diff --git a/absl/container/inlined_vector_test.cc b/absl/container/inlined_vector_test.cc index 241389aef85..f4bd6da5a70 100644 --- a/absl/container/inlined_vector_test.cc +++ b/absl/container/inlined_vector_test.cc @@ -304,6 +304,33 @@ TEST(UniquePtr, MoveAssign) { } } +// Swapping containers of unique pointers should work fine, with no +// leaks, despite the fact that unique pointers are trivially relocatable but +// not trivially destructible. +TEST(UniquePtr, Swap) { + for (size_t size1 = 0; size1 < 5; ++size1) { + for (size_t size2 = 0; size2 < 5; ++size2) { + absl::InlinedVector, 2> a; + absl::InlinedVector, 2> b; + for (size_t i = 0; i < size1; ++i) { + a.push_back(std::make_unique(i + 10)); + } + for (size_t i = 0; i < size2; ++i) { + b.push_back(std::make_unique(i + 20)); + } + a.swap(b); + ASSERT_THAT(a, SizeIs(size2)); + ASSERT_THAT(b, SizeIs(size1)); + for (size_t i = 0; i < a.size(); ++i) { + ASSERT_THAT(a[i], Pointee(i + 20)); + } + for (size_t i = 0; i < b.size(); ++i) { + ASSERT_THAT(b[i], Pointee(i + 10)); + } + } + } +} + // At the end of this test loop, the elements between [erase_begin, erase_end) // should have reference counts == 0, and all others elements should have // reference counts == 1. diff --git a/absl/container/internal/inlined_vector.h b/absl/container/internal/inlined_vector.h index 0eb9c34ddd5..d7d34f11620 100644 --- a/absl/container/internal/inlined_vector.h +++ b/absl/container/internal/inlined_vector.h @@ -322,14 +322,13 @@ class Storage { // The policy to be used specifically when swapping inlined elements. using SwapInlinedElementsPolicy = absl::conditional_t< - // Fast path: if the value type can be trivially move constructed/assigned - // and destroyed, and we know the allocator doesn't do anything fancy, - // then it's safe for us to simply swap the bytes in the inline storage. - // It's as if we had move-constructed a temporary vector, move-assigned - // one to the other, then move-assigned the first from the temporary. - absl::conjunction>, - absl::is_trivially_move_assignable>, - absl::is_trivially_destructible>, + // Fast path: if the value type can be trivially relocated, and we + // know the allocator doesn't do anything fancy, then it's safe for us + // to simply swap the bytes in the inline storage. It's as if we had + // relocated the first vector's elements into temporary storage, + // relocated the second's elements into the (now-empty) first's, + // and then relocated from temporary storage into the second. + absl::conjunction>, std::is_same>>>::value, MemcpyPolicy, absl::conditional_t::value, ElementwiseSwapPolicy,