pyarrow-core library uses default visibility instead of hidden

[WillAyd]

Solution to issue cannot be found in the documentation.

• I checked the documentation.

Issue

It looks like the pyarrow-core library exposes symbols that are not explicitly exported by Arrow:

$ nm -CD libarrow.so | grep TemporalScalar
00000000002e3e20 t arrow::TemporalScalar<arrow::Date32Type>::~TemporalScalar()
00000000002e3440 t arrow::TemporalScalar<arrow::Date32Type>::~TemporalScalar()
00000000002e3440 t arrow::TemporalScalar<arrow::Date32Type>::~TemporalScalar()
00000000002e4320 t arrow::TemporalScalar<arrow::Date64Type>::~TemporalScalar()
00000000002e30c0 t arrow::TemporalScalar<arrow::Date64Type>::~TemporalScalar()
...

Setting the CXXFLAG -fvisibility-hidden should get rid of these and help shave off some package size (locally I saw about a 5% reduction)

Installed packages

pyarrow-core              16.1.0          py312h5429d62_1_cpu    conda-forge

Environment info

active environment : scratchpad
    active env location : /home/willayd/mambaforge/envs/scratchpad
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                          /home/willayd/.condarc
          conda version : 23.3.1
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                          __glibc=2.35=0
                          __linux=6.8.0=0
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[h-vetinari]

It looks like the pyarrow-core library exposes symbols that are not explicitly exported by Arrow:

I'm not sure I understand what you mean. Let's distinguish between libarrow the library and pyarrow-core the python bindings that build on the library.

You show that libarrow contains some symbols that could apparently be hidden - presumably they are not being used by pyarrow-core then? If we're on the same page w.r.t. that, great!

[WillAyd]

Yea sorry - should have been clearer that I was talking about libarrow. The more I look at this I think there are a few gaps upstream in Arrow - need to investigate further

[WillAyd]

ref apache/arrow#41872