raise-within-try (TRY301)

Derived from the tryceratops linter.

What it does

Checks for raise statements within try blocks. The only raises caught are those that throw exceptions caught by the try statement itself.

Why is this bad?

Raising and catching exceptions within the same try block is redundant, as the code can be refactored to avoid the try block entirely.

Alternatively, the raise can be moved within an inner function, making the exception reusable across multiple call sites.

Example

def bar():
    pass


def foo():
    try:
        a = bar()
        if not a:
            raise ValueError
    except ValueError:
        raise

Use instead:

def bar():
    raise ValueError


def foo():
    try:
        a = bar()  # refactored `bar` to raise `ValueError`
    except ValueError:
        raise