Adding a Print Statement Made All Tests Pass -- Oppenheimer Reacts

Description

A meme using a still of Cillian Murphy as J. Robert Oppenheimer from the movie Oppenheimer (2023), wearing his iconic hat and looking contemplative/haunted in an outdoor setting. The top text reads 'REMEMBERING ALL THE "REMOVING A PRINT CAUSED A BUG" JOKES' and the bottom text reads 'WHEN ADDING A PRINT CAUSED ALL THE TESTS TO START PASSING'. The imgflip.com watermark is visible in the bottom right. The meme captures the existential dread of discovering that adding a simple print/log statement (which should have no side effects) somehow fixed failing tests -- a phenomenon related to timing-sensitive bugs, race conditions, or Heisenbugs where the act of observation changes the system behavior

Common Tags

Debugging Heisenbug RaceConditions ConcurrencyPatterns DebuggingTools UnitTesting DeveloperHumor SubtleBugs CodingHumor

Comments

Anonymous ★ Top Pick Now I am become println, the fixer of tests. The real Heisenbug is that you can't observe why the print fixes it without removing the print, which breaks it again

Anonymous ★ Top Pick

Now I am become println, the fixer of tests. The real Heisenbug is that you can't observe why the print fixes it without removing the print, which breaks it again
@artem_sidorin 7mo

Can someone share some jokes of the kind? Never heard one yet
@sysoevyarik 7mo

Those who witnessed the real power of UB will never smile in circus.
1. @drbogar 7mo
  
  What's an UB?
  
  @azizhakberdiev 7mo
  
  undefined behavior
  
  @drbogar 7mo
  
  Thanks!
  
  @sysoevyarik 7mo
  
  Happy man
  
  @rayslava 7mo
  
  Purpose of C++ existence 😒
@rayslava 7mo

Many race conditions can be resolved with print since writing to stdout is buffered and synchronous 🤷‍♂️
1. @azizhakberdiev 7mo
  
  do we call it a success if bug still exists but cannot be reproduced?
@pnlt_s 7mo

I made a Qt6 app, and it always caused a segfault on start if i removed void* __unused; from a header As you can guess, it was never used
@rafal35 7mo

I remember trying to fix a bug with my code in C but every time I would add a debug print, it would have a different bug instead, it nearly drove me insane lol
1. @sysoevyarik 7mo
  
  I once got a system crash (exclusively in a release build) due to assigning one large structure a value of { 0 }. I tried to find the cause of the crash with advanced technique called "binary code commenting", but this method didn't work, because the compiler discarded this assignment if the structure was not used further. I don't know how I guessed then that it was this assignment, but I fixed the bug by replacing the zeroing with memset.
@NaNmber 7mo

To be fair, recent units llm generated for me contain logger mocks and checks that it's called with exact text. I guess I have to remove them 🤔