fix: remove hard requirements on active_support and webmock

[Saup21]

Summary

• active_support was never a declared runtime dependency but pact used blank?/present? in 70+ places, forcing every consumer to pre-require it as a workaround. This PR adds a minimal built-in polyfill (lib/pact/support/blank.rb) loaded early in pact.rb — it is skipped automatically if active_support (or anything else) has already defined these methods, so existing users are unaffected.

• webmock had a missing return in WebmockHelpers.turned_off, causing it to fall through to WebMock::Config even when WebMock was not loaded, crashing with a NameError. Adding the return makes webmock a truly optional integration dependency again.

• pact.gemspec now documents both as optional with a comment explaining the intent.

Motivation

Consumers of this gem were forced to add defensive require statements with inline comments explaining the workarounds. These workarounds have no "remove when X is fixed" marker, so they accumulate silently in downstream codebases. Fixing at the source removes the need for any workaround in consuming code.

Test plan

• Existing RSpec suite passes (bundle exec rspec)
• WebmockHelpers.turned_off { } no longer raises when webmock is not loaded
• blank?/present? behave correctly without active_support loaded
• When active_support is loaded first, its definitions take precedence (polyfill is skipped)

🤖 Generated with Claude Code

[YOU54F]

ci checks didn't kick off for some reason

[YOU54F]

a point of note, the code was originally designed by authors primarily with rails in mind, and for non-rails users like ourselves with the pact_broker and ruby client libraries, they currently require combustion to be loaded on both the consumer and provider side. Some of the changes in this PR are moving towards us not requiring on the consumer side. With the changes recommended below, we eliminate it entirely from the consumer side, but the provider side needs more investigation.

For consumer side,

https://github.com/pact-foundation/pact-ruby/blob/master/example/zoo-app/Gemfile#L10

presence is missing

X_PACT_DEVELOPMENT=true bundle exec rake pact:spec

     NoMethodError:
       undefined method 'presence' for nil
     # /Users/yousaf.nabi/dev/pact-foundation/pact-ruby/lib/pact/matchers/v3/each.rb:13:in 'Pact::Matchers::V3::Each#initialize'

resolved by requiring

require 'active_support/core_ext/object/blank'

We can remove the requirement for combustion gem for non-rails apps

https://github.com/pact-foundation/pact-ruby/blob/master/example/zoo-app/spec/rails_helper.rb

For the provider side

https://github.com/pact-foundation/pact-ruby/blob/master/example/animal-service/Gemfile

changes for webmock working fine now, so webmock is no longer mandatory to be required in the users Gemfile when doing pact verifications.

Without combustion loaded in the provider side project

X_PACT_DEVELOPMENT=true bundle exec rake pact:verify:foobar

we get the following error

NameError:
  uninitialized constant Pact::Provider::ProviderServerRunner::Logger
# /Users/yousaf.nabi/dev/pact-foundation/pact-ruby/lib/pact/provider/provider_server_runner.rb:18:in 'Pact::Provider::ProviderServerRunner#initialize'

Loading combustion gem, with the following helper resolves

https://github.com/pact-foundation/pact-ruby/blob/master/example/animal-service/spec/rails_helper.rb

[YOU54F]

Looks good to me now, thanks!

This PR fixes 1 & 3

Please add a note here to state if testing a non-rails application, to require the combustion gem, add the following helper

require "combustion"

begin
  Combustion.initialize! :action_controller
rescue => e
  warn "💥 Failed to load the pact-ruby: #{e.message}\n#{e.backtrace.join("\n")}"
  exit(1)
end

We should look at sorting out issue 2, as well as addressing #399

Thanks!