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Lix Development

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(Technical) development of Lix, the package manager, a Nix implementation. Please be mindful of ongoing technical conversations in this channel.141 Servers

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14 Apr 2026
@piegames:flausch.socialpiegames
In reply to @Ericson2314:matrix.org
Well for an AFNix channel
This is the Lix development channel, where people involved with the Lix codebase can discuss their operations and issues. Please put more consideration into your communication
10:28:22
@raitobezarius:matrix.orgraitobezariusdone, tysm for investigating10:32:44
@rootile:flausch.socialRutile joined the room.21:20:41
@commentator2.0:elia.gardenlegacy_rootile -> @rootile:flausch.social changed their display name from Rutile (rootile) to legacy_rootile -> @rootile:flausch.social.21:42:36
15 Apr 2026
@shalokshalom:kde.orgShalokShalom In case someone is interested into arguments why semantic versioning is broken in itself, listen to Rich Hickey. 13:15:02
@shalokshalom:kde.orgShalokShalom * In case someone is interested into arguments why semantic versioning is broken in itself, listen to Rich Hickey. 13:15:14
@piegames:flausch.socialpiegamesOff-topic, please13:20:12
@xokdvium:matrix.orgSergei Zimmerman (xokdvium)Is Lix going to go with a zygote fork helper?18:15:09
@xokdvium:matrix.orgSergei Zimmerman (xokdvium)To mitigate the slow fork times?18:15:48
@raitobezarius:matrix.orgraitobezariuswell, lix has already very fast fork times now18:16:45
@raitobezarius:matrix.orgraitobezariusbut vfork is dangerous18:16:49
@raitobezarius:matrix.orgraitobezariusso if we can have the speed and the safeness (aka zygote fork helper), that'd be great18:17:02
@raitobezarius:matrix.orgraitobezariusbut lower priority18:17:05
@xokdvium:matrix.orgSergei Zimmerman (xokdvium)How did you achieve that? It's using the plan old fork() if I read the code correctly and that's still slow when there is a lot of memory allocated18:19:58
@raitobezarius:matrix.orgraitobezariusvfork18:20:51
@raitobezarius:matrix.orgraitobezarius grep inVFork 18:21:03
@raitobezarius:matrix.orgraitobezariusin the codebase18:21:04
@raitobezarius:matrix.orgraitobezarius
/**
 * runs a callback in a vforked child process that shares its address space with
 * the current process. the child behaves much like a thread as a result and the
 * callback must not make changes to process memory that we cannot undo from the
 * parent, otherwise we may leak memory or fully trash the parent address space.
 *
 * NOTE: see `asVFork` for safety information regarding credentials and signals.
 *
 * throws an exception if the child exec's or otherwise doesn't return a result.
 */
static auto inVFork(int flags, auto fn)
{
    auto [pid, result] = asVFork(flags, fn);

    if (result) {
        return std::move(result->value());
    } else {
        throw Error("vfork child unexpectedly did not produce a value");
    }
}

this is the entrypoint of the magic

18:21:26
@raitobezarius:matrix.orgraitobezariussome plain old fork() might be used in other places18:21:43
@xokdvium:matrix.orgSergei Zimmerman (xokdvium)Ah that's for the sandboxing setup, I see. I was looking at libexec helpers18:21:50
@raitobezarius:matrix.orgraitobezariusbut wrt to derivation builds, the overhead is around 2µs ?18:21:59
@raitobezarius:matrix.orgraitobezariusgetting lower would be nice ofc18:22:44
@raitobezarius:matrix.orgraitobezariusbut not urgent18:22:49
@raitobezarius:matrix.orgraitobezariusit is now possible to build 1M derivations reasonably18:23:00
16 May 2024
@aciceri:nixos.devzrsk joined the room.13:54:49
@samrose:matrix.orgsamrose
In reply to @lunaphied:lunaphied.me
I think there were a few CLs on the Gerrit but nothing being actively worked
The other thing that I could do if it helps is test things and try to find bugs. I did do some C++ work in the past, but may lack the time to do it justice here at least for about 30 days or so
15:55:29
@qyriad:katesiria.orgQyriadwe are not in any rush 🙂17:20:53
@samrose:matrix.orgsamroseWould it help to also test out the existing Lix code and try to find issues/bugs etc?17:23:21
@qyriad:katesiria.orgQyriadabsolutely17:23:41
@samrose:matrix.orgsamrose
  • how do people feel about the existing test suite that comes along with nix source code or Lix?
17:23:48

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