CodeQL documentation

Unnecessary delete statement in function

ID: py/unnecessary-delete
Kind: problem
Severity: warning
Precision: high
Tags:
   - maintainability
   - useless-code
Query suites:
   - python-security-and-quality.qls

Click to see the query in the CodeQL repository

Passing a local variable to a del statement results in that variable being removed from the local namespace. When exiting a function all local variables are deleted, so it is unnecessary to explicitly delete variables in such cases.

Recommendation

Remove the del statement.

Example

In the function below, the variable x is assigned a value that is used for a calculation, and is then explicitly deleted before the function exits. In this case, the delete statement can be removed without changing the behavior of the function.

def unnecessary_delete():
    x = get_some_object()
    do_calculation(x)
    del x                       # This del statement is unnecessary

References