Filter by null values

[fengelniederhammer]

It should be possible to filter for null valued fields.

I just checked on the Loculus Ebola instance:

For GET requests it seems to work:

GET /sample/details?accessionVersion=LOC_0001D2F.1&ncbi_is_lab_host= yields a result.
Taken from this swagger request:

For POST it does not

POST /sample/details
{
  "accessionVersion": "LOC_0001D2F.1",
  "ncbi_is_lab_host": null
}

yields no result.

POST /sample/details
{
  "accessionVersion": "LOC_0001D2F.1"
}

yields the same result as the GET request.

Expected behavior

• Both GET and POST should return the same results.
• For both methods it should be possible to filter by null. This should be possible for every sequence filter field that LAPIS offers.

[chaoran-chen]

Are you sure that it works with GET? I wasn't aware that we ever implemented support for querying null and I assumed that it is currently not possible with SILO.

[fengelniederhammer]

SILO supports it:

• https://github.com/GenSpectrum/LAPIS-SILO/blob/13c1e0267a39da29084d4767508f3dd6e72a31da/endToEndTests/test/queries/booleanEquals_Or.json#L13
• The GET request almost shows that it works. Modifications confirm that it actually does work with GET.
• I also quickly checked locally.

[fengelniederhammer]

The SILO code is also quite explicit:
https://github.com/GenSpectrum/LAPIS-SILO/blob/13c1e0267a39da29084d4767508f3dd6e72a31da/src/silo/query_engine/filter_expressions/string_equals.cpp#L82-L85

[chaoran-chen]

Ah okay, that's super cool! Then, it certainly would be nice to fix the POST request and make it fully work. Priority-wise, after #754?

[JonasKellerer]

Just a reminder from #755: Null can not be entered on boolean columns in GET requests.