No, it is not cheap, generally.

Example:

Dendrite[0] was going to be a Rewrite of Synapse (which was a prototype which ended up going into production). The rewrite started more than 5 years ago, had lots of development breaks and it still is nowhere complete or close to replace a existing Synapse instance (which even today is ... Well ... suboptimal software).

The current plans are to support and use both servers long term, because Synapse is already too widespread.

I wouldn't call that cheap.

[0]: https://github.com/matrix-org/dendrite

Well starting from scratch for a rewrite is generally a bad idea. I'm more a fan of incremental re-wrties. But I have code bases I have been working on for years with tens of thousands of lines where basically the entire thing gets rewritten ever 18 months or so, a bit at a time.

Isn't your example proof of the benefit of pragmatic coding? Synapse is actually serving users right now. Dendrite sounds like a "better design" which is stuck in purgatory.

They tried an incremental rewrite before. They failed, and started Dendrite.

https://matrix.org/blog/2020/10/08/dendrite-is-entering-beta

Survivor bias.

You don't see all the perfectly designed codebases that never went anywhere.

We only talk about legacy code because it's the one that pays the bills.

Are you the only working on the codebase? It may be easy to rewrite your own codebase, but it's certainly not easy to rewrite someone else's. Especially if they haven't been caring about code quality and/or test coverage.

My definition of "good-quality" code is pretty much exactly "how difficult would this codebase be for a new engineer to understand and modify safely."

You can go really really fast when you don’t give a shit about consequences.

Often the worst code comes from prolific people. There’s just so much if it. And if you touch it you will break it at least 1% of the time, so you have to pick your battles when you are trying to keep the ratio under control.

If you write loosely-coupled code, it shouldn't be that easy to break things unless you're careless.

Nobody in this whole post is talking about loosely coupled code. If you find someone complaining about how hard it is to modify loosely coupled code, you have my permission to fire them.

For everyone else this is tautological. Good code can continue to be good code.

If it were loosely coupled it wouldn’t be an anecdote in this conversation. There is no “I”, there is no “you”. There is only “us”. I can only control Us so much, and I don’t have a time machine.

People who only have green field projects as their context are very frustrating in conversations like this. They make suggestions like, well, don’t fuck up in the first place. I don’t know what your history is but that’s the feeling I’m getting.

Not that it matters but I've worked on a mix of green-field projects and mature codebases in various domains with teams of various sizes over more than a decade of professional experience.

I could assume you're throwing shade on "prolific programmers" out of some sense of insecurity, but it wouldn't be fair to generalize about strangers on the internet ;)

No, It’s an overdeveloped sense of justice.

I just punch up at condescending people. Every discipline has a bunch of armchair people who don’t understand the problem who think “get more exercise” is the response to depressed people or people with chronic fatigue, “eat fewer calories” is the answer to weight issues or diabetes, or “write it right the first time” is a useful response to people trying to solve real world problems.

Kindly let the grownups talk and keep your flash card answers to yourself.

> Kindly let the grownups talk

Well one of us is certainly being condescending ;)

And did you really answer twice to the same comment? My goodness I must have really struck a nerve.

Well this escalated quickly

If everyone is discussing a problem that you don’t see, then why offer your simple solution except to appear smart? And who needs to appear smart? That’s your insecurity. Not mine.

Idk maybe it's because I did freelancing for quite some time and was often hired to clean up somebody's mess, but I think it's not so bad to rewrite someone else's code. What I normally do is quarantine the old code behind a clean interface, or else start fresh with a better code structure, and then copy and paste the good bits of business logic from the old project into the new one.

Code has a lot of really great properties which make it easy to modify in provably safe ways if you know what you're doing.

That really depends on what you're working on and to what degree it's coupled to the system it's a part of. A form on a web application, or an API endpoint? Sure, rewriting it is probably trivial. A new process scheduler for Linux? The caching system in an HTTP server? Maybe writing the code will be easy (though probably not), but building any confidence that it doesn't break something that's unexpectedly load bearing will be anything but cheap. And if what you're rewriting that started out as "just code and see what happens" it's going to be more expensive still.

Which isn't to say that rewriting can't be cheap, but some intentional design (or at least diligent maintenance and refactoring) must have gone into the system to support that style of development. At which point you're back to targeting "quality," even if it's no longer a focus of on the smaller scale.

How are defining cheep, and how big is the metaphorical house? Developer time is not free (unless you are working a personal project) and if an hour or two up front of planning things out stops you from making a lynch pin mistake that needs to be re-written it is better to do the planning.

If the amount of time that it takes to rewrite something is trivial (a week or less) then you aren't working on something all that big/complicated.