Is type: string, format: binary considered "invalid" in 3.1, or is it "deprecated"?

[Youssef1313]

In 3.1+, how should tooling treat type: string, format: binary?

It's unclear to me from https://spec.openapis.org/oas/v3.1.1.html#migrating-binary-descriptions-from-oas-3-0 whether the representation for OAS < 3.1 is now completely wrong for 3.1+ to represent binary formats, or is it just deprecated and not recommended but should still work?

[handrews]

I would not expect it to work in 3.1+ tooling as there is no requirement for it to do so. Some tools might support it, but it's not interoperable (you cannot count on support across the whole ecosystem).

[karenetheridge]

How did it work in 3.0? That is -- what difference did it make when format: binary was present, vs not present?

[handrews]

The main difficulty is actually the "type": "string" part, as binary data is not actually a JSON string. This is why it got changed in 3.1, where you simply use an empty {} or true schema and set the binary media type wherever it is appropriate (the key for the Media Type Object, or the contentType field in the Encoding Object).

Otherwise, "format": "binary" would just get ignored as an unknown/unsupported format which would more-or-less have the same effect. Presumably, no one in 3.0 was actually passing binary data to JSON Schema implementations anyway. But the "type": "string" made it look like you could.

[handrews]

(@karenetheridge I know you know this, but for the benefit of others reading)