Remove flags that never change

How to do it

Keep every flag in one file, with an owner and an end date set when you add it. When the date passes, remove the flag, its setting and the losing branch in one change. Take the end date and owner from the register in Keep every flag in one register.

Examples

Python example

# Bad: on for everyone since last year
if flags.enabled("new_checkout"):
    new_checkout(cart)
else:
    old_checkout(cart)

# Good: the flag and the old branch are gone
new_checkout(cart)

TypeScript example

// Bad
if (flags.enabled('new_checkout')) newCheckout(cart);
else oldCheckout(cart);

// Good
newCheckout(cart);

How to check

A script lists flags past their end date and fails the build. In review, every flag has an owner and a date.

Sources

• CWE-570 Expression is Always False
• CWE-571 Expression is Always True
• CWE-561 Dead Code

Related rules

• ENG-25 Separate deploying from releasing in Engineering
• ENG-45 Keep every flag in one register in Engineering
• ENG-49 Reusing an old flag for new behaviour in Engineering
• ARC-59 Delete code that nothing uses in Clean code and architecture
• TST-57 Test both states of every live flag in Testing
• APP-49 Read feature flags before the first paint in Web app interface