Fix respond_to?(:each) with Rack::Lint with streaming bodies.

CHANGELOG.md

@@ -7,6 +7,7 @@ All notable changes to this project will be documented in this file. For info on
 ### Fixed
 
 - `MethodOverride` does not look for an override if a request does not include form/parseable data.
+- `Rack::Lint::Wrapper` correctly handles `respond_to?` with `to_ary`, `each`, `call` and `to_path`, forwarding to the body. ([#1981](https://github.com/rack/rack/pull/1981), [@ioquatix])
 
 ## [3.0.0] - 2022-09-06
 

lib/rack/lint.rb

@@ -817,8 +817,14 @@ def each
         verify_to_path
       end
 
+      BODY_METHODS = {to_ary: true, each: true, call: true, to_path: true}
+
+      def to_path
+        @body.to_path
+      end
+
       def respond_to?(name, *)
-        if name == :to_ary
+        if BODY_METHODS.key?(name)
           @body.respond_to?(name)
         else
           super

test/spec_lint.rb

@@ -33,7 +33,6 @@ def env(*args)
     lambda { Rack::Lint.new(nil).call({}.freeze) }.must_raise(Rack::Lint::LintError).
       message.must_match(/env should not be frozen, but is/)
 
-
     lambda {
       e = env
       e.delete("REQUEST_METHOD")
@@ -473,6 +472,17 @@ def obj.each; end
       message.must_match(/content-length header was 1, but should be 0/)
   end
 
+  it "responds to to_path" do
+    body = Object.new
+    def body.each; end
+    def body.to_path; __FILE__ end
+    app = lambda { |env| [200, {}, body] }
+
+    status, headers, body = Rack::Lint.new(app).call(env({}))
+    body.must_respond_to(:to_path)
+    body.to_path.must_equal __FILE__
+  end
+
   it "notice body errors" do
     lambda {
       body = Rack::Lint.new(lambda { |env|