Empty array instead of nil for source_extract

The source_extract method will return nil when it can't find the file name in
the backtrace, methods that consume this method expect an array and the nil ends
up causing type errors down the road like it happened here: #36341. This
patch refactors the source_extract method so that it returns an empty
array instead of nil when it can't find the source code.

Co-authored-by: Kasper Timm Hansen <kaspth@gmail.com>

1 files changed, 16 insertions, 0 deletions

diff --git a/actionview/test/template/template_error_test.rb b/actionview/test/template/template_error_test.rb
index c4dc88e4aa..643c29602b 100644
--- a/actionview/test/template/template_error_test.rb
+++ b/actionview/test/template/template_error_test.rb
@@ -34,4 +34,20 @@ class TemplateErrorTest < ActiveSupport::TestCase
 
     assert_equal "#<ActionView::Template::Error: original>", error.inspect
   end
+
+  def test_annotated_source_code_returns_empty_array_if_source_cant_be_found
+    template = Class.new do
+      def identifier
+        "something"
+      end
+    end.new
+
+    error = begin
+      raise
+    rescue
+      raise ActionView::Template::Error.new(template) rescue $!
+    end
+
+    assert_equal [], error.annotated_source_code
+  end
 end