector<std::optional<seastar::basic_sstring<signed char, unsigned int, 31, false>>>, 131072>::iterator_type<std::vector<std::optional<seastar::basic_sstring<signed char, unsigned int, 31, false>>>>, __gnu_cxx::__ops::_Iter_comp_iter<std::reference_wrapper<const std::function<bool (const std::vector<std::optional<seastar::basic_sstring<signed char, unsigned int, 31, false>>> &, const std::vector<std::optional<seastar::basic_sstring<signed char, unsigned int, 31, false>>> &)>>>>' requested here
std::__sort(__first, __last, __gnu_cxx::__ops::__iter_comp_iter(__comp));
^
./cql3/result_set.hh:168:14: note: in instantiation of function template specialization 'std::sort<utils::chunked_vector<std::vector<std::optional<seastar::basic_sstring<signed char, unsigned int, 31, false>>>, 131072>::iterator_type<std::vector<std::optional<seastar::basic_sstring<signed char, unsigned int, 31, false>>>>, std::reference_wrapper<const std::function<bool (const std::vector<std::optional<seastar::basic_sstring<signed char, unsigned int, 31, false>>> &, const std::vector<std::optional<seastar::basic_sstring<signed char, unsigned int, 31, false>>> &)>>>' requested here
std::sort(_rows.begin(), _rows.end(), std::ref(cmp));
^
cql3/statements/select_statement.cc:773:21: note: in instantiation of function template specialization 'cql3::result_set::sort<std::function<bool (const std::vector<std::optional<seastar::basic_sstring<signed char, unsigned int, 31, false>>> &, const std::vector<std::optional<seastar::basic_sstring<signed char, unsigned int, 31, false>>> &)>>' requested here
rs->sort(_ordering_comparator);
^
1 error generated.
ninja: build stopped: subcommand failed.
```
Fixes #10079.
Signed-off-by: Benny Halevy <bhalevy@scylladb.com>
Message-Id: <20220215071955.316895-3-bhalevy@scylladb.com>
3e20fee070