Comparison filters on ListNews (PublishedUtc.gte/gt/lte/lt) are unconstructible from outside the gen package

[Americas]

Description

The ListNewsParams struct in rest/gen/client.gen.go exposes comparison filters
for published_utc (and similarly for ticker.gte/gt/lte/lt) as anonymous structs
with a single unexported field:

// rest/gen/client.gen.go
type ListNewsParams struct {
    // ...
    PublishedUtcGte *struct {
        union json.RawMessage
    } `form:"published_utc.gte,omitempty" json:"published_utc.gte,omitempty"`

    PublishedUtcGt  *struct{ union json.RawMessage } `...`
    PublishedUtcLte *struct{ union json.RawMessage } `...`
    PublishedUtcLt  *struct{ union json.RawMessage } `...`
    // ...
}

These fields appear to come from a oneOf<datetime, date> schema in the OpenAPI
spec. oapi-codegen normally emits FromX / AsX / MergeX helpers for union
types, but no such helpers are generated here:

$ grep -E 'FromListNewsParamsPublishedUtcGte|AsListNewsParamsPublishedUtcGte' rest/gen
(no matches)

Why this is a problem

Two compounding issues make these fields unusable from outside the gen package:

1. The union field is unexported. Per the Go spec (Type identity):

   Non-exported field names from different packages are always different.

   So callers cannot construct an equivalent struct literal — struct{ union json.RawMessage }{...} declared elsewhere is a different type and is not assignable to *ListNewsParams.PublishedUtcGte.

2. No exported constructor or setter is generated.

The serialization side of the SDK does work — NewListNewsRequest calls runtime.StyleParamWithLocation on *params.PublishedUtcGte and produces the correct published_utc.gte=... query parameter — but there is no supported way to put a value into the field.

The only workarounds available to consumers are:

• A RequestEditorFn that manually appends published_utc.gte to the query string (bypassing the typed param entirely).
• reflect + unsafe to set the unexported field.

Affected fields include (non-exhaustive):

• ListNewsParams.PublishedUtcGte / Gt / Lte / Lt
• Likely the same pattern on other endpoints that filter by published_utc, timestamp, etc.

Versions

• github.com/massive-com/client-go/v3 v3.1.0 and v3.3.0 (verified both)
• Go 1.26