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Joined 1 year ago
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Cake day: June 25th, 2023

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  • 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.





  • Obviously the actual programs are trivial. The question is, how are the tools supposed to be used?

    So you say to use deno? Out of all the tutorials I found telling me what tools to use, that wasn’t one of them (I really thought this “typescript” package would be the thing I was supposed to use; I just checked again on a hot cache and it was 1.7 seconds real time, 4.5 seconds cpu time, only 2.9 seconds if I pin everything to a single core). And I swear I just saw this week, people saying “seriously, don’t use deno”. It also doesn’t seem to address the browser use case at all though.

    In other languages I know, I know how to write 4 files (the fib library and 3 frontends), and compile and/or execute them separately. I know how to shove all of them into a single blob with multiple entry points selected dynamically. I know how to shove just one frontend with the library into a single executable. I know how to separately compile the library and each frontend, producing 4 separate artifacts, with the library being dynamically replaceable. I even know how to leave them as loose files and execute them directly (barring things like C). I can choose between these things all in a single codebase, since there are no hard-coded project filenames.

    I learned these things because I knew I wanted the ability from previous languages I’d learned, and very quickly found how the new language’s tools supported that.

    I don’t have that for TS (JS itself seems to be fine, since I have yet to actually need all the polyfill spam). And every time I try to find an answer, I get something that contradicts everything I read before.

    That is why I say that TS is a hopelessly immature ecosystem.




  • 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.




  • 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.