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Sarj Code Standards

no-delete-statement

Avoid del statements; prefer constructing an immutable replacement value.

SARJ442 Rule source Tests Catalog JSON

Why

Deleting a name, attribute, or collection entry introduces lifetime or in-place mutation semantics that are harder to follow than explicit value construction.

Fix

Remove unused-value deletion markers. Rebuild collections with comprehensions, copies, or immutable value helpers such as dataclasses.replace. When an external API or deliberate lifetime boundary requires deletion, add an exact SARJ442 suppression on the statement and explain why.

Examples

Before — flagged Remove a redundant None deletion marker
app/request.py
def ready():
    def _ready():
        unused = None
        del unused
        return True


    return _ready()
After — preferred The retained assignment has no lifetime marker
app/request.py
def ready():
    def _ready():
        unused = None


        return True


    return _ready()
Autofix output
app/request.py
def ready():
    def _ready():
        unused = None


        return True


    return _ready()
Before — flagged Build a mapping without the removed entry
app/request.py
payload = dict(raw_payload)
del payload["secret"]
After — preferred Construct the desired mapping directly
app/request.py
payload = {key: value for key, value in raw_payload.items() if key != "secret"}

Formerly: no-deleted-only-override-parameter