[dinwwwh]

Docs only. This adds a sentence to the oapi-codegen bullet in packages/downgrader/README.md.

In 3.0, a nullable $ref or enum parameter becomes oneOf [X, null branch]. oapi-codegen v2.8.2 (-generate types,std-http-server) types that parameter as *struct{ union json.RawMessage }, an anonymous struct with no methods, so code cannot read it. Binding at runtime then either loses the value or rejects it.

I tested this on the real oRPC beta.49 GET doc (g49/gq.mjs, Zod Prio.nullable() with an id and z.enum(['x', 'y']).nullable()), driving the generated handler through httptest:

request	3.0.4 output	3.1.1 input
?prio=5	200, params.Prio == nil	200, prio: 5
?e=x	200, params.E unset	200, e: "x"
header X-E: x	400 "property/values need to be pairs"	200, X-E: "x"
?n=2.5 ({type: number, nullable})	200, n: 2.5	200, n: 2.5

The 3.1 reading types anyOf [$ref, null] as *Prio and anyOf [enum, null] as *AParamsE string. A union of literals with an id (Level) gets dropped in both versions, so it's left out of the table.

I'm not proposing a code change. A nullable enum stays a oneOf with the null branch on purpose, because putting null in the enum breaks other generators, and the allOf + nullable form broke oapi-codegen in an earlier round. Request bodies are fine, since the union unmarshals from JSON.

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_{Comparing claude/project-thread-a8h0xv (678eacc) with main (84f2c48)}

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1. 2 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

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Reviewed changes

• oapi-codegen limitation entry — Adds one sentence to the existing 2.8 bullet in packages/downgrader/README.md, recording that its generated server types a 3.0 oneOf parameter (the shape a nullable $ref or enum becomes) as a union with no accessor, leaving a query parameter unset and rejecting a header parameter with a 400, while its 3.1 reading binds the anyOf to the underlying type.

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