Revisit Grape's middlewares default options

[ericproulx]

See copilot's comment but it should:

• reduce Hash allocations since default_options have been replaced by frozen constants
• reduce a little bit default_options size since nil values have been removed in favor of keeping actual default.
• add clarity about the default options per middleware

[Copilot]

Pull Request Overview

This PR revisits how default options are handled in Grape’s middleware by updating the option merging strategy and shifting from method‐based defaults to constant-based defaults, while also updating the initialization across several middlewares to use keyword arguments.

• Updated middleware initializations to use keyword arguments (double-splat)
• Replaced default_options methods with DEFAULT_OPTIONS constants where applicable
• Removed the Helpers module from lib/grape/middleware/helpers.rb

Reviewed Changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
spec/grape/middleware/versioner/*_spec.rb	Updated subject initializations to use keyword arguments
spec/grape/middleware/formatter_spec.rb	Updated formatter configuration assignment to overwrite the formatters hash entirely
spec/grape/middleware/exception_spec.rb & error_spec.rb	Updated Error middleware to use keyword arguments
spec/grape/middleware/base_spec.rb	Updated default options test to verify constant DEFAULT_OPTIONS usage
lib/grape/middleware/versioner/base.rb	Replaced method-based default options with a DEFAULT_OPTIONS constant
lib/grape/middleware/helpers.rb	Removed the now-unused Helpers module
lib/grape/middleware/formatter.rb	Replaced default_options method with a DEFAULT_OPTIONS constant with a simplified configuration
lib/grape/middleware/error.rb	Updated Error middleware to use keyword arguments and constant DEFAULT_OPTIONS
lib/grape/middleware/base.rb	Adjusted initialization to merge default options via a helper method
lib/grape/middleware/auth/base.rb	Updated Auth middleware initialization and streamlined the _call method logic

Comments suppressed due to low confidence (2)

lib/grape/middleware/formatter.rb:6

• Removing the default empty initializations for 'formatters' and 'parsers' from the DEFAULT_OPTIONS may lead to issues if downstream code relies on their existence. Consider retaining these keys with empty hashes or ensuring downstream code handles their absence.

DEFAULT_OPTIONS = { default_format: :txt }.freeze

spec/grape/middleware/formatter_spec.rb:239

• Replacing the in-place update of the formatters hash with a full assignment might remove other formatters previously set. Please confirm that this behavior is intentional and that any dependent code is adjusted accordingly.

subject.options[:formatters] = { json: ->(_obj, _env) { 'CUSTOM JSON FORMAT' } }

[dblock]

The caller's hash should be left alone even if internal.

[ericproulx]

@dblock is changing Grape::Middleware::Base signature like I did considered has a breaking change ?

[dblock]

@dblock is changing Grape::Middleware::Base signature like I did considered has a breaking change ?

You know, I think it may be, since we do mention Base in at least one example in README.md. But I don't think we mention the initializer. WDYT?

[ericproulx]

@dblock is changing Grape::Middleware::Base signature like I did considered has a breaking change ?

You know, I think it may be, since we do mention Base in at least one example in README.md. But I don't think we mention the initializer. WDYT?

There's a least an upgrading notes and I think its sufficient.