You are constantly ignoring the main point: There’s a simple solution for today’s requirement, and there’s a complicated solution that will also solve a future, not existing yet, requirement. Chet want to write the later, not the former.

The complicated solution is trying to solve two problems at once, and one of them does not exist yet. It’s speculative.

> The fact that the author just chooses to not even try to check if Chet is correct or not should be a red flag.

Chet himself says that the thing will be necessary 3 weeks from now, implying that it’s not necessary today.

You can anticipate changes and plan for it. You can brainstorm it. You can even question the current requirements. What you don’t do is solving something that does not exist.

When we say YAGNI, that means the problem you’re stating, even when reasonable by itself, does not apply to the current context. It’s easier to revise a simple design later when needed, than refactoring a complex one that have a flawed assumption.

I think you're missing the point of the poster you are replying to. You make it sound like 3 weeks is 3 years. It ain't.

Very little, or possible nothing at all, is going to change in 3 weeks. If you are that myopic - as the XP people were - then constant failure is not going to be surprising. It will be expected.

It’s not about the specific timeframe. It’s about something that has no value for today’s context superseding something that do. It’s ok to anticipate changes, it’s not ok to act as if they’re already here when it’s clear that they’re not.

And the other axis is the lean towards complexity.

Let’s say you need to add logging for a web app to be able to quickly troubleshoot it. The design was to create a simple module that printf to stderr. But then the dev comes to you with a new complicated design involving elastic search and what not, saying that we will need it in 3 weeks to dissect the logs, etc. It may have been a good idea, but it’s not valuable. The correct idea is to put that on the backlog, not to start writing code for it.

Implementing complicated idea takes more time than implementing simple idea, while the value is the same.

When there’s a need for having something elastic search for the logs, it will be easy to refactor the simple code that we have than fixing the possibly flawed implementation that would have resulted if we went with the complex design.

> It’s about something that has no value for today’s context superseding something that do.

But this is incorrect. Chet is saying "if we interpret today's requirement this way, what we do today has no value, if we interpret today's requirement this other way, what we do today has value". (and if he is in fact not saying that, the problem is that you and the author have no idea if he was saying that or not, you just saw "3 weeks" and concluded, incorrectly, that it is not about today's requirement)

Please check my other comment for an illustrative example.

> Implementing complicated idea takes more time than implementing simple idea, while the value is the same.

That is factually not true. Take my illustrative example of my other comment: Day 1 requirement has ABSOLUTELY NOT VALUE if the devs that implement it don't listen to someone who said "in Day 5, we will be in this situation, so Day 1 requirement has only values if done this way and not that way".

> Let’s say you need to add logging for a web app to be able to quickly troubleshoot it. ...

Your example does not prove anything. We here all agree that over-engineering is a bad idea, and we can all come up with example where it is done.

What you need to do, is to demonstrate that ignoring what we already know for sure will happen in 3 weeks will never be less efficient than taking 5 minutes to pick the correct solution between two simple solutions, one compatible with in 3 weeks and one not.

This is how you demonstrate. If you say "f(x) is always positive", the demonstration is not to present some x values that are positive, the demonstration is to find a way to show that there is no x values for which f(x) is negative. If you restrict yourself to "let's assume that Chet solution to be compatible with the situation in 3 weeks is complex and will not be needed", of course you will conclude what you conclude. What you need to do is to convince us that it is impossible to have a situation where the information of what will be in 3 weeks will never be useful.

Because this is the point: in the situation in the article, the author has not enough information to know if Chet solution is complicated or not something needed. In fact, according to Chet, it is something needed, and the simple solution has therefore __zero value__.

> Chet is saying "if we interpret today's requirement this way, what we do today has no value, if we interpret today's requirement this other way, what we do today has value".

He is certainly not saying that. The premise is that the simple thing has value for today, the complicated thing has value for today and in 3 weeks time.

> than taking 5 minutes to pick the correct solution between two simple solutions, one compatible with in 3 weeks and one not.

The choice is between a simple solution that will solve today’s issue and a complicated solution (which will take more time) that will also solve an hypothetical situation in 3 weeks.

> in the situation in the article, the author has not enough information to know if Chet solution is complicated or not something needed.

The premise of the article is that the solution is indeed complicated and not something needed today. You may have also been in similar situation. You don’t invalidate an argument by pointing that the premise isn’t true when there’s no argument made that it will always hold true.

Saying that P imply Q, does not mean P is always true.

Let me answer to your 2 comments here.

My criticism against YAGNI as a sane approach is not that things cannot be out-of-scope or over-engineered. My criticism against YAGNI is that it teaches developers to be unable to see a situation and think "yeah, maybe it's a bad over-engineering thing, or maybe it is not". It teaches devs to read __everything__ as bad over-engineering.

In your comment, you are showing exactly that. If you are not "contaminated" by YAGNI, you will look at the situation as described and not jump to the conclusion that "the premise is obviously that ...".

Here, you are saying "He is certainly not saying that". But if you look exactly what he is saying in the dialog, he MAY be saying that, but he also MAY NOT. This is my criticism: YAGNI trained you to misinterpret.

In your other comment, you say that Chet ask for developing something for "a powerful engine as the user may like to go offroad with a trailer". Where this even come from? Are you really unable to mentally conceive, in your head, a simple situation where Chet is talking about the exact motor that was planned from the start?

You are saying that Chet is talking about a motor for going offroad with a trailer, and yet, in the article, Chet says "but in 3 weeks that will be insufficient so since we’re going to need this" followed by "You don’t understand. We’re definitely going to need it. See, here’s an example…" followed by "But we really are…".

And at no point, absolutely no point, you thought "wait, maybe Chet is not being excited by a crazy hypothetical situation, maybe Chet is just talking about something ... we are really going to need it ... because it is in today's project goal, because it is just written that it is what we need to build and what the users are asking for".

You keep saying "the premise", but "the premise" is my criticism. I understand that the author is presenting the situation as if Chet is getting out of scope and uselessly complex. My criticism is that in the described situation, the author should recognised that this premise is just an assumption, and that he should ask for more information.

Maybe another example to illustrate. "Hello, my name is Bill, and I really think it's a bad idea to put wall paint in food. Let's take this situation, my friend Bob is coming to help me to cook, and he says "oh, I think it would be better if this birthday cake was more colorful". I immediatly said "Nope, No way", I knew he wanted to add wall paint in the cake. Bob said "maybe we can go to the shop and get ...". "No" I interrupted him. I would not go to the DYI shop to buy wall paint, it's ridiculous."

According to you, you are saying "well, it is the premise of the article that Bob want to use wall paint in the cake". But beyond the premise, this article still shows that Bill has a totally useless and strange reaction: normally, Bill should not have jumped to the conclusion that Bob want to put wall paint in the food.

Well, this conversation with you is a good illustration of why YAGNI is a terrible idea. In this whole conversation, you really struggled even conceive a situation where someone like Chet will use the same language but will not want to replace the project motor for another one to do offtrail with a trailer, but was simply talking about the motor that was planned all along in the project.

Unfortunately, because of YAGNI, there are more and more devs that are unable to see useful discussion without jumping on the conclusion that the whole discussion should be discarded.

> You keep saying "the premise", but "the premise" is my criticism. I understand that the author is presenting the situation as if Chet is getting out of scope and uselessly complex. My criticism is that in the described situation, the author should recognised that this premise is just an assumption, and that he should ask for more information.

There’s a premise that you know can be true. There’s a logical reasoning that you don’t seem to be against. There’s also a conclusion that you also don’t disagree in your comments.

If the whole thread is you arguing about the premise and saying there may be a chance of it not being true, then this is not a discussion. It’s speculative fiction.

> If the whole thread is you arguing about the premise and saying there may be a chance of it not being true, then this is not a discussion. It’s speculative fiction.

But it is a really concrete question. Me or other people may be in Chet's situation, so it is important that you just not answer "if you are not over-engineering, then it's a different premise, so it does not count, you don't really exist".

We both agree that over-engineering is bad. I guess you agree that sometimes, someone may propose a different solution that is not over-engineering? My question, and it is not a trick question, is: can you explain me what this person should do in this situation.

It is not a trick question, it is real: my impression from this discussion is that if I'm in a situation where I have a constructive proposal, not out-of-scope, totally within the project goal, that will help the situation reaching its goal more smoothly, then whatever I say, you will just answer me "you ain't gonna need it", the same way the author did to Chet.

Let's imagine that Chet is speaking to the author of the article, and let's imagine that Chet does not want to plan for a new offroad motor pushing a trailer. Let's imagine that Chet is talking about the current project, its exact current goal, that within this project, they plan to use a standard Sedan 500 pounds engine, and that Chet is charged by the author of the article of installing wheels, but that the author has chosen a simplistic approach and that, as a consequence, these wheels will not be able to support a 500 pound engine. For example, the author of the article has asked Chet to do a "simple-on-axle-mounting" approach, and that car engineers have demonstrated that for more than 400 pounds engine, you need a more complex "double-corkscrew-mounting" (I made this up of course). Installing the wheels is the current task, and installing the engine will happen in 3 weeks. How can Chet approach the author of the article?

In the article, Chet approach the author by saying "I could do this simplistic thing now but in 3 weeks that will be insufficient so since we’re going to need this more complicated thing I want to do it now". What should have he said instead? Why this sentence is bad and what make this sentence sounds like Chet is talking about something out of scope? The author does not know that the "simple-on-axis-mounting" approach is discredited. What in this simple sentence informs the author of the article that Chet is not trying to inform them that this approach is not correct and that he is instead talking about out-of-scope over-engineering?

Trying to answer your question.

Your example does not work with the article because the simplistic approach is already proven to be an ok design. The wheel will support the engine. The complex approach (maybe a non standard suspension) is for an hypothetical scenario that Chet believes will occur in 3 weeks. That scenario is not the mounting of the engine which is already planned and scoped.

You don't delay a project because of an hypothetical scenario. What you do is evaluate and present the risks and a possible solutions. You don't rush in the implementation unilaterally. That's a cowboy mindset.

> What in this simple sentence informs the author of the article that Chet is not trying to inform them that this approach is not correct and that he is instead talking about out-of-scope over-engineering?

  I could do this simplistic thing now

That means the solution is OK and the implementation will provide some value for the customer.

  but in 3 weeks that will be insufficient

How does he know that? Where's the argument, not merely examples as in the rest of the dialogue, but real objective facts and numbers (like there's another requirement that the customers are pressing us). It's very likely that any such situation would have skipped past by when designing the simple approach.

  so since we’re going to need this more complicated thing 

Will we really need it? We know that we don't need it today. What will change in a few week that will make it a requirement? Again what needed here is objective facts. Not what-if scenarios.

  I want to do it now

Why the rush? Why can't it wait for 2 weeks when we can tie the feature to the name of few customers (assuming it's B2B) or market analysis. Why do we need to spend let's say a week on this complicated approach when we can solve the problem in a day or two and ship it.

That's all the questions I would have asked if I was not familiar with the project. But if you're the project lead, the only thing that would have led you to question yourself is if Chet has said the simplistic approach does not work. But it does.

> Your example does not work with the article because the simplistic approach is already proven to be an ok design.

Where is it done? No where in the article the author said "Chet said it will not work in 3 week, so I demonstrated that it will work in 3 weeks". The author just __assume__ it is an ok design.

What I'm telling you is that you and the author are acting in a way that shut down the conversation in case you are right AND in case you wrong.

Your answer to that is "I'm mentally impossible to conceive a scenario where the author missed something, did not realise the 'simple-one-axle-mounting' approach will fail". That is such a red flag.

> The complex approach (maybe a non standard suspension) is for an hypothetical scenario that Chet believes will occur in 3 weeks.

This is not what I ask you. I ask you to say what Chet should say in the situation where Chet is right, where the author design is incorrect and Chet scenario is not hypothetical. You keep twisting back "no but let's just pretend it cannot happen". This is my worry: are you even able to conceive that it can happen?

> That means the solution is OK and the implementation will provide some value for the customer.

What? That is definitively not how normal people would understand this sentence. Are you a native english speaker? According to you "I could do this simplistic thing now but it would not work" is an impossible sentence? Or that this sentence is saying that the solution is OK because the sentence contains "I could do this thing"?

> How does he know that?

Well, that's the point. In this step of this dialog, you don't know yet, and yet you already concluded that Chet does not know and that you know.

> Where's the argument, not merely examples as in the rest of the dialogue, but real objective facts and numbers

Chet is introducing the problem, he is shut down before he can even give his first example. Chet may have plenty of objective facts and numbers, but the author shut down the conversation before it even happen. In this dialog, Chet is __trying__ to bring facts and numbers, starting by a concrete illustration, but he is interrupted before he can do it.

You are so full of it. You are saying "Chet did not arrive and slap the author with a book full of facts, so it is the proof that Chet has no idea of what he is talking about and should be shut down before he can prove this assumption is wrong".

> Will we really need it?

You don't know if you really need it or not, you don't know if Chet has facts and numbers. Because YAGNI is shit, you just assumed that the situation is over-engineer, while you have no idea of what the situation is and stop people who try to explain it to you.

> We know that we don't need it today.

No you don't. You just stop Chet explaining and interrupt him.

> What will change in a few week that will make it a requirement? Again what needed here is objective facts. Not what-if scenarios.

This is what I saying from the start: when Chet reacts like that, the fact that the author does not say "wait a minute, do you have objective facts" is a red flag. The fact that the author goes to the what-if scenario that his design will obviously work, without providing any objective facts, is the problem.

> Why the rush?

Where is there any rush. The situation is extremely simple. The guy say: "hear me you, I think I will be wasting me time doing this". The author answers "shut up" and __assume__ that Chet has no argument.

> That's all the questions I would have asked if I was not familiar with the project. But if you're the project lead, the only thing that would have led you to question yourself is if Chet has said the simplistic approach does not work. But it does.

I saw very experienced devs failing at that all the time. In this article, the author is assuming he has a good understanding of the project and shut down anyone who can bring important information.

Your approach: "I'm the lead, so I cannot be wrong, so I assume Chet is incorrect when he said the simplistic approach will not work" is so bad. Do you even realise that?

You are a perfect example of what I was talking about. What would you have lost in just hearing Chet out? But now, YAGNI is just shit, it pushes people to have this attitude to assume that only them know the truth.

> According to you "I could do this simplistic thing now but it would not work" is an impossible sentence?

Because that’s not what it said. If someone is talking to me, I don’t invent sentences in my head for them and assume things that they haven’t said.

That’s what you’re doing, inventing a whole situation outside of what the author described because you keep adding things that the author has not mentioned.

I have my interpretation of the dialog. And I agree with the author that Chet should focus on the simple thing now, and je can always wait later to refactor it to handle the future situation.

If you want to discuss an alternate interpretation, do it within the confine of the dialog. Don’t add your own words to it.

> Because that’s not what it said.

What it said is "I could do this simplistic thing now but ... that will be insufficient"

It LITERALLY says that it will not work, that it is not a good solution.

Even if Chet is wrong in his prediction, you quoted Chet and pretended that this thing that Chet is saying is a proof that this solution will work. This is so obviously not at all Chet's opinion.

And I'm sure you are going to INVENT "but Chet does not know what will happen in 3 weeks". Firstly, again, your "proof" is a quote from Chet, who, according to you, demonstrate that this solution is ok while that sentence is used by Chet to explain that the solution is not ok. But secondly, you have no idea why Chet is saying what he is saying, you INVENT that Chet does not know, does not have facts and numbers, while there are tons of real life example where it is easy and correct to predict that in 3 weeks something will not work anymore.

> ... inventing a whole situation outside of what the author described ...

I don't.

In the situation described by the author, is it true, is it factual that Chet thinks it will not work: YES, he is saying exactly that.

Is it factual that Chet is trying to provide more information but the author shut him down before hearing them: YES, this is factual.

Your only little argument is "let's imagine that Chet proposal, that he NEVER explains because he is interrupted, is bad". All I'm saying is that you have no idea what Chet argument is, you just assumed. This is fact. Can you tell me where, factually, in the written dialog, Chet explain his understanding and this understanding is indeed incorrect? Can you point me to these sentences? They don't exist.

You see "3 weeks" and concluded that "it is out of scope and/or over-engineered", which is obviously a bad conclusion as it is very easy to find plenty of example where this conclusion is totally wrong.

I don't want an alternate interpretation, there is no need for it. Does the author shut Chet down before Chet explains himself? YES. There is nothing to interpret, it's just a fact. Then, based on that, you said things that are BS, such as "Chet said '3 weeks' so it is the proof that it is out-of-scope". I then gave you a counter-example showing that your reasoning is wrong, and your only argument was "you invented this example so it does not count".

> What it said is "I could do this simplistic thing now but ... that will be insufficient"

> It LITERALLY says that it will not work, that it is not a good solution

You have a strange definition of insufficient.

> Can you tell me where, factually, in the written dialog, Chet explain his understanding and this understanding is indeed incorrect

Both the author and I never said that the complicated thing is wrong or incorrect. YAGNI is basically saying “not now”. Meaning we can revisit when the situation calls for it, but not today.

YAGNI is a matter of priority and resources allocation. You don’t solve problems you don’t have or unlikely risks.

Do you set up a cold room in your house and buy food for the next month because you know you will be hungry then? No. You buy a fridge and groceries for the next few days. Not because a catastrophic event can’t happen, but because your budget is limited and/or you have better things to do with that money.

Complicated things cost more than simple things (to build and maintain) and take longer to ship and produce value. The only reason to not go with simple thing is when it does not work, not when it’s insufficient. We already know it does not handle every little feature, but it will work for now.

> You have a strange definition of insufficient.

You have a strange definition of "okay". "Insufficient" is definitively not okay. The definition of "insufficient" is "less than needed". How is that "okay"? And if it is not "okay", than, yes, it is not a good solution.

Thank you to demonstrate that people who pushes for YAGNI are delivering "insufficient" work and think it is "okay".

> Both the author and I never said that the complicated thing is wrong or incorrect. YAGNI is basically saying “not now”. Meaning we can revisit when the situation calls for it, but not today.

And you have no idea if the situation calls for avoiding the problem today or not today. Take back the car example: if you install wheels that are incompatible with the planned engine, you need to fix this problem __today__.

Your code will fail in 3 week because of a mistake you are making TODAY. The proof: if you install the correct wheels today, then nothing will fail in 3 weeks. The failure that will happen in 3 weeks (and it will happen: car engineers have tested it and are clear on that, it is the law of physics) is not due to a problem that was born in 3 weeks, the failure will be due to the bad decision made today. This is a TODAY problem.

Your reasoning is totally crazy, imagine if it was considered seriously: "oh, you noticed a bug in my code during code review. Well, let's ship the code in production and wait for users to raise a bug ticket, because before then, the problem does not exist".

> YAGNI is a matter of priority and resources allocation. You don’t solve problems you don’t have or unlikely risks.

And in the case of Chet, you have prioritized NOTHING. You still have no idea of what Chet was raising. You have no idea of what are the risks. You have no idea if your current plan is even the correct plan or not.

Imagine the following situation: "oh, we took the wrong road, if we continue tomorrow we will arrive in Berlin instead of Paris". Only very stupid people will say "no, that's a problem for tomorrow, let's just spend all the time in between doing something totally useless that we will need to undo tomorrow".

> You buy a fridge and groceries for the next few days.

You realise your contradiction here: you are saying you buy TODAY food for when you will be hungry IN THE NEXT FEW DAYS. According to your logic, you should not do that. What you should do is to go to the shop every single time you feel hungry and buy only one item, the one you want to eat now.

> Complicated things cost more than simple things (to build and maintain) and take longer to ship and produce value. The only reason to not go with simple thing is when it does not work, not when it’s insufficient.

Simple things that have no value at all cost more than complicated things. When Chet come up, he is saying "hey, I think I notice we are planning to build something that has absolutely no value". Your reaction is "no, it is better to do something useless with no value than something more complicated that has value".

And again, as I guess you will not get it: maybe Chet is wrong. The problem is that you just ignore Chet. Maybe he is wrong, but maybe he is right, you have absolutely not idea.

> We already know it does not handle every little feature, but it will work for now.

It will not work for now. If you install the wrong wheels on a car, the car is useless until you install the engine.

The important thing is not "the task of today", it is to deliver what the user needs. Here, Chet is saying that he thinks you are planning to build something that is a waste of time, something that will not deliver what the users need.

The reaction should be "Chet, maybe you are right, but maybe you are wrong, let's check together". Instead, the reaction was to interrupt him and act as if the users care about today's work more than the real product.

The whole car example is flawed because insufficient does not mean wrong or incorrect.

> And in the case of Chet, you have prioritized NOTHING. You still have no idea of what Chet was raising. You have no idea of what are the risks. You have no idea if your current plan is even the correct plan or not.

Why are you so sure the author cannot compare <complicated thing> and <simple thing>? Or he has not considered <complicated thing> before even Chet and discarded it?

> When Chet come up, he is saying "hey, I think I notice we are planning to build something that has absolutely no value"

You’re again inventing stuff. The simple thing has value today. It will be insufficient in three weeks. It is not insufficient today. If we implement it, the user will have a working solution way sooner instead of waiting for the complicated thing to be ready.

How do you value your user’s time?

> The important thing is not "the task of today", it is to deliver what the user needs.

What the user needs today and what it will need in three weeks are different things. You and Chet have been ignoring the user’s need for today.

If someone wants some data outside of a system and you can write a quick perl script in 30 minutes to produce a CSV, you do it. You don’t argue about setting up a whole ETL pipeline because that will be needed in 3 weeks and the perl script is insufficient. Especially when that pipeline will take days to implement. You can have a whole set of examples and what not. But we can discuss that after the perl script is written and the needed data is exported.

> The whole car example is flawed because insufficient does not mean wrong or incorrect.

In the car example, the solution proposed by the team leader is insufficient. The result is that the solution proposed by the team leader will lead to either the project to fail or to a waste of money.

> Why are you so sure the author cannot compare <complicated thing> and <simple thing>?

What are you talking about? I'm not saying you cannot compare <complicated thing> and <simple thing>, I'm saying that the author does NOT COMPARISON: he has no idea what Chet is talking about, because Chet want to explain and the author shut him down.

You cannot say that Chet's solution, which is more complicated, is less valuable than the simple solution, because you don't even know if the simple solution has any value.

> The simple thing has value today.

No, YOU DON'T KNOW THAT. You invent that. Take the car example: having a wheel but no engine has no value. There are ton of other examples: for example, if someone is talking about a bug that occur because in three weeks we are in 2026 and that the code has a bug that make the code unusable if the year is 2026. If the product is released in February 2026, then the simple thing has zero value. (that's a made-up example for the sake of simplicity, but having bad design that destroy the quality soon after is a real thing, very common)

> How do you value your user’s time?

And how do you value users leaving because in 3 weeks that see the product is not able to do something they were expecting?

> What the user needs today and what it will need in three weeks are different things.

You don't know that. In the example of the car, the user don't need a 1 wheel car with no engine.

Again, because you have no idea what Chet is talking about, you have no idea if what Chet is talking about impacts today's users.

> blablabla ETL blablabla

You keep giving example where someone over-engineer (or ask for working on something too early, or ask to work on something out of scope, or ask to adapt the current goal based on hypothetical future goal, ...). EVERYONE HERE agrees that this is bad and should be avoided. The disagreement is that in the dialog in the article, the author did a terrible job at assessing if Chet contribution was a good or a bad thing (based on these criteria), because the author has drunk the YAGNI cool-aid and jumped to the conclusion it was a bad thing while there are plenty of situations where Chet will act exactly like that when it is not some of these bad things.

(and again, my criticism is not these "bad" things are not bad and should not be avoided, my criticism is that some devs say "YAGNI" and shut down the contributions that are fully relevant to do a good job and deliver value. A simple solution is to not be an obnoxious d*khead and just listen to Chet, to check if it is a real bad thing or not, and act accordingly like an adult instead of behaving like a little kid)

PS: I note that you just ignore elements where you cannot answer. (for example, the food that you don't buy one item at the time, the fact that "prioritization" means nothing when you don't even know between what and what you are prioritizing, ...)

> In the car example, the solution proposed by the team leader is insufficient

Because you created that situation out of the blue. And you’ve been ignoring any case where both solutions do work, but one is more complicated than the other. And the simple one can be delivered very soon, but the complicated one will be useful only three weeks later,

> if someone is talking about a bug that occur because in three weeks we are in 2026 and that the code has a bug that make the code unusable if the year is 2026. If the product is released in February 2026

But the simple thing can let us deploy in 2025 and land a big contract before the holidays. Perfect is the enemy of good as we say.

> Again, because you have no idea what Chet is talking about, you have no idea if what Chet is talking about impacts today's users

It is explicitly mentioned that the complicated thing will only matter in 3 weeks, not today.

> You keep giving example where someone over-engineer. EVERYONE HERE agrees that over-engineering is bad and should be avoid.

And you keep ignoring that time matters and a problem in the future doesn’t mean it exists right now. You do the thing that matters for today, then you do the thing that matters for next week.

Your argument has been the thing that matters for today may not really matter and that is not what Chet has been saying.

  I could do this simplistic thing now but in 3 weeks that will be insufficient

Insufficient in 3 weeks only matters if we can’t ship the simple thing in that timeframe. If we can do so in one or 2 days, we can then focus on the complicated thing.

And that’s assuming Chet knows more about the project constraint than the project leader. Something my be great technically, but the other perspectives that the leader have is why he is refuting it. Like he got an email this morning that we will be abandoning the project in 3 weeks but we’re contractually obligated to fix every bug. He can’t discuss that with you, but he can direct your workflow.

So the next time you hear YAGNI, ask why. Don’t rush to prove your point.

What you say if not making much sense. You don't provide counter-arguments or arguments, it looks more like a collection of special cases, but they don't contradict anything I'm saying. It's like if I say "f(x) = x - 10 can be negative, for example if x = 2" and you just say "no because sometimes x = 15". I don't get the point of your argument, you seems to say that if you find one special case that works for your conclusion, then your conclusion is correct.

For example, you just say "what if the simple thing can let us deploy in 2025 and land a big contract before the holiday". Firstly, it's a weak example, do you really believe that someone will sign a big contract with you on brand new code within 3 weeks of the release without either testing for few weeks or asking guarantee that it will still work after 3 weeks? Secondly, it's easily a bad point for your approach, what do you think will be the commercial impact when the partner will see that your code falls apart after 3 weeks because you did not anticipated something they find obvious? Thirdly, a simple tweak and it becomes an example against your approach, what if the big contract is on week 4, and that you miss it because you have to undo the simple solution and build the more complicated solution in order to have a product that work? But more importantly, it does not contradict anything I said, my approach still is better: if you have a big contract, then LISTEN TO CHET, and if what he says can wait, just say "great, noted, but we will do it after the big contract" (and if Chet has a good point, you will win bigger).

I really don't understand your point: listening to Chet has only good consequences. You listen to him, and then you still can decide if it's smarter to do it now or not.

For all the scenarios that me and you have proposed, your method keep failing my scenarios, while my method keep succeeding my scenarios AND your scenarios.

You also are hypocritical: on one hand, you hand-wave "perfect is the enemy of good" and on the other, you whine "bouhou, if we try to stay aware of the constraints that are coming our way, this is soooo baaad, we need to stay pure and perfect, this is sooo important".

About "today's user": users don't care about the code. If the plan is to work on the backend on day X and on the front-end on day X+3weeks, the fact that the code runs on day X is a negative for the user, today's user, because today's user cannot use the backend, he needs the backend and the frontend. And because you built a backend incompatible with the front-end, you will deliver even later. Another illustration is about the car example: today's user don't care about a one wheel structure without an engine, this is totally useless for them. If you successfully install the wrong wheel today, you impacted negatively today's users, because they will get their car even later.

About "time matters": you are arguing that, but you are pushing for a solution that WASTES time. Your logic is "installing the wrong wheel takes 5h, installing the correct wheel takes 10h, so let's install the wrong wheel". Except that the user will not be able to use the final product until the correct wheel has been installed, so you will use 5h to install the wrong wheel, 5h to uninstall the wrong wheel, 10h to install the correct wheel, and you will have spent 20h instead of 10h. And I know your argument, which is "I'm not talking about the car example, in my scenario, today's task is a feature that users can use directly". But my argument is that you are shit at knowing if it is the case or not. You read this article, you saw the author shutting down Chet, and not one instant you thought "ok, but of course this is terrible advise if we are in a car-example situation". I looks like this possibility flew high above your head, as I need hours of exchange to educate you on the subject.

About "you keep ignoring that ... a problem in the future doesn’t mean it exists right now": You saw "3 weeks", and you are mentally unable to realise that because the code is running today, it does not mean that the code is delivering what it is supposed to deliver. A simple example: the task is to install wheels that are compatible with the planned engine, and the team leader planned to install the wrong wheel. Someone notices and say "in 3 weeks, when we install the engine, it will not work". This is not a future problem: you have failed TODAY'S REQUIREMENT, TODAY'S TASK. The task itself requires that what you build is compatible with what will be built in 3 weeks. But because you saw "it will not work in 3 weeks", then you concluded that what you have built today satisfies the requirements. It is sometimes the case, it is sometimes not the case. And because you did not let Chet talk, you don't know what he is talking about, so you don't know if he is talking about a future problem or you having failed today's task in a way that will only be visible in 3 weeks.

About "assuming Chet knows more about the project constraints than the project leader": YES. NO ONE. NO. ONE. No one knows the project perfectly. No one will never miss something. When Chet is coming to the team leader and says "I think we may be wrong", listen to Chet. If Chet is incorrect, fine, no harm done. But Chet may not be incorrect. The team leader does not know what they don't know, they should never assume that they know more about the project constraints than the other collaborators.

And again, because I'm sure you have difficulties wrapping your head around this: I don't ignore that not all project are like a car construction. The problem is that your arguments are incompatible with a common situation. The fact that your arguments are not incompatible with some situations does not mean they are correct. The fact that they fall apart in some situations means they are incorrect.

Your argument is always about:

  We need to to task X today, we're going to do Task Y later. But we need both task X and task Y to complete the whole project. But the solution for task X is wrong because it conflicts with task Y. And when we get to task Y, we won't be able to deliver. And Chet know this. But the author don't want to listen to Chet, and the author is wrong for that.

While the situation is:

  The project is already defined. There's task X to be done, and we have settle on a solution A for it. Chet is the one who will be implementing it. Chet uncovers a situation that leads him to believe that the solution B is better because of a constraint that will come in effect in 3 weeks. He says that he can implement A, but because we're going to need B in 3 weeks, let's scrap A and go with B instead. Now the author knows both A and B (and maybe B was discussed beforehand but Chet don't knows about it),and says that B don't matter, A is good enough.

  Instead of asking why, Chet decide to argue for the validity of B. The author reiterates that B doesn't matter. At the end Chet decides to walk away. And never wanted to learn why A is the better choice when B seems to be perfect.

I was Chet at one time and never have someone like the author to rein me in. I get cured from wanting to implement complicated solution when client asked me for demos and I couldn't show anything because I was trying to solve everything. And you're right, they don't care about code. They care about working product, and today, not in 3 weeks. So between A and B, I deliver A first, then worry about B.

And when someone higher than you (and better placed to have more information about the constraint of the project) refuses your idea. You ask why, you don't immediately try to prove your position. Imagine doing that in the army.

> While the situation is

BS. You have no idea if it is the case, you don't listen to Chet. You __assume__ that Chet's solution is motivated by a different goal, but you __shut him down before he said so__.

You now invent things that are never described in the scenario, to try to badly justify that somehow the author's ASSUMPTION is justified. But the problem is that even if what you said happened, the author's assumption is still an assumption: the author is a bad lead for not verifying at 100% that Chet is indeed talking about the same B that the author has in mind. And even if the author does it behind the scene, the author is a bad lead for not being fully aware that he should have writing this step explicitly within the scene, as it is a crucial step for the judgement and should be evaluated before acting as he did.

> Now the author knows both A and B

The author SHUT CHET DOWN BEFORE Chat explains what he is talking about. How does the author even know that Chet's complicated solution correspond to B?

I guess you will say "but Chet told him behind the scene" or a bad argument like that. Which is of course changing the scenario as described in the article (something you were incorrectly whining about but have no problem doing it yourself).

But also it justifies my criticism: even if Chet's explanation happened behind the scene, it means that when you read this scenario, instead of thinking "oh, red flag, the author should make sure he understands exactly what Chet is talking about", you just __jumped to the conclusion__ that this situation was a "constraint from a hypothetical future" situation where what you had behind your eyes gave you no indication it was. And you __invented__ without any justification, that elements that are not within the scene occurred just to justify a posteriori your conclusion.

To take a more extreme example: it is like if the article says "and then this black person is arrested", and when someone says "it is strange, I don't understand on which basis this person was arrested", and someone says "well, when reading the article, I just assumed that the black person is a thief and that they saw it behind the scene". This last person reading of the article has highlighted his prejudice, his bias. Same here: you ignored the possibility that it may be a "Task X vs task Y" situation because you __blindly assumed__ it is the situation that YAGNI has put in your head.

> and maybe B was discussed beforehand but Chet don't knows about it

And maybe the unicorns have whispered to the author's ear what Chet was talking about.

You are so full of shit, you are just making excuses and grasping straws to pretend that the terrible judgement of the author was somehow justified behind the scene. Do you even realise that?

> I was Chet at one time ...

I am not surprised at all. But the problem is that not everyone is as bad developer as you are: sometimes, they found __proper problem__. In the exact dialog, the author shuts Chet down before he can explain the problem. Chet even said "you don't understand ...", trying to say to the author that what he is bringing is not what the author seems to understand it is. That in itself should give you pause: "wait, are we sure Chet is not trying to talk about a problem that the author genuinely missed", but it did not because you were unable to mentally conceive it may be the case.

> And when someone higher than you (and better placed to have more information about the constraint of the project) refuses your idea. You ask why,

Again, if you are a team leader and you think that you will never miss anything or that you are the only ones in position to discover things that has been missed, then you are such a shit team leader. With a fragile ego.

> Imagine doing that in the army

WTF? What kind of argument is that? Your argument seems to boil down to "reSPecT my auTHorItaaa". As a team leader, I am smarter than that: I know that sometimes things will be missed, and I know that it is better for everyone to be in a situation where anyone can bring it to attention.

And, yes, sometimes they will bring to my attention things I already know. But I listen to them first. It does not change ABSOLUTELY ANYTHING, and if someone says the opposite, this person is full of shit and does not know what they are talking about.

YAGNI means you ain’t gonna need it. And if you can’t ask why A stays and B can’t be accepted, that just means you believe your reasoning is always the correct one, and your team leader is an wrong to not accept it.

And as I’ve said. If you state something and the person in front doesn’t accept it, you ask for his reasons. You don’t rush to prove yours.

You really can’t accept that the author knows about B and have a valid reason to not choose it, evenk if B is completely valid? Software engineering is all about tradeoffs. And it’s on the leaders to choose some, even if you really believe it must lean the other way.

> There’s a simple solution for today’s requirement, and there’s a complicated solution that will also solve a future, not existing yet, requirement.

There are tons of examples that show that your reasoning is incorrect.

Let's invent one: you need to build a car. Day 1: put the front left wheel on the frame structure. Day 2: put the front right wheel on the frame structure, Day 3: put the back left wheel on the frame structure, Day 4: put the back right wheel on the frame structure, Day 5: attach that particular motor on the frame.

Now, you are on Day 1, and Chet arrive and say "this wheel will not do, it will never support the motor that we need to install on day 5".

You are telling me that what Chet said is to be ignored because "it is a requirement for day 5". But it is not. What Chet has done is not bringing a requirement of day 5 into day 1, what Chet has done is that it has noticed an incorrect interpretation in Day 1 requirement. The requirement for Day 1 should have been read as "put the front left wheel on the frame structure, but of course, it goes without saying, use a wheel that is compatible with the car we want to build".

You saying that because Chet is using Day 5 information, the point he is making is not about Day 1 requirement is incorrect.

The thing is: Day 1 requirement and Day 5 requirement don't live on their own. Hell, your job is not to "just do Day 1 requirement" and it has never been. No one, absolutely no one, want a frame structure with just one wheel and no motor.

In the article, Chet does that: he tries to send the message "this is the point of the work, we will need it, it is what we plan to build, so you need to take that into account in today's requirement interpretation. If you don't account for it, you better not even do today's requirement".

And, and let me be clear on that, maybe the element that Chet brings will end up being not relevant or not needed. But the problem is that neither you or the author know that yet, and you reject the discussion before you can even discover if it's the case or not. The problem is that author and you just saw "Day 5" or "in 3 weeks" and, because YAGNI is a terrible advance, jumped on the conclusion "it is in the future, so it has nothing today with today's requirements".

(oh, and in practice, the people who says "YAGNI" will then say "well, the problem is Day 1 requirement, each requirement should go into excruciating details to re-explain the whole point of the work, should think of all the possible interpretation and should be written by someone who know better than me how to build the implementation to each line of code, but somehow should waste their time explaining the project to someone less competent".

Again, the problem with this argument is that the solution of "use your brain, build things carefully" creates a way easier and elegant solution than YAGNI+ridiculously unrealistic requirements.)

This is where the disagreement comesfrom. You have a different interpretation of requirements. A requirement is not a list of tasks. It’s a set of needs and constraints that drive a design.

In your example, the general goal could be to do a small sedan car, but then Chet come in and say that we need a more powerful engine as the user may like to go offroad with a trailer. And he’s ready to cancel the order for the standard engine and ready to adjust the chassis, the frame,… for the new engine.

But the thing is that there is no such requirement in the design, no hard data that says that user would like such data. It’s just anticipating needs without proper market research.

And as I’ve said previously, it’s okay to explore design for a more complete solution. It’s not okay to commit to them with just an emphasis on the benefits, nit the cost of maintenance while there’s no value to the business.