Routes inside constraints block don't respect format constraints

[waratuman]

Problem

When wrapping standard_resources in a constraints format: :json block, the format constraint is not enforced. Requests without a .json extension (e.g. GET /transactions) still match the route and hit the controller, resulting in a StandardAPI::ParameterMissing error because required params like limit are missing.

# Expected: /transactions should NOT match, /transactions.json should match
constraints format: :json do
  standard_resources :transactions
end

Workaround

Using a lambda constraint works:

constraints(->(req) { req.format.json? }) do
  standard_resources :transactions
end

Expected Behavior

constraints format: :json should restrict standard_resources routes to only match when the format segment is json, consistent with how resources behaves when wrapped in the same block.

Context

This matters for SPAs where bare paths like /transactions should fall through to a catch-all route serving the frontend, while /transactions.json should hit the API controller.