--dump-schema does not dump media handlers

[wolfgangwalther]

Environment

• PostgreSQL version: 16
• PostgREST version: 12.1 (development)
• Operating system: Linux

Description of issue

While trying to debug another possible regression in the current development version, I wanted to see the media handlers via --dump-schema.

(Edit: The following commands only work after 4a796e0)

Running postgrest-with-postgresql-16 -f test/spec/fixtures/load.sql postgrest-run responds with:

...
Schema cache loaded 264 Relations, 221 Relationships, 141 Functions, 15 Domain Representations, 45 Media Type Handlers

Nice!

But, postgrest-with-postgresql-16 -f test/spec/fixtures/load.sql postgrest-run --dump-schema | jq '.dbMediaHandlers' then gives me:

[]

Something is broken there.

In fact, counting the array items of the json response:

{
  "dbMediaHandlers": 0,
  "dbRelationships": 221,
  "dbRepresentations": 15,
  "dbRoutines": 141,
  "dbTables": 264,
  "dbTimezones": 0
}

Not sure if timezones is broken as well?

[wolfgangwalther]

This seems to be the case ever since 82b3834 introduced this line of code:

    , "dbMediaHandlers"   .= JSON.emptyArray

We have the same for timezones:

https://github.com/PostgREST/postgrest/blob/4a796e0758ff1a0bd2795a6bcffa6699e55ae43b/src/PostgREST/SchemaCache.hs#L94C1-L95C45

Why?

[steve-chavez]

, "dbMediaHandlers"   .= JSON.emptyArray

Ah, my bad. I forgot to mark that as TODO. It should be filled.

We have the same for timezones:

I recall this one was on purpose, to not expose it via OpenAPI. But on second thought, would it makes sense to expose it? I guess we could list all Prefer: timezone=xx/yy values but it would be a long list.. not sure.

[wolfgangwalther]

I recall this one was on purpose, to not expose it via OpenAPI. But on second thought, would it makes sense to expose it? I guess we could list all Prefer: timezone=xx/yy values but it would be a long list.. not sure.

This is only about dumping the schema cache, not about openapi. #3238 dumps it now, too - but that doesn't mean it needs to go anywhere else, right?