Skip to content

missing-return (ODW8110)

Preview (since 0.16.2.2) · Related issues · View source

Derived from the odoo linter.

Fix is sometimes available.

This rule is unstable and in preview. The --preview flag is required for use.

What it does

Checks that a method calling super() also has a return statement.

Why is this bad?

A method that calls super() but never returns its result (or any other value) usually means the return value of the base implementation is silently dropped.

Example

def write(self, vals):
    super().write(vals)

Use instead: 

def write(self, vals):
    return super().write(vals)

Fix safety

Every fix requires the method to call super() exactly once: with two calls, the value to hand back is a choice between them, and choosing is the author's job. Given that single call, there are two shapes where what to return is not a guess:

  • the call is the method's last statement, and the return goes in front of it. Nothing can be skipped by returning there, because nothing runs after it.
  • the call's result is assigned to a plain variable (res = super().default_get(fields)) at the top level of the method, and return res is appended at the end. Whatever the method does to res in between, res is the value it was building.

Anything else keeps the bare report: the call made inside an if or a loop, or its result assigned there, where the name may never be bound; the assignment target a tuple, an attribute or a subscript rather than a plain name; a method ending in raise, where the return would be dead code; and a call further down a chain, whose value is no longer the base implementation's.

The fix is marked unsafe because it changes what the method returns: callers that relied on the None of an implicit return now see the value the method was building. That is the point of the rule, but it is still a behavior change, and dropping the result is occasionally deliberate.

Options

Names the methods exempt from returning, not the ones checked.