Fiding memory leaks using tracemalloc

Hi Pythonistas!

In the last post we have learned about the advance profiling using tracemalloc. Today we are going to learn how to detect memory leak using tracemalloc. For the that we are using a function with mutable default argument. Let us dive into the code

import tracemalloc

tracemalloc.start(10)

def leak_memory(default_argument=[]):
    for _ in range(10**6):
        default_argument.append(1)

leak_memory()

snapshot = tracemalloc.take_snapshot()
top_stats = snapshot.statistics("lineno")

print("Possible memory leaks:")
for stat in top_stats[:5]:
    print(stat)

output

Possible memory leaks:
/home/afsal/Desktop/experiments/trace_malloc_post/memory_leak.py:7: size=8251 KiB, count=1, average=8251 KiB
/home/afsal/Desktop/experiments/trace_malloc_post/memory_leak.py:5: size=720 B, count=2, average=360 B

it show line 7 and 5 are the possible places they are

default_argument.append(1)
def leak_memory(default_argument=[]):

Which correct because the mutable default argument never reset each time this function is called 1000000 is append to that
default_argument when we call 10 times it become list of 10000000 1s in it.

Hope you have get an idea to find the memory leak using tracemalloc. Please share your valuable suggestions with 
afsal@parseltongue.co.in