Fix Rails 7.1 compatibility.

Rails 7.1 has sped up its internal OutputBuffer implementation (what handles << concatenation in templates),
which we rely on tricking a bit. rails/rails#45614

Then a follow up PR the `to_s` call was moved to after calling `view._run` rails/rails#45756

However, we rely on the return value being a Hash (which I'm not sure how to fix yet).

So since `target!` is the return value of our templates, we can wrap that and ensure `to_s` doesn't actually `to_s`, which Rails 7.1
will call for us.

On Rails < 7.1 we must call the compatibility `unwrap_target!` method ourselves to get our inner Hash return value.

This also adds a Rails version matrix so we can detect these things before release in the future.

.github/workflows/ci.yml

@@ -8,17 +8,27 @@ on:
   pull_request:
 
 jobs:
-  tests:
-    runs-on: ubuntu-latest
-    name: Ruby ${{ matrix.ruby-version }}
+  test:
     strategy:
+      fail-fast: false
       matrix:
+        rails-version:
+          - "7.1"
+          - "6.1"
+          - "main"
         ruby-version:
           - "3.0"
           - "3.2"
 
+    env:
+      RAILS_ENV: test
+      RAILS_VERSION: ${{ matrix.rails-version }}
+
+    name: ${{ format('Test rails@{0} ruby@{1}', matrix.rails-version, matrix.ruby-version) }}
+    runs-on: "ubuntu-latest"
+
     steps:
-    - uses: actions/checkout@v3
+    - uses: actions/checkout@v4
     - name: Set up Ruby
       uses: ruby/setup-ruby@v1
       with:

Gemfile

@@ -12,3 +12,13 @@ gem "sqlite3"
 gem "standard", "~> 1.3"
 
 gem "mocha"
+
+rails_version = ENV.fetch("RAILS_VERSION", "7.0")
+
+rails_constraint = if rails_version == "main"
+  {github: "rails/rails"}
+else
+  "~> #{rails_version}.0"
+end
+
+gem "rails", rails_constraint

Gemfile.lock

@@ -3,7 +3,7 @@ PATH
   specs:
     jbuilder-schema (2.3.1)
       jbuilder
-      rails (>= 5.0.0, < 7.1.0)
+      rails (>= 5.0.0)
 
 GEM
   remote: https://rubygems.org/
@@ -207,6 +207,7 @@ PLATFORMS
 DEPENDENCIES
   jbuilder-schema!
   mocha
+  rails (~> 7.0.8.0)
   rake (~> 13.0)
   sqlite3
   standard (~> 1.3)

jbuilder-schema.gemspec

@@ -34,7 +34,7 @@ Gem::Specification.new do |spec|
   # Uncomment to register a new dependency of your gem
   spec.add_dependency "jbuilder"
 
-  spec.add_dependency "rails", ">= 5.0.0", "< 7.1.0"
+  spec.add_dependency "rails", ">= 5.0.0"
 
   # For more information and examples about making a new gem, check out our
   # guide at: https://bundler.io/guides/creating_gem.html

lib/jbuilder/schema/renderer.rb

@@ -37,7 +37,9 @@ def render(object = nil, title: nil, description: nil, assigns: nil, **options)
     options[:locals].merge! @default_locals if @default_locals
     options[:locals][:__jbuilder_schema_options] = {json: json, object: object, title: title, description: description}
 
-    @view_renderer.render(options)
+    @view_renderer.render(options).then do |result|
+      result.respond_to?(:unwrap_target!) ? result.unwrap_target! : result
+    end
   end
 
   # Thin wrapper around the regular Jbuilder JSON output render, which also parses it into a hash.

lib/jbuilder/schema/template.rb

@@ -54,8 +54,22 @@ def initialize(context, json: nil, **options)
       @ignore_nil = false
     end
 
+    class TargetWrapper
+      def initialize(object)
+        @object = object
+      end
+
+      # Rails 7.1 calls `to_s` on our `target!` (the return value from our templates).
+      # To get around that and let our inner Hash through, we add this override.
+      # `unwrap_target!` is added for backwardscompatibility so we get the inner Hash on Rails < 7.1.
+      def to_s
+        @object
+      end
+      alias unwrap_target! to_s
+    end
+
     def target!
-      schema!
+      TargetWrapper.new(schema!)
     end
 
     def schema!

test/fixtures/gem_loading_script.rb

@@ -6,10 +6,16 @@
 gemfile do
   source "https://rubygems.org"
 
+  gem "activesupport", ENV["RAILS_VERSION"]
+
   gem "jbuilder"
   gem "jbuilder-schema", path: "../jbuilder-schema"
 end
 
+# These aren't loaded automatically on Rails 7.1.
+require "active_support"
+require "active_support/time_with_zone"
+
 user = Struct.new(:id, :name, :email, :created_at, :updated_at).new(1, "John", "john@example.com", Time.now, Time.now)
 
 puts Jbuilder::Schema.renderer(["test/fixtures/app/views/api/v1", "test/fixtures/app/views"]).yaml partial: "api/v1/users/user", object: user

test/jbuilder/schema/gem_loading_test.rb

@@ -2,7 +2,7 @@
 
 class Jbuilder::Schema::GemLoadingTest < ActiveSupport::TestCase
   test "loads when put after jbuilder" do
-    output = `bundle exec ruby test/fixtures/gem_loading_script.rb`
+    output = `RAILS_VERSION="#{ActiveSupport.gem_version}" bundle exec ruby test/fixtures/gem_loading_script.rb`
 
     assert_includes output, "type: object"
     assert_includes output, "properties:\n  id:\n    type: integer"