Fix marking of custom routes for Journey

The Mapper build_path method marks routes where path parameters are part
of a path segment as custom routes by altering the regular expression, e.g:

    get '/foo-:bar', to: 'foo#bar'

There were some edge cases where certain constructs weren't being picked
up and this commit fixes those.

Fixes #23069.

1 files changed, 63 insertions, 0 deletions

diff --git a/actionpack/test/dispatch/routing_test.rb b/actionpack/test/dispatch/routing_test.rb
index 62d65ec5c0..5ead9357ae 100644
--- a/actionpack/test/dispatch/routing_test.rb
+++ b/actionpack/test/dispatch/routing_test.rb
@@ -4654,3 +4654,66 @@ class TestErrorsInController < ActionDispatch::IntegrationTest
     assert_equal 404, response.status
   end
 end
+
+class TestPartialDynamicPathSegments < ActionDispatch::IntegrationTest
+  Routes = ActionDispatch::Routing::RouteSet.new
+  Routes.draw do
+    ok = lambda { |env| [200, { 'Content-Type' => 'text/plain' }, []] }
+
+    get '/songs/song-:song', to: ok
+    get '/songs/:song-song', to: ok
+    get '/:artist/song-:song', to: ok
+    get '/:artist/:song-song', to: ok
+
+    get '/optional/songs(/song-:song)', to: ok
+    get '/optional/songs(/:song-song)', to: ok
+    get '/optional/:artist(/song-:song)', to: ok
+    get '/optional/:artist(/:song-song)', to: ok
+  end
+
+  APP = build_app Routes
+
+  def app
+    APP
+  end
+
+  def test_paths_with_partial_dynamic_segments_are_recognised
+    get '/david-bowie/changes-song'
+    assert_equal 200, response.status
+    assert_params artist: 'david-bowie', song: 'changes'
+
+    get '/david-bowie/song-changes'
+    assert_equal 200, response.status
+    assert_params artist: 'david-bowie', song: 'changes'
+
+    get '/songs/song-changes'
+    assert_equal 200, response.status
+    assert_params song: 'changes'
+
+    get '/songs/changes-song'
+    assert_equal 200, response.status
+    assert_params song: 'changes'
+
+    get '/optional/songs/song-changes'
+    assert_equal 200, response.status
+    assert_params song: 'changes'
+
+    get '/optional/songs/changes-song'
+    assert_equal 200, response.status
+    assert_params song: 'changes'
+
+    get '/optional/david-bowie/changes-song'
+    assert_equal 200, response.status
+    assert_params artist: 'david-bowie', song: 'changes'
+
+    get '/optional/david-bowie/song-changes'
+    assert_equal 200, response.status
+    assert_params artist: 'david-bowie', song: 'changes'
+  end
+
+  private
+
+  def assert_params(params)
+    assert_equal(params, request.path_parameters)
+  end
+end