static-key-dict-comprehension (B035)

Derived from the flake8-bugbear linter.

What it does

Checks for dictionary comprehensions that use a static key, like a string literal or a variable defined outside the comprehension.

Why is this bad?

Using a static key (like a string literal) in a dictionary comprehension is usually a mistake, as it will result in a dictionary with only one key, despite the comprehension iterating over multiple values.

Example

data = ["some", "Data"]
{"key": value.upper() for value in data}

Use instead:

data = ["some", "Data"]
{value: value.upper() for value in data}