Sanity Check: Has this ever happened to you?

ppowell

You are trying to debug a script that is locking up resources, when all of a sudden you decide to put a well-placed die('blah blah'); line in your code and POOF, everything works! Note that the script never "dies", it completes processing while seemingly ignoring the die('') line, but when you remove the die('') line it continues to work.

Has this ever happened with you? Happened with me for years in PHP 4 and 5.

Phil

Bunkermaster

In the many lines of code and many scripts I coded, I have never encountered this behavior 😕

dougal85

Up all night programming? I know these things happen to me at about 4 in the morning - IE. I have a problem (probably a stupid one i cant see for being too tired) and then i somehow fix it and not sure how i did fix it.

I think that's what ppowell means, rather than a specific problem with die().

etully

That's never happened to me. Is it reproduceable? Can you make it happen with a simple 2 line script? If you re-type the script onto a different machine, does the problem happen there too?

It almost sounds like (a) a quirky install of PHP, (😎 a hidden control character in your code, or (c) a side effect caused by low level PHP processsing - for example, the mere presence of the "die" command (even if unused) might be causing PHP to perform some action that wouldn't happen if the die command weren't there.

Have I seen unexplained weirdness with computers? Sure. The key is whether or not they are reproduceable on other systems and consistently happening with the same code.

Sxooter

I have had something similar happen, where I added an echo statement to the middle of my code as a poor man's debugger.

Suddenly, the delay introduced by the echo statement made the script start working.

It was php-oracle, and I needed a short delay after telling oracle to parse the query before I told it to execute it. So, I replaced the echo with a usleep(10) and it worked fine.

NogDog

Sxooter wrote:
I have had something similar happen, where I added an echo statement to the middle of my code as a poor man's debugger.

Suddenly, the delay introduced by the echo statement made the script start working.

It was php-oracle, and I needed a short delay after telling oracle to parse the query before I told it to execute it. So, I replaced the echo with a usleep(10) and it worked fine.

Sounds like a multi-threaded ADA program I was testing many years ago. I ran into a bug, but whenever the developer attached the debugger process so she could view variables, the stack, etc. when the expected crash occurred, everything would work fine. Eventually, after a couple hours of manual code review, she found a place where there could be a race condition with another process. Sure enough, when she added a few lines of code to deal with that, things ran fine with or without the debugger attached. Apparently, the overhead of having the debugger process running was just enough to prevent that fatal race condition from occurring.

bpat1434

In a similar situation....

The company I work for develops on Macs mainly. I develop on Windows. The servers are Linux. When other developers make files or modifications and save them, they upload from Mac to Linux. I upload Windows to Linux. My editor (Edit Plus) automatically saves files in Unix format (by my preference). So one day things "stop working" for a specific feature. I download the file, compare and they're technically the same, except for line-endings. I change the line-endings form \r\n to \n and re-upload. Poof!! The errors are gone, and the feature works.

The only reason I caught it is because my personal server said there was no function defined and output the php script on one line. Had I not tried it on my server, I'm sure I'd still be scratching my head, because it never would have crossed my mind to check line-endings...

And yes, I've seen the same kind of issue where adding an echo or die or print statement makes it work. Happened to me a couple times. Never really know what causes it to work, but after I remove it, it works fine from then on....