[Solved] Identify the bug in the following Python code implementing deep copy for the Profile class: import copy class Profile: def __init__(self, name, scores): self.name = name self.... | OOP & Design Patterns

OOP & Design Patterns - Prototype Pattern - Deep Copy vs Shallow Copy

Identify the bug in the following Python code implementing deep copy for the Profile class:

import copy

class Profile:
    def __init__(self, name, scores):
        self.name = name
        self.scores = scores

    def __deepcopy__(self, memo):
        new_name = self.name  # Bug here
        new_scores = copy.deepcopy(self.scores, memo)
        return Profile(new_name, new_scores)

original = Profile('Alice', [10, 20])
copy_obj = copy.deepcopy(original)
copy_obj.scores.append(30)
print(original.scores)

ALine assigning new_name = self.name does not deepcopy the name string

BLine assigning new_scores = copy.deepcopy(self.scores, memo) incorrectly copies scores

CThe __init__ method does not initialize scores properly

DThe return statement returns a new Profile instead of modifying self

Step-by-Step Solution

Step 1: Examine __deepcopy__ method
The line new_name = self.name copies the reference to the name string instead of deep copying it.
Step 2: Understand impact
Strings are immutable in Python, so shallow copy is usually safe, but if name were a mutable object, this would cause shared references and bugs. Proper deep copy should be used for consistency.
Final Answer:
Option A -> Option A
Quick Check:
Only new_name assignment lacks deepcopy -> subtle bug [OK]

Quick Trick: All nested fields must be deep copied consistently [OK]

Common Mistakes:

MISTAKES

Forgetting to deepcopy all nested fields, assuming immutables are safe

Trap Explanation:

PITFALL

Candidates assume immutable fields don't need deepcopy, ignoring future mutability or consistency.

Interviewer Note:

CONTEXT

Checks attention to detail in overriding clone methods and understanding deep copy requirements.

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More OOP & Design Patterns Quizzes

Identify the bug in the following Python code implementing deep copy for the Profile class:

Step 1: Examine deepcopy method

Step 2: Understand impact

Final Answer:

Quick Check:

Want More Practice?

Identify the bug in the following Python code implementing deep copy for the Profile class:

Step 1: Examine __deepcopy__ method

Step 2: Understand impact

Final Answer:

Quick Check:

Want More Practice?

Step 1: Examine deepcopy method