Incorrect generation of free-form objects

[mxk]

OpenAPI Guide states that additionalProperties: true is the default when a schema consists of just type: object, but the generated code ends up with a struct{} type unless additionalProperties: true is specified.

What version of ogen are you using?

v1.0.1-0.20240411144324-e1628ac9f35f

Can this issue be reproduced with the latest version?

Yes

What did you do?

Changed schema from:

"schema": {
  "type": "object"
}

to:

"schema": {
  "type": "object"
  "additionalProperties": true
}

What did you expect to see?

Generated code should be the same.

What did you see instead?

Without additionalProperties:

type MyApiReq struct{}

With additionalProperties:

type MyApiReq map[string]jx.Raw

[dstubbersfield]

Bump. I got stung by this one too using latest OGEN, would be great to see a fix.

[tdakkota]

Current validator/decoder behavior matches expected by JSON Schema.

ogen generates AdditionalProps only if additionalProperties is defined explicitly.
Majority of schemas does not define additionalProperties and probably majority of users do not need them, so current behavior seems more reasonable for me.

#1246 fixes this issue in slighty different way: AdditionalProps would be added implicitly only if properties and patternProperties are not defined, but I still not convinced that any change is required.

@ernado Thoughts?

[ernado]

@tdakkota

Let's generate AdditionalProps for type: object schema, the struct{} is pretty useless.
If #1246 achieves this, it is LGTM.

Also let's keep our default unchanged (do not generate AdditionalProps by default in other cases). If this will be a problem for someone, we can introduce a configuration option.