add support for openapi 3.2

[modosc]

(split out from #152 (comment))

i have my attempt at 3.2 support. it's 16 (sorry!) stacked prs here that follow the same pattern as 3.1:

• parse new fields permissively
• add a SpecValidator rule per feature
• add runtime support only where it's simple

what's covered:

• runtime:
  • query / additionalOperations routing
  • case-insensitive method lookup in request_operation
  • discriminator.defaultMapping
  • $ref in content (e.g. into components.mediaTypes)
• parse only:
  • $self
  • itemSchema
  • response summary
• detection only: the rest of the new fields
• deprecation rules:
  • allowEmptyValue
  • xml.attribute / xml.wrapped

left out for now:

• runtime validation of in: querystring
• runtime validation of streaming bodies (itemSchema)
• $self as a base uri for $ref resolution
• cookie params (never validated at runtime, so style: cookie is detection only)

existing 3.0/3.1 docs shouldn't see any behavior change:

• the runtime changes above only apply to docs that declare 3.2+
• specs pin the 3.0/3.1 behavior
• allow_3_2_features: true opts older docs in
• one tiny exception: PathItem#operation(:summary) now returns nil instead of the summary string

there's also a .ruby-version bump, since i couldn't install 3.1.0 locally (arm64 issue).

@takayamaki @geemus what's the best way forward here? do either of you want to look at the changes from the fork first, or should i open these up here?

[takayamaki]

Great work, thank you!

I think opening them here is better, after splitting them like below.

One tip from the 3.1 series: this repository uses squash merge.
So with a linear stack, all the remaining PRs need a rebase after each merge.
For 3.1, I did not use a linear stack.
I had Claude Code make each PR branch directly from master, and I opened two PRs at a time.
I checked that the two PRs merge cleanly in either order.
(For example, when both PRs add a line to the end of the same list, put the new lines in different places, like #200 and #201.)

If you split the changes this way, I may be able to help review them.
Also, the .ruby-version bump is not related to 3.2, so it may be better to leave it out.

[modosc]

Also, the .ruby-version bump is not related to 3.2, so it may be better to leave it out.

i mentioned it here - you cannot build 3.1.0 anymore on newer macs (something in the toolchain prevents it). i tried all of the workarounds mentioned in the linked threads but nothing worked for me.

i'll open the prs here separate from that change but it would be great to get it in so my remote doesn't have to differ.

[modosc]

claude came up with a way to stage these a few at a time - #213 is the top of the tree. i'll keep adding as these are reviewed.