Chardata plus

[pp-mo]

Reworking of #6764 for all the changes except the encoding support.
With the intention of adding "encoding dataset", separately developed

[pp-mo]

Status 2026-01-13

Current failures:

TESTFAIL:/integration/netcdf/test_chararrays.py::test_load_encodings[utf-32]
TESTFAIL:/integration/netcdf/test_chararrays.py::test_save_encodings[None]
TESTFAIL:/integration/netcdf/test_chararrays.py::test_save_encodings[utf-8]
TESTFAIL:/integration/netcdf/test_chararrays.py::test_save_encodings[utf-32]
TESTFAIL:/integration/netcdf/test_general.py::TestLazySave::test_lazy_preserved_save
TESTFAIL:/unit/fileformats/nc_load_rules/helpers/test_build_and_add_auxiliary_coordinate.py::TestBoundsVertexDim::test_fastest_varying_vertex_dim__normalise_bounds
TESTFAIL:/unit/fileformats/nc_load_rules/helpers/test_build_and_add_auxiliary_coordinate.py::TestBoundsVertexDim::test_fastest_with_different_dim_names__normalise_bounds
TESTFAIL:/unit/fileformats/nc_load_rules/helpers/test_build_and_add_auxiliary_coordinate.py::TestBoundsVertexDim::test_slowest_varying_vertex_dim__normalise_bounds
TESTFAIL:/unit/fileformats/nc_load_rules/helpers/test_build_and_add_auxiliary_coordinate.py::TestDtype::test_add_offset_float
TESTFAIL:/unit/fileformats/nc_load_rules/helpers/test_build_and_add_auxiliary_coordinate.py::TestDtype::test_scale_factor_add_offset_int
TESTFAIL:/unit/fileformats/nc_load_rules/helpers/test_build_and_add_auxiliary_coordinate.py::TestDtype::test_scale_factor_float
TESTFAIL:/unit/fileformats/nc_load_rules/helpers/test_build_and_add_auxiliary_coordinate.py::TestCoordConstruction::test_aux_coord_construction
TESTFAIL:/unit/fileformats/nc_load_rules/helpers/test_build_and_add_auxiliary_coordinate.py::TestCoordConstruction::test_aux_coord_construction__climatology
TESTFAIL:/unit/fileformats/nc_load_rules/helpers/test_build_and_add_auxiliary_coordinate.py::TestCoordConstruction::test_bad_coord_system
TESTFAIL:/unit/fileformats/nc_load_rules/helpers/test_build_and_add_auxiliary_coordinate.py::TestCoordConstruction::test_not_added
TESTFAIL:/unit/fileformats/nc_load_rules/helpers/test_build_and_add_auxiliary_coordinate.py::TestCoordConstruction::test_with_coord_system
TESTFAIL:/unit/fileformats/nc_load_rules/helpers/test_build_and_add_dimension_coordinate.py::TestCoordConstruction::test_aux_coord_construction
TESTFAIL:/unit/fileformats/nc_load_rules/helpers/test_build_and_add_dimension_coordinate.py::TestCoordConstruction::test_auxcoord_not_added
TESTFAIL:/unit/fileformats/nc_load_rules/helpers/test_build_and_add_dimension_coordinate.py::TestCoordConstruction::test_dimcoord_not_added
TESTFAIL:/unit/fileformats/netcdf/saver/test_Saver.py::Test_write::test_compression
TESTFAIL:/unit/fileformats/netcdf/saver/test_Saver.py::Test_write::test_non_compression__dtype
TESTFAIL:/unit/fileformats/netcdf/saver/test_Saver.py::Test_write::test_non_compression__shape
TESTFAIL:/unit/fileformats/netcdf/saver/test_Saver__lazy.py::Test_write::test_compression
TESTFAIL:/unit/fileformats/netcdf/saver/test_Saver__lazy.py::Test_write::test_non_compression__dtype
TESTFAIL:/unit/fileformats/netcdf/saver/test_Saver__lazy.py::Test_write::test_non_compression__shape
TESTFAIL:/unit/fileformats/netcdf/saver/test_save.py::Test_HdfSaveBug::test_string_dim_varname_collision
...
=== 26 failed, 10584 passed, 54 skipped, 2617 warnings in 595.77s (0:09:55) ====

Compared to the old version:

• we get various errors in test_chararrays (i.e. since we removed all the code to handle non-ascii encodings)
• we LOST the errors :

  TESTFAIL:/unit/fileformats/netcdf/loader/test__get_cf_var_data.py::Test__get_cf_var_data::test_arraytype__100f8_is_real
  TESTFAIL:/unit/fileformats/netcdf/loader/test__get_cf_var_data.py::Test__get_cf_var_data::test_arraytype__1ki2_is_real
  TESTFAIL:/unit/fileformats/netcdf/loader/test__get_cf_var_data.py::Test__get_cf_var_data::test_vltype__1000str_is_real_with_hint
  TESTFAIL:/unit/fileformats/netcdf/loader/test__get_cf_var_data.py::Test__get_cf_var_data::test_vltype__100f8_is_real_with_hint
  TESTFAIL:/unit/fileformats/netcdf/loader/test__get_cf_var_data.py::Test__get_cf_var_data::test_vltype__100str_is_real
  

• we GAINED the error :
  TESTFAIL:/unit/fileformats/netcdf/saver/test_save.py::Test_HdfSaveBug::test_string_dim_varname_collision