Invert conditional to avoid double checking for Regexp

activemodel/lib/active_model/validations/format.rb

@@ -32,23 +32,24 @@ def record_error(record, attribute, name, value)
         record.errors.add(attribute, :invalid, options.except(name).merge!(value: value))
       end
 
-      def regexp_using_multiline_anchors?(regexp)
-        source = regexp.source
-        source.start_with?("^") || (source.end_with?("$") && !source.end_with?("\\$"))
-      end
-
       def check_options_validity(name)
         if option = options[name]
-          if !option.is_a?(Regexp) && !option.respond_to?(:call)
+          if option.is_a?(Regexp)
+            if options[:multiline] != true && regexp_using_multiline_anchors?(option)
+              raise ArgumentError, "The provided regular expression is using multiline anchors (^ or $), " \
+              "which may present a security risk. Did you mean to use \\A and \\z, or forgot to add the " \
+              ":multiline => true option?"
+            end
+          elsif !option.respond_to?(:call)
             raise ArgumentError, "A regular expression or a proc or lambda must be supplied as :#{name}"
-          elsif option.is_a?(Regexp) &&
-                regexp_using_multiline_anchors?(option) && options[:multiline] != true
-            raise ArgumentError, "The provided regular expression is using multiline anchors (^ or $), " \
-            "which may present a security risk. Did you mean to use \\A and \\z, or forgot to add the " \
-            ":multiline => true option?"
           end
         end
       end
+
+      def regexp_using_multiline_anchors?(regexp)
+        source = regexp.source
+        source.start_with?("^") || (source.end_with?("$") && !source.end_with?("\\$"))
+      end
     end
 
     module HelperMethods