Memory Leak Debugger

Memory Leak Debugger

Prerequisites & Dependencies

• Node.js with --inspect / Chrome DevTools, or Python tracemalloc, or Go go tool pprof
• Access to heap snapshots or memory profiling tools
• Basic understanding of GC roots and reference cycles

Execution Steps

1. Start the application with memory profiling enabled (node --inspect, python -m tracemalloc, go pprof http://localhost:6060)
2. Exercise the app until the leak becomes noticeable (growing heap size, OOM warnings)
3. Take a heap snapshot and compare it over time (heap-diff, tracemalloc.compare_to, pprof web)
4. Identify retaining objects: look for large arrays, closures, DOM/event listeners, or unresolved Promises
5. Remove unexpected references: clear timers/intervals, remove event listeners (removeEventListener), use WeakMap/weakref where appropriate
6. Re-run the profile to confirm the leak is sealed, and add automated memory regression tests

# Python example: detecting leaks with tracemalloc
import tracemalloc

tracemalloc.start()

def allocate_leak():
    # simulate unbounded growth
    data = [] * 10000  # grows each call
    return data

# Run and snapshot
snapshot = tracemalloc.take_snapshot()
top_stats = snapshot.compare_to(tracemalloc.take_snapshot(), 'lineno')
for stat in top_stats[:5]:
    print(stat)