Day 28:Assuming finally won’t execute after return

 

🐍 Python Mistakes Everyone Makes ❌

Day 28: Assuming finally Won’t Execute After return

This is a subtle Python behavior that surprises many developers.
Even after a return statement, Python still guarantees that the finally block runs.

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❌ The Mistake

def example():
    try:
      return "Success"
     finally:
       print("Cleanup code")

print(example())

Output:

Cleanup code 
Success

Many expect the function to return immediately—but Python disagrees.

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❌ Why This Fails?

• finally is designed for guaranteed execution

• Python executes finally before actually returning the value

• This applies even if:

  • return is used

  • An exception is raised

  • break or continue is used

The function only returns after finally finishes.

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✅ The Correct Understanding

Use finally when you must run cleanup code:

try:
    resource = open("file.txt")
    return resource.read()
finally:
   resource.close()

This ensures the file is closed—no matter how the function exits.

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✔ Key Takeaways

✔ finally always executes
✔ It runs even after return
✔ Cleanup code belongs in finally

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 Simple Rule to Remember

🐍 finally = “run this no matter what”