For one thing: don’t bother with fancy log destinations. Just log to stderr and let your daemon manager take care of directing that where it needs to go. (systemd made life a lot easier in the Linux world).

Structured logging is overrated since it means you can’t just do the above.

Per-module (filterable) logging are quite useful, but must be automatic (use __FILE__ or __name__ whatever your language supports) or you will never actually do it. All semi-reasonable languages support some form of either macros-which-capture-the-current-module-and-location or peek-at-the-caller-module-name-and-location.

One subtle part of logging: never conditionally defer a computation that can fail. Many logging APIs ultimately support something like:

if (log_level >= INFO) // or <= depending on how levels are numbered
    do_log(INFO, message, arguments...)

This is potentially dangerous - if logging of that level is disabled, the code is never tested, and trying to enable logging later might introduce an error when evaluating the arguments or formatting them into the message. Also, if logging of that level is disabled, side-effects might not happen.

To avoid this, do one of:

• never use the if-style deferring, internally or externally. Instead, squelch the I/O only. This can have a significant performance cost (especially at the DEBUG level), which is why the API is made in the first place.
• ensure that your type system can statically verify that runtime errors are impossible in the conditional block. This requires that you are using a sane language and logging library.
• run your testsuite at every log level, ensure 100% coverage of log code, and hope that the inevitable logic bug doesn’t have an unexpected dynamic failure.

From my experience, Cinnamon is definitely highly immature compared to KDE. Very poor support for virtual desktops is the thing that jumped out at me most. There were also some problems regarding shortcuts and/or keyboard layout I think, and probably others, but I only played with it for a couple weeks while limited to LiveCD.

ReplaceFile exists to get everyone else’s semantics though?

It’s because unicode was really broken, and a lot of the obvious breakage was when people mixed the two. So they did fix some of the obvious breakage, but they left a lot of the subtle breakage (in addition to breaking a lot of existing correct code, and introducing a completely nonsensical bytes class).

I’ve only ever seen two parts of git that could arguably be called unintuitive, and they both got fixes:

• git reset seems to do 2 unrelated things for some people. Nowadays git restore exists.
• the inconsistent difference between a..b and a...b commit ranges in various commands. This is admittedly obscure enough that I would have to look up the manual half the time anyway.
• I suppose we could call the fact that man git foo didn’t used to work unintuitive I guess.

The tooling to integrate git submodule into normal tree operations could be improved though. But nowadays there’s git subtree for all the people who want to do it wrong but easily.

The only reason people complain so much about git is that it’s the only VCS that’s actually widely used anymore. All the others have worse problems, but there’s nobody left to complain about them.

Python 2 had one mostly-working str class, and a mostly-broken unicode class.

Python 3, for some reason, got rid of the one that mostly worked, leaving no replacement. The closest you can get is to spam surrogateescape everywhere, which is both incorrect and has significant performance cost - and that still leaves several APIs unavailable.

Simply removing str indexing would’ve fixed the common user mistake if that was really desirable. It’s not like unicode indexing is meaningful either, and now large amounts of historical data can no longer be accessed from Python.

Unfortunately both of those are used in common English or computer words. The only letter pairs not used are: bq, bx, cf, cj, dx, fq, fx, fz, hx, jb, jc, jf, jg, jq, jv, jx, jz, kq, kz, mx, px, qc, qd, qg, qh, qj, qk, ql, qm, qn, qp, qq, qr, qt, qv, qx, qy, qz, sx, tx, vb, vc, vf, vj, vm, vq, vw, vx, wq, wx, xj, zx.

Personally I have mappings based on <CR>, and press it twice to get a real newline.

The problem is that there’s a severe hole in the ABCs: there is no distinction between “container whose elements are mutable” and “container whose elements and size are mutable”.

(related, there’s no distinction for supporting slice operations or not, e.g. deque)

True, speed does matter somewhat. But even if xterm isn’t the ultimate in speed, it’s pretty good. Starts up instantly (the benefit of no extraneous libraries); the worst question is if it’s occasionally limited to the framerate for certain output patterns, and if there’s a clog you can always minimize it for a moment.

Speed is far from the only thing that matters in terminal emulators though. Correctness is critical.

The only terminals in which I have any confidence of correctness are xterm and pangoterm. And I suppose technically the BEL-for-ST extension is incorrect even there, but we have to live with that and a workaround is available.

A lot of terminal emulators end up hard-coding a handful of common sequences, and fail to correctly ignore sequences they don’t implement. And worse, many go on to implement sequences that cannot be correctly handled.

One simple example that usually fails: \e!!F. More nasty, however, are the ones that ignore intermediaries and execute some unrelated command instead.

I can’t be bothered to pick apart specific terminals anymore. Most don’t even know what an IR is.

Even logging can sometimes be enough to hide the heisgenbug.

Logging to a file descriptor can sometimes be avoided by logging to memory (which for crash-safety includes the possibility of an mmap’ed file, since the kernel will just take care of them as long as the whole system doesn’t go down). But logging from every thread to a single section of memory can also be problematic (even without mutexes, atomics can be expensive and certainly have side-effects) - sometimes you need a separate per-thread log, and combine in the log-reader tool.

I don’t remember the last time I used ctrl-C. It’s always select or "+y.

I haven’t managed to break into the JS-adjacent ecosystem, but tooling around Typescript is definitely a major part of the problem:

• following a basic tutorial somehow ended up spending multiple seconds just to transpile and run “Hello, World!”.
• there are at least 3 different ways of specifying the files and settings you want to use, and some of them will cause others to be ignored entirely, even though it looks like they should be used.
• embracing duck typing means many common type errors simply cannot be caught. Also that means dynamic type checks are impossible, even though JS itself supports them (admittedly with oddities, e.g. with string vs String).
• there are at least 3 incompatible ways to define and use a “module”, and it’s not clear what’s actually useful or intended to be used, or what the outputs are supposed to be for different environments.

At this point I’m seriously considering writing my own sanelanguage-to-JS transpiler or using some other one (maybe Haxe? but I’m not sure its object model allows full performance tweaking), because I’ve written literally dozens of other languages without this kind of pain.

WASM has its own problems (we shouldn’t be quick to call asm.js obsolete … also, C’s object model is not what people think it is) but that’s another story.

At this point, I’d be happy with some basic code reuse. Have a “generalized fibonacci” module taking 3 inputs, and call it 3 ways: from a web browser on the client side, as a web browser request to server (which is running nodejs), or as a nodejs command-line program. Transpiling one of the callers should not force the others to be transpiled, but if multiple of the callers need to be transpiled at once, it should not typecheck the library internals multiple times. I should also be able to choose whether to produce a “dynamic” library (which can be recompiled later without recompiling the dependencies) or a “static” one (only output a single merged file), and whether to minify.

I’m not sure the TS ecosystem is competent enough to deal with this.

The problem is that what everybody really wants is parameterization, not concatenation. But most solutions therefor are flaky even if they exist.

and I already explained that Union is a thing.

That still doesn’t explain why duck typing is ever a thing beyond “I’m too lazy to write extends BaseClass”. There’s simply no reason to want it.

Then - ignoring dunders that have weird rules - what, pray tell, is the point of protocols, other than backward compatibility with historical fragile ducks (at the cost of future backwards compatibility)? Why are people afraid of using real base classes?

The fact that it is possible to subclass a Protocol is useless since you can’t enforce subclassing, which is necessary for maintainable software refactoring, unless it’s a purely internal interface (in which case the Union approach is probably still better).

That PEP link includes broken examples so it’s really not worth much as a reference.

(for that matter, the Sequence interface is also broken in Python, in case you need another historical example of why protocols are a bad idea).

Aside: Note that requests is sloppy there, it should use either raise ... from e to make the cause explicit, or from None to hide it. Default propagation is supposed to imply that the second exception was unexpected.

In practice, Protocols are a way to make “superclasses” that you can never add features to (for example, readinto despite being critical for performance is utterly broken in Python). This should normally be avoided at almost all costs, but for some reason people hate real base classes?

If you really want to do something like the original article, where there’s a C-implemented class that you can’t change, you’re best off using a (named) Union of two similar types, not a Protocol.

I suppose they are useful for operator overloading but that’s about it. But I’m not sure if type checkers actually implement that properly anyway; overloading is really nasty in a dynamically-typed language.

All of these can be done with raw strings just fine.

For the first pathlib bug case, PATH-like lookup is common, not just for binaries but also data and conf files. If users explicitly request ./foo they will be very upset if your program instead looks at /defaultpath/foo. Also, God forbid you dare pass a Path("./--help") to some program. If you’re using os.path.dirname this works just fine.

For the second pathlib bug case, dir/ is often written so that you’ll cause explicit errors if there’s a file by that name. Also there are programs like rsync where the trailing slash outright changes the meaning of the command. Again, os.path APIs give you the correct result.

For the article mistake, backslash is a perfectly legal character in non-Windows filenames and should not be treated as a directory component separator. Thankfully, pathlib doesn’t make this mistake at least. OTOH, / is reasonable to treat as a directory component separator on Windows (and some native APIs already handle it, though normalization is always a problem).

I also just found that the pathlib.Path constructor ignores extra kwargs. But Python has never bothered much with safety anyway, and this minor compared to the outright bugs the other issues cause.