abseil
signed/unsigned compare in btree.h
Describe the bug
Since the enum containing kNodeValues was changed to be explicitly uint32_t, there is now a signed/unsigned comparison:
external/abseil/absl/container/internal/btree.h:2439:19: error: comparison of integer expressions of different signedness: 'int' and 'unsigned int' [-Werror=sign-compare] 2439 | if (max_count < kNodeValues) { | ~~~~~~~~~~^~~~~~~~~~~~~
Steps to reproduce the bug
Compile revision c6b3f2cf583d8fec124f9d70a172b513363506fe with sign comparison warnings turned on
What version of Abseil are you using? HEAD (c6b3f2cf583d8fec124f9d70a172b513363506fe and later)
What operating system and version are you using Linux (RHEL 6)
What compiler and version are you using? gcc 9.1.0 clang 8.0.1 clang 9.0.0
What build system are you using? cmake 3.15.0
Additional context
Unfortunately, there are more issues, my build system just stopped after the first failure:
external/abseil/absl/container/internal/btree.h:2252:45: fatal error: comparison of integers of different signs: 'int' and
'absl::container_internal::btree<absl::container_internal::set_params<StringType, StringCmp, std::__1::allocator<StringType >, 256, false> >::(anonymous enum at <external/abseil/absl/container/internal/btree.h>:1052:3)' [-Wsign-compare]
(1 + (insert_position < kNodeValues));
I attempted to fix so I could provide all the spots that need fixing, but the int here is set from iterator->position, which is purposefully signed, as it uses -1 as a special value for invalid positions:
1006 // The position within the node of the tree the iterator is pointing at.
1007 // NOTE: this is an int rather than a field_type because iterators can point
1008 // to invalid positions (such as -1) in certain circumstances.
1009 int position;
I'm not sure what your preferred solution here would be.
I'm seeing the same thing. It goes on to complain about similar things:
[...]abseil/absl/container/internal/btree.h:2292:37: error: comparison of integers of different signs: 'int' and 'absl::container_internal::btree<absl::container_internal::map_params<const MY_TYPE *, float, std::__1::less<const MY_TYPE *>, std::__1::allocator<std::__1::pair<const MY_TYPE *const, float> >, 256, false> >::(anonymous enum at [...]abseil/absl/container/internal/btree.h:1056:3)' [-Werror,-Wsign-compare]
left->count() + to_move < kNodeValues) {
~~~~~~~~~~~~~~~~~~~~~~~ ^ ~~~~~~~~~~~
where kNodeValues is an enum, to_move is int and so an int. I think it should just be static_cast<int>(kNodeValues) in place of kNodeValues.
