reproduce-integration-fail.md

From the root arrow checkout of https://github.com/paleolimbot/arrow plus git switch archery-nanoarrow-integration:

Make sure archery is installed:

pip install -e "dev/archery[all]"

From the csharp/ subdirectory run

dotnet build

From the arrow checkout, clone + build nanoarrow where the default Archery options look for the integration test binary.

git clone https://github.com/paleolimbot/arrow-nanoarrow.git nanoarrow
cd nanoarrow && git switch integration-fixes
mkdir cdata && cd cdata && cmake .. -DNANOARROW_BUILD_INTEGRATION_TESTS=ON && cmake --build .
cd ../..

Run the integration test for exactly one file that is failing

python -m "archery.cli" integration \
    --with-nanoarrow=true \
    --with-csharp=true \
    --run-c-data \
    --match=primitive_zerolength

reproducer.py

"""
From the root arrow checkout of https://github.com/paleolimbot/arrow
plus `git switch archery-nanoarrow-integration`:

Make sure archery is installed:

```
pip install -e "dev/archery[all]"
```

From the csharp/ subdirectory run

```
dotnet build
```

From the arrow checkout, clone + build nanoarrow where the default Archery
options look for the integration test binary.

```
git clone https://github.com/paleolimbot/arrow-nanoarrow.git nanoarrow
cd nanoarrow && git switch integration-fixes
mkdir cdata && cd cdata && cmake .. -DNANOARROW_BUILD_INTEGRATION_TESTS=ON && cmake --build .
cd ../..
```

Run the integration test for exactly one file that is failing

python -m "archery.cli" integration \
    --with-nanoarrow=true \
    --with-csharp=true \
    --run-c-data \
    --match=primitive_zerolength
"""

import nanoarrow as na
from archery.integration import cdata
from archery.integration.tester_cpp import CppTester
from archery.integration.tester_csharp import CSharpTester
from archery.integration.tester_nanoarrow import NanoarrowTester

with open("primitive-empty.json", "w") as f:
    f.write("""{
  "schema": {
    "fields": [
      {"name": "binary_nullable", "type": {"name": "binary"}, "nullable": true, "children": []}
    ]
  },
  "batches": [
    {
      "count": 0,
      "columns": [
        {"name": "binary_nullable", "count": 0, "VALIDITY": [], "OFFSET": [0], "DATA": []}
      ]
    }
  ]
}""")

tester_na = NanoarrowTester()
tester_cs = CSharpTester()

exporter = tester_na.make_c_data_exporter()
importer = tester_cs.make_c_data_importer()

json_path = "primitive-empty.json"
ffi = cdata.ffi()

c_array_ptr = ffi.new("struct ArrowArray*")

with cdata.check_memory_released(exporter, importer):
    exporter.export_batch_from_json(json_path, 0, c_array_ptr)
    importer.import_batch_and_compare_to_json(json_path, 0, c_array_ptr)