Revert PR #2577: Restore support for in endpoint blocks

Author: ericproulx

CHANGELOG.md

@@ -12,6 +12,7 @@
 #### Fixes
 
 * [#2633](https://github.com/ruby-grape/grape/pull/2633): Fix cascade reading - [@ericproulx](https://github.com/ericproulx).
+* [#2641](https://github.com/ruby-grape/grape/pull/2641): Revert PR #2577 - Restore support for `return` in endpoint blocks - [@ericproulx](https://github.com/ericproulx).
 * Your contribution here.
 
 ### 3.0.1 (2025-11-24)

lib/grape/endpoint.rb

@@ -32,6 +32,13 @@ def run_before_each(endpoint)
         superclass.run_before_each(endpoint) unless self == Endpoint
         before_each.each { |blk| blk.try(:call, endpoint) }
       end
+
+      def block_to_unbound_method(block)
+        define_method :temp_unbound_method, block
+        method = instance_method(:temp_unbound_method)
+        remove_method :temp_unbound_method
+        method
+      end
     end
 
     # Create a new endpoint.
@@ -70,7 +77,7 @@ def initialize(new_settings, **options, &block)
       @status = nil
       @stream = nil
       @body = nil
-      @source = block
+      @source = self.class.block_to_unbound_method(block) if block
     end
 
     # Update our settings from a given set of stackable parameters. Used when
@@ -188,10 +195,7 @@ def execute
       return unless @source
 
       ActiveSupport::Notifications.instrument('endpoint_render.grape', endpoint: self) do
-        instance_exec(&@source)
-      rescue LocalJumpError => e
-        Grape.deprecator.warn 'Using `return` in an endpoint has been deprecated. Use `next` instead.'
-        return e.exit_value
+        @source.bind_call(self)
       end
     end
 

spec/grape/endpoint_spec.rb

@@ -762,28 +762,12 @@ def memoized
     expect(last_response.body).to eq('yo')
   end
 
-  context 'when `return`' do
-    it 'calls deprecator' do
+  context 'when calling return' do
+    it 'does not raise a LocalJumpError' do
       subject.get('/home') do
         return 'Hello'
       end
 
-      expect(Grape.deprecator).to receive(:warn).with('Using `return` in an endpoint has been deprecated. Use `next` instead.')
-
-      get '/home'
-      expect(last_response.status).to eq(200)
-      expect(last_response.body).to eq('Hello')
-    end
-  end
-
-  context 'when `next`' do
-    it 'does not call deprecator' do
-      subject.get('/home') do
-        next 'Hello'
-      end
-
-      expect(Grape.deprecator).not_to receive(:warn)
-
       get '/home'
       expect(last_response.status).to eq(200)
       expect(last_response.body).to eq('Hello')