Update `follow_redirect!` to reuse same HTTP verb for 308 redirections.

actionpack/CHANGELOG.md

@@ -1,3 +1,8 @@
+*   Fix `follow_redirect!` to follow redirection with same HTTP verb when following
+    a 308 redirection.
+
+    *Alan Tan*
+
 *   When multiple domains are specified for a cookie, a domain will now be
     chosen only if it is equal to or is a superdomain of the request host.
 

actionpack/lib/action_dispatch/testing/integration.rb

@@ -54,16 +54,21 @@ module ActionDispatch
 
       # Follow a single redirect response. If the last response was not a
       # redirect, an exception will be raised. Otherwise, the redirect is
-      # performed on the location header. If the redirection is a 307 redirect,
+      # performed on the location header. If the redirection is a 307 or 308 redirect,
       # the same HTTP verb will be used when redirecting, otherwise a GET request
       # will be performed. Any arguments are passed to the
       # underlying request.
       def follow_redirect!(**args)
         raise "not a redirect! #{status} #{status_message}" unless redirect?
 
-        method = response.status == 307 ? request.method.downcase : :get
-        public_send(method, response.location, **args)
+        method =
+          if [307, 308].include?(response.status)
+            request.method.downcase
+          else
+            :get
+          end
 
+        public_send(method, response.location, **args)
         status
       end
     end

actionpack/test/controller/integration_test.rb

@@ -235,6 +235,10 @@ class IntegrationProcessTest < ActionDispatch::IntegrationTest
       redirect_to action_url("post"), status: 307
     end
 
+    def redirect_308
+      redirect_to action_url("post"), status: 308
+    end
+
     def remove_header
       response.headers.delete params[:header]
       head :ok, "c" => "3"
@@ -368,6 +372,15 @@ class IntegrationProcessTest < ActionDispatch::IntegrationTest
     end
   end
 
+  def test_308_redirect_uses_the_same_http_verb
+    with_test_route_set do
+      post "/redirect_308"
+      assert_equal 308, status
+      follow_redirect!
+      assert_equal "POST", request.method
+    end
+  end
+
   def test_redirect_reset_html_document
     with_test_route_set do
       get "/redirect"