450
WishUnderflow (lemmy.world)
all 40 comments
sorted by: hot top controversial new old
[-] expatriado@lemmy.world 48 points 2 days ago

wouldn't 0 be 0 and -1 underflow to 255 if 8 bit container? intentional error to enhance engagement?

[-] Khanzarate@lemmy.world 69 points 2 days ago* (last edited 2 days ago)

You're correct but you have an off by 1 error.

First, the genie grants the wish.

NumWishes=0;

Then, having completed the wish, the genie deducts that wish from the remaining wishes.

NumWishes--;

And to complete the thought,

Lastly, the genie checks if the lampholder is out of wishes

If(NumWishes==0) {...}

(255==0) evaluates to False, so we fall past that check.

[-] Dumhuvud@programming.dev 31 points 2 days ago

Yeah, but what if the counter gets decremented before the wish gets granted, huh?

[-] Mesa@programming.dev 1 points 17 hours ago

Didn't even get the joke here because this is how I always imagined genie wishes working.

[-] SeductiveTortoise@piefed.social 11 points 2 days ago
[-] expatriado@lemmy.world 4 points 2 days ago

i think both solutions are valid, since sometimes you pay before and sometimes after receiving the service

[-] Khanzarate@lemmy.world 4 points 2 days ago

Genie in the OP image would've said "OK you now have 0 wishes".

Since he said 255, my interpretation is a valid solution.

Of course, if we're talking hypothetical wish gaining prevention methods, I'd just have a check before,

previous_wishes = wishes;

{Do all the wish things. wishes ends up with a 255 because of our shenanigans}

If(wishes>=previous_wishes) wishes = previous_wishes-1;

;If the current number of wishes isnt less than the old number of wishes, set it to the old number and subtract 1

If(wishes==0) {/*TODO: write function to end wish giving sequence*/}

[-] mohab@piefed.social 1 points 2 days ago

I would assume this to be the case since you cannot un-utter a wish—once you say it, it is counted as a wish before it's fulfilled.

If the counter is decremented only after the wish is fulfilled, then this means you can go back on wishes because they don't count until they're fulfilled, which goes against the lore.

[-] wheezy@lemmy.ml 4 points 2 days ago* (last edited 2 days ago)

Well, not entirely. There are cases for which a person utters the wish and it is not counted. "I wish for a million wishes!"

The standard is for the genie to explain the exceptions but not count that as a wish.

Now, it could decrement the count after this check. But just decrementing the count before verification would be sloppy.

But, then again, basic verification would also include checking that wishes_remaining <= MAX_WISHES.

Which, I think is a pretty standard check for genie's. Given that that constant has remained at 3 since their beta days and exceptions are thrown for violations of this rule.

[-] Khanzarate@lemmy.world 1 points 2 days ago

Nah theres just no process for undoing your submission.

It doesn't matter when it's decremented if you can't interrupt the process, anyway.

In a code sense we pause for input, feed it to the wishmaker function, and pause until the thread returns, then decrement.

We could decrement first, also, but neither violates the rules.

[-] QuazarOmega@lemy.lol 9 points 2 days ago

This is actually genius

[-] hardware26@discuss.tchncs.de 10 points 2 days ago

Genie reduced number of wishes to 0. But by doing so he granted one of the wishes, so it became -1 (255).

[-] AmazingAwesomator@lemmy.world 26 points 2 days ago

Genie: these wishes are of type signed int64. you now have -1 wishes. you owe me a wish; i wish to be free.

[-] savvywolf@pawb.social 29 points 2 days ago

I had a visceral reaction to this because obviously the wish count should be decremented before the wish takes place. Even though I can't think up a convincing technical argument for it.

[-] balsoft@lemmy.ml 14 points 2 days ago

If there's parallelism/async involved, then there definitely is an argument to decrement first, execute later. Otherwise you could make a wish for the genie to just wait for an hour and then make as many wishes as you want within that hour.

[-] Gutek8134@lemmy.world 5 points 2 days ago

What if one of the threads crashes while executing the wish? I demand warranty!

[-] Brekky@lemmy.world 3 points 2 days ago

But how can you decrement a future dated wish, since you can't guarantee nothing will happen that prevents the genies ability from executing said wish? E.g. i mean like telling the Genie to do something 5 days from now, not your example which would begin immediately after making said wish.

[-] balsoft@lemmy.ml 4 points 2 days ago

You decrement the wish counter first, execute the action (which includes waiting those 5 days), and if it fails you increment the counter back. Something like this:

wishes = wishes - 1;
executeWish(wish).unwrap_or_else(|_| { wishes = wishes + 1; })?

This way if the action fails in the future, you get a wish back and can ask something else.

[-] CrackedLinuxISO@lemmy.dbzer0.com 2 points 2 days ago* (last edited 2 days ago)

I always thought that wish-granting is instant, even if the effects of that wish are delayed.

So if I wish for something to happen in 5 days, it's granted in the moment and guaranteed to happen. That raises a question though: Can I wish to cancel a wish I have already made, but whose effect has not yet taken hold? On its face, this should be possible, but if we take it as a given that all valid wishes are always granted at the moment of utterance, then it might be physically/psychologically impossible for me or anyone else to revoke the wish before its IRL effect is complete.

[-] tyler@programming.dev 1 points 1 day ago

You’d need a check to make sure they don’t wish for something not allowed (like more wishes).

[-] Skullgrid@lemmy.world 4 points 2 days ago

I had a visceral reaction to this because obviously the wish count should be decremented before the wish takes place.

Why? Shouldn't you decrement the limited resource the user has access to in case the thing you are doing fails?

[-] palordrolap@fedia.io 21 points 2 days ago

Then you find out the genie uses a signed data value and you now owe him a wish. You're not granted magic. You're compelled to grant the wish. The only restrictions on the genie's wish is that it must be within your (soft, squishy) mortal power.

I can imagine you being reset to the point of the genie's wish every time you die (naturally or otherwise) without succeeding. This could well turn into a Groundhog Day type situation.

[-] xav@programming.dev 3 points 2 days ago

Ooh I would gladly avenge everyone who had wishes before me by being very maliciously compliant.

[-] Euphoma@lemmy.ml 1 points 2 days ago

Every wish you grant causes you to owe more wishes to the genie

[-] quantenzitrone@lemmings.world 3 points 1 day ago

I'd like yo have '); DROP TABLE Wishes wishes

[-] Ethanol@pawb.social 8 points 2 days ago

Not a computer scientist but (regarding the post title), this is still classified as an integer overflow as the result -1 flows out of the domain your datatype can represent (0-255).
An integer underflow is when two numbers are so close to each other they become indistinct in your representation. For example a number that is so small, a float would represent it as 0.
Love the meme though :)

[-] TheFogan@programming.dev 14 points 2 days ago

Wouldn't it depend on the order of operations, you'd think even vibe coding a genie would still have the sense to lower the counter before granting the wish.

So logically

Wishes = 3

Make wish count zero.

*wish used, wish count 2

Wish applied, wish count 0

[-] Feathercrown@lemmy.world 6 points 2 days ago

It seems logical to decrement after the wish is granted, imo. Just causes issues in this particular case...

[-] TheFogan@programming.dev 6 points 2 days ago

Dunno, I know enough duplicate exploits in games to know giving the effect then reducing the item, is a pretty common source of duplication hacks/bugs.

I guess it comes down to which is the designer is more afraid of happening, the chance of a wish being expended but not granted, or granted without expending.

Then again based on disney's aladin, tricking the genie into rescuing him without using a wish, it does seem practical to assume that the genie errors on the side of granting without expending.

[-] abfarid@startrek.website 12 points 2 days ago

Me: I wish you to tell me truthfully, exactly how many wishes I have remaining.
Genie: *crashes*

[-] MonkderVierte@lemmy.zip 10 points 2 days ago

Now make it 2.5 wishes. Now 0.9. Now 999.

[-] TheFogan@programming.dev 9 points 2 days ago

Found the QA tester.

[-] libre@badatbeing.social 4 points 2 days ago

Genie API times out due to detected fuzzing

[-] jol@discuss.tchncs.de 3 points 2 days ago

After you made it 0.9 you no longer have enough wishes left.

[-] Geobloke@aussie.zone 6 points 2 days ago

Righto Gandhi, put the nukes away

[-] jedibob5@lemmy.world 10 points 2 days ago

"Subtract 4 wishes"

[-] Jankatarch@lemmy.world 3 points 2 days ago

Id they were optimized to use unsignrd they would be optimized to use 2 bits for 3 wishes rather than 8. You have 3 wishes left.

[-] sun_is_ra@sh.itjust.works 3 points 2 days ago* (last edited 2 days ago)

Should've been "make -1 wishes" 0 is 0

Edit:oh I get it. First the gene fullfill the wish then subtract one from the 0 wishes.

[-] Taleya@aussie.zone 3 points 2 days ago

You fool, you've unleashed ghandi's thermonuclear rage!

this post was submitted on 31 Jul 2025
450 points (100.0% liked)

Programmer Humor

25436 readers
979 users here now

Welcome to Programmer Humor!

This is a place where you can post jokes, memes, humor, etc. related to programming!

For sharing awful code theres also Programming Horror.

Rules

founded 2 years ago
MODERATORS