Fix #29632 - nil #path leads to NoMethodError in LoadError#is_missing?

See #29632 for details. In short, it's possible to enter `LoadError#is_missing?` when `LoadError#path` returns `nil`, leading to `path.sub` throwing an none-to-helpful `NoMethodError`.

This tiniest of patch inserts `#to_s` before the `sub` call to make sure it succeeds. Affected surface area should be just as tiny since something has already gone wrong to get us into `#is_missing?` and the current behavior when `#path` returns `nil` seems clearly not intended.

[Gannon McGibbon + Neil Souza]

2 files changed, 8 insertions, 1 deletions

diff --git a/activesupport/lib/active_support/core_ext/load_error.rb b/activesupport/lib/active_support/core_ext/load_error.rb
index 750f858fcc..6b0dcab905 100644
--- a/activesupport/lib/active_support/core_ext/load_error.rb
+++ b/activesupport/lib/active_support/core_ext/load_error.rb
@@ -4,6 +4,6 @@ class LoadError
   # Returns true if the given path name (except perhaps for the ".rb"
   # extension) is the missing file which caused the exception to be raised.
   def is_missing?(location)
-    location.sub(/\.rb$/, "".freeze) == path.sub(/\.rb$/, "".freeze)
+    location.sub(/\.rb$/, "".freeze) == path.to_s.sub(/\.rb$/, "".freeze)
   end
 end
diff --git a/activesupport/test/core_ext/load_error_test.rb b/activesupport/test/core_ext/load_error_test.rb
index 41b11d0c33..126aa51cb4 100644
--- a/activesupport/test/core_ext/load_error_test.rb
+++ b/activesupport/test/core_ext/load_error_test.rb
@@ -7,13 +7,20 @@ class TestLoadError < ActiveSupport::TestCase
   def test_with_require
     assert_raise(LoadError) { require "no_this_file_don't_exist" }
   end
+
   def test_with_load
     assert_raise(LoadError) { load "nor_does_this_one" }
   end
+
   def test_path
     begin load "nor/this/one.rb"
     rescue LoadError => e
       assert_equal "nor/this/one.rb", e.path
     end
   end
+
+  def test_is_missing_with_nil_path
+    error = LoadError.new(nil)
+    assert_nothing_raised { error.is_missing?("anything") }
+  end
 end