Fix `Mime::Type.parse` for HTTP Accept with parameters

Fixes MIME parsing raising errors on valid parameters #51594.

Mime type lookups were updated to handle custom registered types as part of #48397.

This fix the strips out custom media range parameters before falling back to the default type creation.

actionpack/CHANGELOG.md

@@ -1,3 +1,7 @@
+*   Fix `Mime::Type.parse` handling type parameters for HTTP Accept headers.
+
+    *Taylor Chaparro*
+
 *   Fix the error page that is displayed when a view template is missing to account for nested controller paths in the
     suggested correct location for the missing template.
 

actionpack/lib/action_dispatch/http/mime_type.rb

@@ -165,8 +165,11 @@ module Mime
       end
 
       def lookup(string)
+        return LOOKUP[string] if LOOKUP.key?(string)
+
         # fallback to the media-type without parameters if it was not found
-        LOOKUP[string] || LOOKUP[string.split(";", 2)[0]&.rstrip] || Type.new(string)
+        string = string.split(";", 2)[0]&.rstrip
+        LOOKUP[string] || Type.new(string)
       end
 
       def lookup_by_extension(extension)

actionpack/test/dispatch/mime_type_test.rb

@@ -68,6 +68,12 @@ class MimeTypeTest < ActiveSupport::TestCase
     assert_equal expect.map(&:to_s), Mime::Type.parse(accept).map(&:to_s)
   end
 
+  test "parse with q and media type parameters" do
+    accept = "text/xml,application/xhtml+xml,text/yaml; q=0.3,application/xml,text/html; q=0.8,image/png,text/plain; q=0.5,application/pdf,*/*; encoding=UTF-8; q=0.2"
+    expect = [Mime[:html], Mime[:xml], Mime[:png], Mime[:pdf], Mime[:text], Mime[:yaml], "*/*"]
+    assert_equal expect.map(&:to_s), Mime::Type.parse(accept).map(&:to_s)
+  end
+
   test "parse single media range with q" do
     accept = "text/html;q=0.9"
     expect = [Mime[:html]]
@@ -92,6 +98,12 @@ class MimeTypeTest < ActiveSupport::TestCase
     assert_equal expect, Mime::Type.parse(accept)
   end
 
+  test "parse wildcard with arbitrary media type parameters" do
+    accept = '*/*; boundary="simple"'
+    expect = ["*/*"]
+    assert_equal expect, Mime::Type.parse(accept)
+  end
+
   # Accept header send with user HTTP_USER_AGENT: Sunrise/0.42j (Windows XP)
   test "parse broken acceptlines" do
     accept = "text/xml,application/xml,application/xhtml+xml,text/html;q=0.9,text/plain;q=0.8,image/*,,*/*;q=0.5"