fixit-blank-lines

Reusable Fixit rules for blank-line and statement-cuddling policy checks.

Installation

pip install "git+https://github.com/zigai/flake8-blank-lines.git"

uv add "git+https://github.com/zigai/flake8-blank-lines.git"

Quick Start

Add the rule pack to your project configuration:

[tool.fixit]
root = true
enable = ["fixit_blank_lines.rules"]
disable = [
  "fixit_blank_lines.rules:BlockHeaderCuddleStrict",
]

Run linting and autofix:

fixit lint <path>
fixit lint --diff <path>
fixit fix --automatic <path>

For in-file suppressions, use Fixit comments:

• # lint-ignore: RuleName
• # lint-fixme: RuleName

Rules

NoSuiteLeadingTrailingBlankLines (BL100, BL101)

Removes leading and trailing blank lines at suite boundaries.

Before:

def f() -> int:

    value = 1
    return value

After:

def f() -> int:
    value = 1
    return value

BlankLineBeforeBranchInLargeSuite (BL200)

In suites larger than 2 non-empty lines, requires a blank line before return/raise/break/continue.

Before:

def f(value: int) -> int:
    x = value + 1
    y = x + 1
    z = y + 1
    return z

After:

def f(value: int) -> int:
    x = value + 1
    y = x + 1
    z = y + 1

    return z

BlockHeaderCuddleRelaxed (BL300)

Allows assignment-before-block cuddling only when the final prep assignment feeds the block header or first body statement. The first statement after a suite docstring is exempt (Ruff D202 compatibility).

Before:

def f(value: int) -> int:
    prepared = value + 1
    if value > 0:
        return value

    return 0

After:

def f(value: int) -> int:
    prepared = value + 1

    if value > 0:
        return value

    return 0

BlockHeaderCuddleStrict (BL301)

Stricter cuddle mode: only the immediately previous assignment may feed the block header. The first statement after a suite docstring is exempt (Ruff D202 compatibility).

Before:

def f(value: int) -> int:
    header_value = value + 1
    trailing = value + 2
    if header_value > 0:
        return header_value

    return 0

After:

def f(value: int) -> int:
    header_value = value + 1
    trailing = value + 2

    if header_value > 0:
        return header_value

    return 0

BlankLineAfterControlBlock (BL350)

Requires a separator after multiline control-flow blocks.

Before:

def f(value: int) -> int:
    if value > 0:
        value += 1
    return value

After:

def f(value: int) -> int:
    if value > 0:
        value += 1

    return value

BlankLineBeforeAssignment (BL210, disabled by default)

Requires a separator before an assignment when it follows a non-assignment statement, except when the assignment directly follows a suite docstring.

Before:

def f() -> int:
    log_start()
    value = compute()
    return value

After:

def f() -> int:
    log_start()

    value = compute()
    return value

MatchCaseSeparation (BL400, disabled by default)

Requires a separator before the next case when a case body is larger than 2 non-empty lines.

Before:

def f(value: int) -> int:
    match value:
        case 1:
            a = 1
            b = 2
            c = 3
        case _:
            return 0

After:

def f(value: int) -> int:
    match value:
        case 1:
            a = 1
            b = 2
            c = 3

        case _:
            return 0

License

MIT