When we add new, optional features, we often put in a flag to enable or disable the feature for certain users. This allows us to slowly roll-out the feature, or only enable it for customers that pay the premium. If there’s problems, you can also disable the feature quickly without pushing out a new version of our software.
One team had decided to rename their module, and therefore were updating the configuration flag’s name.
A lead developer, who reviewed the change, questioned if they could do that without running into incompatibility issues. The project team’s lead stated:
“No, we have the feature validation at source and target separately before we do anything. So, there should not be any compatibility issues.”
Project Lead
However, I was convinced the lead developer was correct. We have multiple versions of our software deployed, but we only have one version of the Configuration Manager tool.
So let’s say in Version1, the new module is called “User Manager“, but in Version2 they want the module to now be called “Staff Management” – and so they update the main software and the Configuration Manager tool to use this new name.
When we use the Configuration Management tool for new users that are using Version1, we update their config to use the new name “Staff Management“, however Version1‘s software will be looking for “User Manager” and will not find it, so will think the module is disabled.
Existing users on Version1 with the old flag in their configuration will work as normal, but it won’t work for new users. For Version2 users, the Configuration will have to be redeployed since their config will have the old name, but Version2 will be looking for the new name.
If the Configuration Management tool used ID’s rather than matching on text; it wouldn’t be a problem, so we have screwed ourselves over there. Matching on text is rarely a good idea due to possible spelling mistakes, case sensitivity (is “User Manager” the same as “user manager“?), and usually less efficient matching on something else like a number ID.
I spent a while trying to think of ways around this issue. Ideas that I thought of involved writing complex database scripts, running scripts outside the release process and getting other people involved. But then I think all my ideas still wouldn’t solve the incompatibility issues and it seemed way too much work for something trivial.
The team were adamant they wanted to rename it though, but it didn’t really matter too much. Only our staff see the Configuration Management tool, and we can update the main software so the users see the new name. It just adds confusion if someone tells you to enable “Staff Management” but you can’t see the option, so they have to correct themselves and ask for “User Manager” instead.
I would have thought the project team would have ran through different scenarios to test if their idea was feasible for new and existing users. But even after questioning it was feasible, they were adamant there wouldn’t be any compatibility issues so I had to explain the scenarios to them.
Related Blogs:
Stranger Coding Tings 