FIX: 'reply by email addresses' site settings should allow email addresses without a 'reply_key' when 'find related post with key' is disabled

config/site_settings.yml

@@ -705,6 +705,7 @@ email:
     validator: "ReplyByEmailEnabledValidator"
   reply_by_email_address:
     default: ''
+    validator: "ReplyByEmailAddressValidator"
   alternative_reply_by_email_addresses:
     default: ''
     validator: "AlternativeReplyByEmailAddressesValidator"

lib/validators/reply_by_email_address_validator.rb

@@ -4,11 +4,14 @@ class ReplyByEmailAddressValidator
   end
 
   def valid_value?(val)
-    return true if val.blank?
+    return true  if val.blank?
+    return false if val["@"].nil?
 
-    !!val["@"] &&
-    !!val["%{reply_key}"] &&
-    val.gsub(/\+?%{reply_key}/, "") != SiteSetting.notification_email
+    if SiteSetting.find_related_post_with_key
+      !!val["%{reply_key}"] && val.sub(/\+?%{reply_key}/, "") != SiteSetting.notification_email
+    else
+      val != SiteSetting.notification_email
+    end
   end
 
   def error_message

spec/components/validators/reply_by_email_address_validator_spec.rb

@@ -18,6 +18,11 @@ describe ReplyByEmailAddressValidator do
       expect(validator.valid_value?('foo@bar.com')).to eq(false)
     end
 
+    it "returns true if value does not contain '%{reply_key}' but 'find_related_post_with_key' is also disabled" do
+      SiteSetting.expects(:find_related_post_with_key).returns(false)
+      expect(validator.valid_value?('foo@bar.com')).to eq(true)
+    end
+
     it "returns false if value is the same as SiteSetting.notification_email" do
       SiteSetting.expects(:notification_email).returns("foo@bar.com")
       expect(validator.valid_value?('foo+%{reply_key}@bar.com')).to eq(false)