These are the packages that would be merged, in order:

Calculating dependencies ... done!
Dependency resolution took 3.16 s (backtrack: 6/20).

[ebuild  N     ] dev-build/b2-5.5.3::gentoo  USE="-examples" 1198 KiB
[ebuild  N     ] virtual/fortran-0-r1::gentoo  USE="openmp" 0 KiB
[ebuild  N     ] sci-libs/openblas-0.3.34::gentoo  USE="openmp -cpudetection -index64 -pthread -relapack -test" 24734 KiB
[ebuild  N     ] media-libs/glew-2.2.0-r1:0/2.2::gentoo  USE="-doc -egl-only -static-libs" 817 KiB
[ebuild  N     ] dev-cpp/pystring-1.1.4-r2:0/0.fudge::gentoo  19 KiB
[ebuild  N     ] dev-cpp/yaml-cpp-0.9.0-r1:0/0.9::gentoo  USE="-test" 1032 KiB
[ebuild  N     ] sys-libs/zlib-ng-2.3.3::gentoo  USE="-compat -static-libs -test" CPU_FLAGS_X86="avx2 avx512f pclmul sse2 sse4_1 sse4_2 ssse3 -avx512_vnni -vpclmulqdq" 2391 KiB
[ebuild  N     ] sys-libs/minizip-ng-4.2.1:0/4::gentoo  USE="openssl -compat -lzma -test -zstd" 597 KiB
[ebuild  N     ] dev-libs/boost-1.91.0-r2:0/1.91.0::gentoo  USE="bzip2 context nls python stacktrace zlib -debug -doc -icu -lzma -mpi -numpy -test -test-full -tools -zstd" PYTHON_TARGETS="python3_14 -python3_12 -python3_13" 199785 KiB
[ebuild     U  ] dev-python/installer-1.1.0::gentoo [0.7.0::gentoo] USE="-test -verify-provenance%" PYTHON_TARGETS="python3_14* -pypy3_12% -python3_12 -python3_13* -python3_14t (-python3_15) (-python3_15t) (-pypy3_11%) (-python3_11%) (-python3_13t%)" 924 KiB
[ebuild     U  ] dev-python/gpep517-23::gentoo [19::gentoo] USE="-test" PYTHON_TARGETS="python3_14* -pypy3_12% -python3_12 -python3_13* -python3_14t (-python3_15) (-python3_15t) (-pypy3_11%) (-python3_11%) (-python3_13t%)" 31 KiB
[ebuild     U  ] dev-python/flit-core-4.1.0::gentoo [3.12.0::gentoo] USE="-test -verify-provenance%" PYTHON_TARGETS="python3_14* -pypy3_12% -python3_12 -python3_13* -python3_14t (-python3_15) (-python3_15t) (-pypy3_11%) (-python3_11%) (-python3_13t%)" 54 KiB
[ebuild     U  ] dev-python/packaging-26.3::gentoo [26.0::gentoo] USE="-test -verify-provenance" PYTHON_TARGETS="python3_14* -pypy3_12% -python3_12 -python3_13* -python3_14t (-python3_15) (-python3_15t) (-pypy3_11%) (-python3_11%) (-python3_13t%)" 307 KiB
[ebuild     U  ] dev-python/pyproject-metadata-0.12.1::gentoo [0.11.0::gentoo] USE="-test -verify-provenance" PYTHON_TARGETS="python3_14* -python3_12 -python3_13* -python3_14t (-python3_15) (-python3_15t) (-pypy3_11%) (-python3_11%) (-python3_13t%)" 48 KiB
[ebuild     U  ] dev-python/more-itertools-11.2.1::gentoo [10.8.0::gentoo] USE="-doc" PYTHON_TARGETS="python3_14* -pypy3_12% -python3_12 -python3_13* -python3_14t (-python3_15) (-python3_15t) (-pypy3_11%) (-python3_11%) (-python3_13t%)" 151 KiB
[ebuild     U  ] dev-python/trove-classifiers-2026.9.21.13::gentoo [2026.1.14.14::gentoo] USE="-test -verify-provenance" PYTHON_TARGETS="python3_14* -pypy3_12% -python3_12 -python3_13* -python3_14t (-python3_15) (-python3_15t) (-pypy3_11%) (-python3_11%) (-python3_13t%)" 17 KiB
[ebuild     U  ] dev-python/pathspec-1.1.1::gentoo [1.0.4::gentoo] USE="-verify-provenance" PYTHON_TARGETS="python3_14* -pypy3_12% -python3_12 -python3_13* -python3_14t (-python3_15) (-python3_15t) (-pypy3_11%) (-python3_11%) (-python3_13t%)" 133 KiB
[ebuild     U  ] dev-python/platformdirs-4.13.5::gentoo [4.9.4::gentoo] USE="-test -verify-provenance" PYTHON_TARGETS="python3_14* -pypy3_12% -python3_12 -python3_13* -python3_14t (-python3_15) (-python3_15t) (-pypy3_11%) (-python3_11%) (-python3_13t%)" 61 KiB
[ebuild     U  ] dev-python/wheel-0.48.0::gentoo [0.46.3::gentoo] USE="-test -verify-provenance" PYTHON_TARGETS="python3_14* -pypy3_12% -python3_12 -python3_13* -python3_14t (-python3_15) (-python3_15t) (-pypy3_11%) (-python3_11%) (-python3_13t%)" 65 KiB
[ebuild     U  ] dev-python/jaraco-context-6.1.2::gentoo [6.1.1::gentoo] USE="-test" PYTHON_TARGETS="python3_14* -pypy3_12% -python3_12 -python3_13* -python3_14t (-python3_15) (-python3_15t) (-pypy3_11%) (-python3_11%) (-python3_13t%)" 17 KiB
[ebuild     U  ] dev-python/editables-0.6::gentoo [0.5::gentoo] USE="-test" PYTHON_TARGETS="python3_14* -pypy3_12% -python3_12 -python3_13* -python3_14t (-python3_15) (-python3_15t) (-pypy3_11%) (-python3_11%) (-python3_13t%)" 19 KiB
[ebuild  N     ] dev-python/tomlkit-0.15.2::gentoo  USE="-test" PYTHON_TARGETS="python3_14 -pypy3_12 -python3_12 -python3_13 -python3_14t (-python3_15) (-python3_15t)" 187 KiB
[ebuild     U  ] dev-python/jaraco-functools-4.6.0::gentoo [4.4.0::gentoo] USE="-test" PYTHON_TARGETS="python3_14* -pypy3_12% -python3_12 -python3_13* -python3_14t (-python3_15) (-python3_15t) (-pypy3_11%) (-python3_11%) (-python3_13t%)" 21 KiB
[ebuild  N     ] dev-python/meson-python-0.22.1::gentoo  USE="-test" PYTHON_TARGETS="python3_14 -python3_12 -python3_13 (-python3_15)" 111 KiB
[ebuild     U  ] dev-python/jaraco-text-4.3.0::gentoo [4.2.0::gentoo] USE="-test" PYTHON_TARGETS="python3_14* -pypy3_12% -python3_12 -python3_13* -python3_14t (-python3_15) (-python3_15t) (-pypy3_11%) (-python3_11%) (-python3_13t%)" 21 KiB
[ebuild     U  ] dev-python/setuptools-84.0.0::gentoo [81.0.0::gentoo] USE="-test" PYTHON_TARGETS="python3_14* -pypy3_12% -python3_12 -python3_13* -python3_14t (-python3_15) (-python3_15t) (-pypy3_11%) (-python3_11%) (-python3_13t%)" 1142 KiB
[ebuild  N     ] dev-python/vcs-versioning-2.6.0::gentoo  USE="-test -verify-provenance" PYTHON_TARGETS="python3_14 -pypy3_12 -python3_12 -python3_13 -python3_14t (-python3_15) (-python3_15t)" 163 KiB
[ebuild     U  ] dev-python/setuptools-scm-10.3.4::gentoo [9.2.2::gentoo] USE="-test -verify-provenance" PYTHON_TARGETS="python3_14* -pypy3_12% -python3_12 -python3_13* -python3_14t (-python3_15) (-python3_15t) (-pypy3_11%) (-python3_11%) (-python3_13t%)" 77 KiB
[ebuild     U  ] dev-python/cython-3.3.0::gentoo [3.2.4::gentoo] USE="-debug -test -test-full (-doc%)" PYTHON_TARGETS="python3_14* -python3_12 -python3_13* -python3_14t (-python3_15) (-python3_15t) (-pypy3_11%) (-python3_11%) (-python3_13t%)" 3641 KiB
[ebuild     U  ] dev-python/pluggy-1.7.0::gentoo [1.6.0::gentoo] USE="-test -verify-provenance%" PYTHON_TARGETS="python3_14* -pypy3_12% -python3_12 -python3_13* -python3_14t (-python3_15) (-python3_15t) (-pypy3_11%) (-python3_11%) (-python3_13t%)" 121 KiB
[ebuild     U  ] dev-python/hatchling-1.32.4::gentoo [1.29.0::gentoo] USE="-test" PYTHON_TARGETS="python3_14* -pypy3_12% -python3_12 -python3_13* -python3_14t (-python3_15) (-python3_15t) (-pypy3_11%) (-python3_11%) (-python3_13t%)" 5239 KiB
[ebuild   R    ] dev-python/hatch-vcs-0.5.0::gentoo  USE="-test" PYTHON_TARGETS="python3_14* -pypy3_12% -python3_12 -python3_13* -python3_14t (-python3_15) (-python3_15t) (-pypy3_11%) (-python3_11%) (-python3_13t%)" 12 KiB
[ebuild     U  ] dev-python/scikit-build-core-1.1.1::gentoo [0.12.2::gentoo] USE="-test -verify-provenance" PYTHON_TARGETS="python3_14* -python3_12 -python3_13* (-python3_15) (-pypy3_11%) (-python3_11%)" 505 KiB
[ebuild     U  ] dev-python/pybind11-3.1.0::gentoo [3.0.2::gentoo] USE="-test" PYTHON_TARGETS="python3_14* -python3_12 -python3_13* (-python3_15) (-pypy3_11%) (-python3_11%)" 962 KiB
[ebuild  N     ] sci-libs/lapack-3.12.1-r2::gentoo  USE="deprecated flexiblas lapacke -doc -eselect-ldso -index64 -test" 7879 KiB
[ebuild  N     ] sci-libs/flexiblas-3.5.0::gentoo  USE="openblas openmp system-blas -blis -index64 -mkl -tbb -test" 80741 KiB
[ebuild  N     ] sci-libs/blas-lapack-aux-wrapper-6::gentoo  USE="-index64 -test" 10 KiB
[ebuild  N     ] virtual/cblas-3.8-r1::gentoo  USE="flexiblas -eselect-ldso -index64" 0 KiB
[ebuild  N     ] virtual/lapack-3.10-r1::gentoo  USE="flexiblas -eselect-ldso -index64" 0 KiB
[ebuild  N     ] dev-python/numpy-2.5.4:0/2::gentoo  USE="cpudetection lapack (-big-endian) -debug (-index64) -test -verify-provenance" CPU_FLAGS_X86="avx2 avx512bw avx512dq avx512vl sse4_2 -avx512_bf16 -avx512_bitalg -avx512_fp16 -avx512_vbmi2" PYTHON_TARGETS="python3_14 -python3_12 -python3_13 (-python3_15)" 20378 KiB
[ebuild  N     ] dev-libs/imath-3.1.12-r1:3/29::gentoo  USE="python -doc -large-stack -test" PYTHON_SINGLE_TARGET="python3_14 -python3_12 -python3_13" 591 KiB
[ebuild  N     ] media-libs/opencolorio-2.4.2:0/2.4::gentoo  USE="opengl python -apps -doc -test" CPU_FLAGS_X86="avx avx2 avx512f f16c sse2 sse3 sse4_1 sse4_2 ssse3" PYTHON_SINGLE_TARGET="python3_14 -python3_12 -python3_13" 11132 KiB

Total: 42 packages (21 upgrades, 20 new, 1 reinstall), Size of downloads: 365309 KiB

!!! Multiple package instances within a single package slot have been pulled
!!! into the dependency graph, resulting in a slot conflict:

dev-python/pathspec:0

  (dev-python/pathspec-1.1.1:0/0::gentoo, ebuild scheduled for merge) USE="-verify-provenance" PYTHON_TARGETS="python3_14 -pypy3_12 -python3_12 -python3_13 -python3_14t (-python3_15) (-python3_15t)" pulled in by
    >=dev-python/pathspec-0.12.0[python_targets_python3_12(-)?,python_targets_python3_13(-)?,python_targets_python3_14(-)?,python_targets_python3_15(-)?] required by (dev-python/scikit-build-core-1.1.1:0/0::gentoo, ebuild scheduled for merge) USE="-test -verify-provenance" PYTHON_TARGETS="python3_14 -python3_12 -python3_13 (-python3_15)"
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      
    >=dev-python/pathspec-0.10.1[python_targets_pypy3_12(-)?,python_targets_python3_12(-)?,python_targets_python3_13(-)?,python_targets_python3_14t(-)?,python_targets_python3_14(-)?,python_targets_python3_15t(-)?,python_targets_python3_15(-)?] required by (dev-python/hatchling-1.32.4:0/0::gentoo, ebuild scheduled for merge) USE="-test" PYTHON_TARGETS="python3_14 -pypy3_12 -python3_12 -python3_13 -python3_14t (-python3_15) (-python3_15t)"
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  

  (dev-python/pathspec-1.0.4:0/0::gentoo, installed) USE="-verify-provenance" PYTHON_TARGETS="python3_13 -pypy3_11 -python3_11 -python3_12 -python3_13t -python3_14 -python3_14t" pulled in by
    >=dev-python/pathspec-0.9.0[python_targets_python3_13(-)] required by (dev-python/mypy-1.19.1:0/0::gentoo, installed) USE="-debug (-native-extensions) -test" PYTHON_TARGETS="python3_13 -python3_11 -python3_12 -python3_14"
                                                                                                                                                                                                                                                                                                                                                                                       


It may be possible to solve this problem by using package.mask to
prevent one of those packages from being selected. However, it is also
possible that conflicting dependencies exist such that they are
impossible to satisfy simultaneously.  If such a conflict exists in
the dependencies of two different packages, then those packages can
not be installed simultaneously. You may want to try a larger value of
the --backtrack option, such as --backtrack=30, in order to see if
that will solve this conflict automatically.

For more information, see MASKED PACKAGES section in the emerge man
page or refer to the Gentoo Handbook.