I would like to create a Rector rule to remove feature flags (after they are no longer needed)

[paulshryock]

Sometimes I write new features behind a feature flag. Let's say the code looks something like:

if (isFeatureFlagActive('my-feature'))
  doMyFeature();

But later, often times this code is left much longer than it needs to, and it doesn't always get removed in a timely manner, and the amount of feature flags that we have builds up.

User story

• AS A software engineer,
• I WANT TO run Rector with a rule to remove the 'my-feature' feature flag,
  • AND when that runs, the code (above) looks like the code (below),
• SO THAT the process of removing feature flags is quick and easy.

End result after running Rector

doMyFeature();

Is this possible with Rector out-of-the-box? Would I need to write a custom Rector rule? What's the best approach?

[mspirkov]

It seems to me that "out of the box" this is not supported, because it looks like a custom feature.
In my opinion, a good solution would be to write a custom rule. It shouldn't be difficult, but you will be able to configure it as you wish.

[TomasVotruba]

We do not have such a rule yet. Using feature flags can be quite custom, from fuctions, through constants, method calls, static calls. Then same but with arguments. Making such rule generic could be a mess to describe in docs.

Writing such a custom rule for your use case it matter of hooking rule to FuncCall with name + arg, then if found, return if->stmts. 10-15 lines. That's why better go with a custom rule.

[paulshryock]

Thank you both! This is the guidance I was hoping for. Much appreciated.