feature detect for FNM_EXTGLOB for older Ruby. Fixes #15053

actionview/lib/action_view/template/resolver.rb

@@ -181,11 +181,7 @@ def find_templates(name, prefix, partial, details)
     def query(path, details, formats)
       query = build_query(path, details)
 
-      template_paths = Dir[query].reject { |filename|
-        File.directory?(filename) ||
-          # deals with case-insensitive file systems.
-          !File.fnmatch(query, filename, File::FNM_EXTGLOB)
-      }
+      template_paths = find_template_paths query
 
       template_paths.map { |template|
         handler, format, variant = extract_handler_and_format_and_variant(template, formats)
@@ -200,6 +196,26 @@ def query(path, details, formats)
       }
     end
 
+    if File.const_defined? :FNM_EXTGLOB
+      def find_template_paths(query)
+        Dir[query].reject { |filename|
+          File.directory?(filename) ||
+            # deals with case-insensitive file systems.
+            !File.fnmatch(query, filename, File::FNM_EXTGLOB)
+        }
+      end
+    else
+      def find_template_paths(query)
+        # deals with case-insensitive file systems.
+        sanitizer = Hash.new { |h,dir| h[dir] = Dir["#{dir}/*"] }
+
+        Dir[query].reject { |filename|
+          File.directory?(filename) ||
+            !sanitizer[File.dirname(filename)].include?(filename)
+        }
+      end
+    end
+
     # Helper for building query glob string based on resolver's pattern.
     def build_query(path, details)
       query = @pattern.dup