When using Fiona, DBF missing headers when no records provided

Question

I'm creating a Esri Shapefile using Fiona. If I don't add any records, the dbf created by Fiona does not include the headers defined by the schema. My customers claim that results in an invalid shapefile. Is there a configuration option to include headers even with no records? I can't find anything in the documentation. Using Fiona 1.8.

This is where the file is opened:

self.__sink = fiona.open(
    self.__path,
    mode='w',
    driver='ESRI Shapefile',
    schema=self.SCHEMA,
    layer=self.__path.name,
    crs='EPSG:4326',
    encoding='utf-8'
)

This is within a method that is called for every instance of a feature. If there are no features, this is never called, and no headers are written.

...
record = {
    'geometry': geojson,
    'properties': {
        ...
    }
}

# Ensure exclusive access with lock
async with self.__write_lock:
    assert self.__sink is not None
    self.__sink.write(record)
    ...

Then the obvious close:

self.__sink.close()
self.__sink = None

Here's the line in Fiona that adds the fields. From how I read it, this should happen irregardless of adding records.

https://github.com/Toblerity/Fiona/blob/1.8.20/fiona/ogrext.pyx#L1221 exc_wrap_int(OGR_L_CreateField(self.cogr_layer, cogr_fielddefn, 1))

I enabled DEBUG logs for Fiona and it appears to be creating the fields

...
[2021-12-06 11:19:17] [DEBUG] [82320] Begin creating field: 'URL' value: 'str:254' [fiona.ogrext] (collection.py:165)
[2021-12-06 11:19:17] [DEBUG] [82320] Field format parsing, value: 'str', fmt: '254' [fiona.ogrext] (collection.py:165)
[2021-12-06 11:19:17] [DEBUG] [82320] End creating field 'URL' [fiona.ogrext] (collection.py:165)

Answer 1

There was a bug that prevented the application from calling the close method on the Fiona object...I think to a point that everything stopped. With that that, Fiona did not have the opportunity to write the headers even without records. With the bug fixed, Fiona correctly writes the headers even without records.