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Search - "spot the error"
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A student sent me his code to look for the cause of an error. I spent 2 hours researching if there are any breaking changes in the latest version of AngularJS. Everything looked fine. I could not spot any errors. I tried copying and pasting my own script and link tags, and it worked. I put back his tags, and again got an error.
I almost shot myself in the head when I saw type="text/javascritp" in the script tag he used. I didn't know how to react. It could happen to anybody but I wanted to punch him. Feeling better now.5 -
Let's play spot the error!
Hint:
THERE'S A COMMA ON THE END OF THE LINE THAT HAS BEEN CAUSING MY LIST TO BE WRAPPED IN A SECOND LIST AND IT HAS TAKEN ME AN HOUR TO FIND.
Good luck finding it, it's hard!2 -
The world is full of write-only devs. People who never look at the code they create or change.
That's the only explanantion I can find for the fact that everytime I look into some code I have never touched or haven't seen for a while, I instantly spot at least one error that is so elementary, that there is absolutely no chance to miss it.2 -
Ok now I'm gonna tell you about my "Databases 2" exam. This is gonna be long.
I'd like to know if DB designers actually have this workflow. I'm gonna "challenge" the reader, but I'm not playing smartass. The mistakes I point out here are MY mistakes.
So, in my uni there's this course, "Databases 2" ("Databases 1" is relational algebra and theoretical stuff), which consist in one exercise: design a SQL database.
We get the description of a system. Almost a two pages pdf. Of course it could be anything. Here I'm going to pretend the project is a YouTube clone (it's one of the practice exercises).
We start designing a ER diagram that describes the system. It must be fucking accurate: e.g. if we describe a "view" as a relationship between the entities User and Video, it MUST have at least another attribute, e.g. the datetime, even if the description doesn't say it. The official reason?
"The ER relationship describes a set of couples. You can not have two elements equal, thus if you don't put any attribute, it means that any user could watch a video only once. So you must put at least something else."
Do you get my point? In this phase we're not even talking about a "database", this is an analysis phase.
Then we describe the type dictionary. So far so good, we just have to specify the type of any attribute.
And now... Constraints.
Oh my god the constraints. We have to describe every fucking constraint of our system. In FIRST ORDER LOGIC. Every entity is a set, and Entity(e) means that an element e belongs to the set Entity. "A user must leave a feedback after he saw a video" becomes like
For all u,v,dv,df,f ( User(u) and Video(v) and View(u, v, dv) and feedback(u, v, f) ) ---> dv < df
provided that dv and df are the datetimes of the view and the feedback creation (it is clear in the exercise, here seems kinda cryptic)
Of course only some of the constraints are explicitly described. This one, for example, was not in the text. If you fail to mention any "hidden" constraint, you lose a lot of points. Same thing if you not describe it correctly.
Now it's time for use cases.
You start with the usual stickman diagram. So far so good.
Then you have to describe their main functions.
In first order logic. Yes.
So, if you got the point, you may think that the following is correct to get "the average amount of feedback values on a single video" (1 to 5, like the old YT).
(let's say that feedback is a relationship with attribute between User and Video
getAv(Video v): int
Let be F = { va | feedback(v, u, va) } for any User u
Let av = (sum forall f in F) / | F |
return av
But nope, there's an error here. Can you spot it (I didn't)?
F is a set. Sets do not have duplicates! So, the F set will lose some feedback values! I can not define that as a simple set!
It has to be a set of couples, like (v, u), where v is the value and u the user; this way we can have duplicate feedback values in our set.
This concludes the analysis phase. Now, the design.
Well we just refactor everything we have done until now. Is-a relations become relationships, many-to-many relationships get an "association entity" between them, nothing new.
We write down on paper every SQL statement to build any table, entity or not. We write down every possible primary key or foreign key. The constraint that are not natively satisfied by SQL and/or foreign keys become triggers, and so on.
This exam is considered the true nightmare at our department. I just love it.
Now my question is, do actually DB designers follow this workflow? Or is this just a bloody hard training in Pai Mei style?6 -
If they followed my suggestion and went straight to debugging the server issues they would have been solved it from week 1 and everyone would have thought the migration had a minor performance hiccup. In fact, we have already done such at least twice before and nobody batted an eye.
Instead they self-labelled the migration a failure on first error, setting the stage for apologizing to the client, and put themselves on the spot for a whole staging / production signoff, replication / backup worfklow, almost a blue-green "seamless" deployment reminiscent of DigitalOcean.
Well they're not DigitalOcean, and anyone who has spent any time understanding users knows they will not participate in "new system" tests long enough to find or report issues.
So of course the migration stretched out to almost three months up until the whole reason for the migration - the rapidly escalating risk of the old provider disappearing - hit like a freight train and now they have to go through the problem of debugging the server like I told them to on week 1. Only this time they've set the client mindset against it, lost any chance of reverting, have had grave risk for data loss, and are under pressure to debug other people's code in real-time.
This is why I don't trust devs to do ops. A dev's first solution to any problem is to throw tech at it. -
I decided to tweak my two years old-mild overclocking on my main/home pc, to get more juice out of it.
Started with small steps running benchmarks each time I upped the clock.
Didnt crash me once up until it crashed while windows was booting after restart.
I thought to myself, that's normal, now I just have to lower it a bit until I find the sweet spot.
After windows finished crash dumping, restarted, lowered clock from bios, and headed to boot windows.
Windows recovery came up to scan my installation, pretty normal after a bsod.
I was waiting for it to finish, thinking that ofc there is no error you silly windows, until the recovery said that it could not recognize the error.
Proceeding to boot normal windows via the correspndent button in the recovery, the recovery itself came up again scanning for errors. I waited again only for the same outcome, and restarted my pc.
Yeap the recovery again scanning for errors.
How the hell did my boot became corrupted after just a crash. I've been fighting since yesterday for hours to fix this shitty situation but to no avail. I really dont want to clean install...
I couldnt even sleep well last night thinking that I have to fix this after work today...
Fuck my life, fuck windows3 -
The feeling when you didn't spot what the error was here:
int x = 0;
int y = 0;
for ( ; y < rows; y++) {
for ( ; x < cols; x++) {
//Dafuq, only does one line?!
}
}10 -
Below is a transcript from work Slack today. Only the names and some code are changed. It ended up causing a bit of drama. DevRanters, what do you take from this?
---
Delivery Lead:
Hey Gang. What's the blocker for FEATURE-123?
Dev1:
FEATURE-122 crashed on iOS app when viewing Feature Introduction page.
Teach Lead:
I've talked about this with Dev1 on a side channel.
And diagnosed the stack trace.
It looks like there is/was some bad handling of a List in the Feature Introduction view logic.
But this is confined to changes that Dev2 is still working on.
(It's not present in master)
Dev2, what's your current position on this?
Dev2:
I have tested at my end with Dev1 but it seems to be working fine
Tech Lead:
There is a race condition related to the use of someList.first()
My guess is that theres a Flow of those lists defined, with an initial value of emptyList
And that on your machine, that Flow is updating with a new value quickly enough that it doesn't matter.
But on Dev1's, for whatever reason, it doesn't get there in time, hits the empty list and falls over.
The logic that's performing the first() needs to gracefully handle empty lists as well.
Dev2:
Where is that logic called?
Tech Lead:
Here's the stack trace Dev1 provided in our conversation earlier:
Caused by: kotlin.NoSuchElementException: List is empty.
...
at 3 iosApp 0x00000000 kfun:kotlin.NoSuchElementException#<init>(kotlin.String?){} + 00
at 4 iosApp 0x0000000 kfun:kotlin.collections#first@kotlin.collections.List<0:0>(){0§<kotlin.Any?>}0:0 + 000
...
at 9 iosApp 0x0000000 kfun:kotlin.coroutines.native.internal.BaseContinuationImpl#resumeWith(kotlin.Result<kotlin.Any?>){} + 0000
This line:
kfun:kotlin.collections#first@kotlin.collections.List<0:0>()
...says that it's first() being called on an empty list.
Dev1:
FYI: Dev3/Dev4/myself are seeing the same issue with the same stack-trace above.
Tech Lead:
So Dev2, have you introduced such a call?
Because I checked master branch and there isn't one, in that version of the file.
Ok, I'll check your working branch Dev2
...
Yes you have here:
var processed1 = someList.first()
var processed2 = someList.first()
...
Lines 123, 124.
Solution looks really straightforward guys.
Dev2:
Okay, I will fix that and push the change
Tech Lead:
Check if someList is empty and allow for generating / handling null processedValues in the view.
Now; I'm going to be straight with you here.
This issue has been discussed over several hours today.
I expect that either one of you could have gone through the process I did in the last 10 minutes above, and resolved it in the same way :point_up:
Dev2:
I went on a break and it's not reproducible on my machine
Tech Lead:
I didn't reproduce it on mine either.
Dev1:
Dev2 and myself are now on sharing screen to sort this issue out. Hope to update back later.
Tech Lead:
<Screen shot of diff with changed code>
:point_up: That change should do it.
Dev2:
Already have pushed the change.
Tech Lead:
...just seen it, is good - same approach :ok_hand:
Dev1 please let us know when tested on your machine.
Dev1:
That does it. It fixes the issues. Thank you, Dev2. I will pick it off from here.
Tech Lead:
Glad to hear it guys.
Dev1:
I have to say this that it is not because we are not working on the issue - Dev2 and myself (together with Dev3/Dev4) have been on this issue all this morning. It just difficult to connect the dot when it wasn't reproducable on Dev2's machine. I brought the issue up because I wanted to switch to working on other tickets while waiting for this to resolve. Still thank you largely for Dev2's work and your keen eyes that spot and resolve the issue quickly.
Tech Lead:
Noted Dev1.
I think the take-away has to be to read the stack-trace carefully... don't worry - we've all been guilty of not reading the error in full, at some point.
The stack trace said that the 'first' element is being referenced from an empty list - that's just logically impossible, right?
Looking for that call to first, we saw it wasn't in the code before, and is after (two of them, in fact).
So then we ask ourselves, how can we deal with an empty list - and then solution almost presents itself.
It didn't really take reproduction of the error to resolve.
Maybe working with a new tech stack creates an anxiety that every issue faced will have a complex solution related to that stack; but I think you'll agree, this particular issue really just required a deep breath and your trusty 'debugging skills 101'... don't lose them! :smiling_face:4 -
I've refrained from commenting on which IDE is best and which isn't, what simply works for me is eclipse. So far it handles stuff for me pretty nicely... until today.
Look at this screenshot, can you spot the wtf? Like, SRSLY, WTF.... Might it really be just that DOT at the end or is it just the dot concatenated at the end of the error message?13 -
The ridiculous and shameful story of how simply "installing Windows" saved my hard drive from the garbage.
(Also update on https://devrant.com/rants/3105365/)
It started with my root partition turning read-only all of a sudden. Some quick search suggested that I should check the sanity of my hard drive, by running a SMART test, which failed of course. I backed up my data using ddrescue and ran a badblocks over the whole thing, which found around 800 unreadable blocks in a row. I was ready to bid farewell to my drive, but as a last resort, instead of the trash, I brought it to this place where they claimed they can repair the damaged hard drives by "surgery".
To my surprise, they returned my drive the next week, saying it is all well now, and charged me 1/8 the price of a new drive, with a refund guarantee if there was a problem in two days. There was a problem right there: I ran another SMART test which failed again, and also the faulty blocks were still unreadable! So I stormed the place and called for my refund, showing the failed SMART report. The only answer I would get from the staff was "Have you tried installing Windows?".
I usually try to be patient in such situations; I really don't like to declare publicly that "not everyone uses that stinky piece of rotten software you call an OS", but their suggestion seemed totally irrelevant! I got all types of IO errors all over the damn thing and they told me to install Windows. Why? Because this was the only test they would rely on. At last I managed to meet the "technician" there and showed him the IO errors: tried to read the bad sectors with dd and failed. He first mumbled somethings like "Have you checked the connector?" or "Are these the same blocks?", but after he ran out of bullshit, he said "Why don't you just install Windows first and see if that helps?" and I was ready to explode in his face!
"You test drives by installing Windows, just because it will make a nasty NTFS partition and probably does an fsck? If you shut your mouth for a sec and open your eyes you'll see this is a shit load of IO errors we got here: You can't install Windows, you can't even make an NTFS here, because it will try to zero-the-fuck-out the damn partition and it will face the same fucking IO error that I'm showing you right now in almost one single fucking system call!"
"I don't know this kind of test you are using. We have our own tests and they've passed successfully. So all I can do is to give you a Windows CD if you want."
"I don't need a Windows CD. I will just try to make an NTFS partition on the error spot and I will fail."
"Ok. Then call me when your done."
I was angry, not only because I felt they're just trying to avoid a refund, but also because I knew I've lost my drive. But just with hope that I could get my money back, I made a small partition over the error spot and ran `mkfs.ntfs` on it. I was ready to show the failure to the guy, but I looked more precisely and saw that "the filesystem was created successfully!" I was sure something is nor write. I then successfully mounted the new partition, write over it and read it again. I even dd'ed the blocks again, and this time there was no IO error. All of a sudden everything was fine.
I didn't know what happened. Maybe it just needed a write, while I'd just tried to read from those blocks. But anyway, I didn't called the technician guy again. I just thanked one of the staff there and said that my problem was solved. I then ran a successful SMART test and then restored my backup. Ridiculous like that.
I'm still not sure if my drive will continue to live with no more problems. I also have no explanation for what happened. (I appreciate any help on this https://superuser.com/questions/...) But I really like to see the look on the poor guy's face when he finds out that trying to install Windows just saved my ass!11 -
Any Windows Sysadmins here? I have a question for you - How do you do it?
I only very rarely have to do something that would fall under "Windows System Administration", but when I do... I usually find something either completely baffling, or something that makes me want to tear our my hair.
This time, I had a simple issue - Sis brought me her tablet laptop (You know, the kind of tablets that come with a bluetooth keyboard and so can "technically" be called a laptop) and an SD card stating that it doesn't work.
Plugging it in, it did work, only issue was that the card contained file from a different machine, and so all the ACLs were wrong.
I... Dealt with Windows ACLs before, so I went right to the usual combination of takeown and icacls to give the new system's user rights to work with the files already present. Takeown worked fine... But icacls? It got stuck on the first error it encountered and didn't go any further - very annoying.
The issue was a found.000 folder (Something like lost+found folder from linux?) that was hidden by default, so I didn't spot it in the explorer.
Trying to take ownership of that folder... Worked for for files in there, safe for one - found.000\dir0000.chk$Txf; no idea what it is, and frankly neither do I care really.
Now... Me, coming from the Linux ecosystem, bang my head hard against the table whenever I get "Permission denied" as an administrator on the machine.
Most of the times... While doing something not very typical like... Rooting around (Hah... rooting... Get it?! I... Carry on) the Windows folder or system folders elsewhere. I can so-so understand why even administrators don't have access to those files.
But here, it was what I would consider a "common" situation, yet I was still told that my permissions were not high enough.
Seeing that it was my sister's PC, I didn't want to install anything that would let me gain system level permissions... So I got to writing a little forloop to skip the one hidden folder alltogether... That solved the problem.
My question is - Wtf? Why? How do you guys do this sort of stuff daily? I am so used to working as root and seeing no permission denied that situations like these make me loose my cool too fast too often...
Also - What would be the "optimal" way to go about this issue, aside for the forloop method?
The exact two commands I used and expected to work were:
takeown /F * /U user /S machine-name /R
icacls * /grant machine-name\user:F /T6 -
I don't understand wtf is happening today..
- in project A, terraform suddenly decided to stop working with kubernetes-related providers -- the CA cert mismatch error. I agree, it should be not working, because there are 2 kube-api severs behind an LB. But why now??? Why was it working for the last 2 months, until NOW????
- in project B, terraform suddenly decided to stop working _correctly_ with kubernetes-related providers -- it doesn't find resources randomly, even though they are available and I can see them via kubectl get. TF_LOG=DEBUG shows terraform sending correct requests to the kube-api, but the response is a 404. wtf... I see those resources present in another terminal window, only using kubectl. wtf....
- my PR in github was commented, I wanted to ask a question seconds later, and I'm getting a 502 from GH
wtf... I can't spot a pattern and that drives me freaking crazy.
Is this the Friday's curse...? IDK4 -
WHO CAN SPOT THIS STUPID PHP ERROR!
$string = "something.com"
if(strpos(".", $string))
echo " yep, there's a period";
else
echo "nope, fuck you there isn't";
output: "nope, fuck you there isn't"
me: wtf ??? fucking wasting my time on this fucking stupid tiny fucking error, goddamnit and each refresh takes 15 seconds because it involves calling all these apis from localhost, gmail, etc. arggg...
...for an hour, until I smacked my head so hard I'm in the hospital for a concussion
I hate when that happens.
Time to take a break.15 -
Last week I was working on a web development assignment (php and bootstrap).
I had a few problems but the most annoying was that bootstrap didn't want to apply to one specific element.
I sat there, looking for the error for about 2 hours. When I finally found it I was raging inside. I mistyped a - instead of an = after the class attribute (i.e. class-"Foo").
The mistake was hard to spot because of a combination of the font and the low screen resolution - 2 hours wasted because of that shit -
!rant, more of an incredulous/cruelly amused "you had ONE job..."
so: biggest IT/PC/electronics store in my (and neighboring) country. their webpage, of course with the function to buy online, because of course.
the big green "Buy" button does nothing. doesn't work. doesn't react. I keep clicking it multiple times, shorter, longer, etc, because maybe their JS scripts are just shit so they slow.
nope.
okay. open devtools, JS console.
hover over the button: "Error: isMobile is not a function".
click the button: "Error: isMobile is not a function"
WAT.
search for isMobile in the script.
173 occurences.
fuck this.
console: isMobile = function(){return false;}
because I'm not on my phone.
click the "Buy" button.
works flawlessly.
...HOW?
THE WHOLE PAGE IS AN ESHOP YOU COMIC RELIEF INCOMPETENTS! =D
173 uses of non-existing function that blocks business-critical feature, THE ONLY CORE FEATURE FOR WHICH YOUR SITE EVEN EXISTS, and NOBODY, not the dev who fucked it up, NOT EVEN QA, noticed it??? =D =D
if I was the boss of the devs, or even boss of the whole company...
git blame
...and then i'd go the whole chain from the dev who caused the bug, through all of the QA people who "tested" that version before deploy, and I would personally, on the spot, fire each and every single one of them.
mainly because of who knows how much money this stupid not even a proper bug lost them.
but secondarily, because clearly none of those people give a single shit (n)or have an idea how to do their jobs.
=D =D
yeah but I was a good guy, filed a bug report in the "Complaints" section of their Contact form.
it goes to some call-center-like peon, so it starts with a sentence "forward this to your site's dev people outright to file as a bug, thank you".
but... HOW.... =D
HOW can you let something like this through? =D
the bottleneck of your whole user interaction, which forms first of the three steps OF THE MAIN AND MOST IMPORTANT FUNCTION of your whole business... =D
...I...
...does not compute =D
...BUT THEY USING ANGULAR, SO THEY ALL MODERN AND HIGH-TECH AND EVERYTHING'S FINE!!! =D =D1 -
So as part of my news years resolution, I thought id build an app and I thought I would build it in vue.js and native script with a shared codebase, I've started with a fresh project and already I have an error, one that I've not caused, this is in router.js. see if you can spot it.
module.exports = (api, options) => {
require('@vue/cli-plugin-router/generator')(api, {
historyMode: options.routerHistoryMode
};
export default new Router(options);
}
When I've fixed the syntax error, I then get, the error:
/src/router.js: 'import' and 'export' may only appear at the top level (5:0)
This is when I run "npm run serve:ios"
if anyone has encountered this, please let me know how you fixed this.2 -
Ok. I GIVE UP! ...for at least a couple hours...
I'm not a big believer in... well anything suitable to the literal definition of believe. But there's only so much 'wtf? How is this even possible?' and any answer u can come up with is nearly statistically impossible...
I am a neuro-atypical (and just extremely atypical even if i somehkw was neurotypical) being, based on logic, finely calculated statistical probability and the most raw data and as unbiased as realistically possible, algorithms and interpretation (usually recursive pattern recognition with several highly detailed historical sources.
...but at some point statistical improbability and a collation of separate, yet relatively closely occuring events/circumstances makes logic, itself a primary suspect of corruption.
What was the breaking point that caused me to (temporarily) give up and tell logic to f off for a bit cuz maybe the illogical and mythical is the real logic, leaving me in a losing battle with 'the' fates?
Trying to get all my sourcing/purchase orders in/paid for/on the literal boats b4 end of the workday/week in china...
1st, had to drop a supplier cuz they have limited reps. When the one ive had 7+ years left, i got the aloof blonde girl societal trope of a rep... who for the 2nd time (despite the several very blunt complaints above her, incl me) she sent out a promotional update to the entire client list (ie, inherently competitors) as CC not BCC... over 200 business email accounts with tailored info of their sourcing.
2- totally diff company/ industry a former rep i was glad be rid of apparently just sfarted back for "awhile" as i needrf to restock/scale...apparently she forgot everything we discussed at length... lke if you want a chance on my business im not gonna be wasting time looking through your gui "mini store to then inquire about everything individually insead of a simple spreadsheet(which i print and put in a 3-ring binder rotating current catalogues in the same format i require everywhere)
3.dog was an ahole, my packed schedule got delayed and morphed.. a bunch of little bs thatd normally have no extra thought impact, hyperfocused forgetting one of my alarms til i realised my idiopathic fever was back and i didnt take/apply meds (pain/muscle relaxers mainly so despite this odd free time and needing to shower. I gotta sit on my rear, leg elevated/non-productive far 40min b4 i can shower (as functional legs and lack of syncope is almost a req to shower)
4. A new-ish rep of a company/factory i like/respect enough to not mention in relation... he makes invoice 1.. slight error thst was easily resolved...#2 was flawless... he goes to officially generate the contract(alibaba... verrrry simple with lots of extra explanation buttons). Price and all items match, its near workweek end so i was waiting for it so i could quickly pay/have it on the boat b4 it left and few fdav days are behind...
I put in card info, get to the 2 cbeck boxes (imo should be only 1 but whatever) asking if billing address is same ss delivery(its always default yes)... then i see a few lines in chinese (i can read enough for business negotiations... typical words/sentences innately look different than things like individual letters/address and postal indicators.) After a few loops of double checking, mentally trying to dismiss my i Intial judgement cuz it'd be too ridiculous... even resorted to google .... nope... initial wtf was spot on... recipient name/address was indeed the company(multi factory producer)i was purchasing a wholesale, via sea freight, bulk of products from.
Im pretty sure the system would've flagged it as an invalid contract within an hr... but seriously... ive been handling alibaba (and other) international sourcing since before high school(mainly small businesses i made sites/little tools for that found anything with a light up screen intimidating) and a purchase then shipment to the originating company/factory actually entered into a contract(the form is sooo simple)... im faced with ridiculously improbable obstacles actually existing and changing in such nonsensical statistically improbable ways so often that 1. I wouldn't trust a dr (or most humans) that didnt 1st assume i was crazy of some form...unfortunately im not, despite hkw much simpler and probable itd be 2. Id be super suspicious/converned if statistic norms were my norm for over a day.
But seriously wtf???
Someone give me some wisps of a frame of ref here... where's a typical 'fuck this, im out!' Breaking point?1 -
That second when you scan the stack trace, spot the line in error and just think to yourself "wtf just happened"