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First argument to super() is not enclosing class

ID: py/super-not-enclosing-class
Kind: problem
Security severity: 
Severity: error
Precision: high
Tags:
   - reliability
   - maintainability
   - convention
   - external/cwe/cwe-687
Query suites:
   - python-security-and-quality.qls

Click to see the query in the CodeQL repository

The super class should be called with the enclosing class as its first argument and self as its second argument.

Passing a different class may work correctly, provided the class passed is a super class of the enclosing class and the enclosing class does not define an __init__ method. However, this may result in incorrect object initialization if the enclosing class is later subclassed using multiple inheritance.

Recommendation

Ensure that the first argument to super() is the enclosing class.

Example

In this example the call to super(Vehicle, self) in Car.__init__ is incorrect as it passes Vehicle rather than Car as the first argument to super. As a result, super(SportsCar, self).__init__() in the SportsCar.__init__ method will not call all __init__() methods because the call to super(Vehicle, self).__init__() skips StatusSymbol.__init__().



class Vehicle(object):
    pass
        
class Car(Vehicle):
    
    def __init__(self):
        #This is OK provided that Car is not subclassed.
        super(Vehicle, self).__init__()
        self.car_init()
        
class StatusSymbol(object):
    
    def __init__(self):
        super(StatusSymbol, self).__init__()
        self.show_off()
        
class SportsCar(Car, StatusSymbol):
    
    def __init__(self):
        #This will not call StatusSymbol.__init__()
        super(SportsCar, self).__init__()
        self.sports_car_init()

        
#Fix Car by passing Car to super().
#SportsCar does not need to be changed.
class Car(Car, Vehicle):
    
    def __init__(self):
        super(Car, self).__init__()
        self.car_init()

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