| 9 Aug 2021 |
 andi- | But those Symbols aren't tracked by the GC? Otherwise we should set an allocator for them. | 18:55:10 |
 manveru | i don't know how C++ works unfortunately :( | 18:55:47 |
| andi- | They are allocated once and stay there until the process terminates | 18:56:16 |
| manveru | my assumption was that this std::string thing does an allocation that needs to be cleaned up again afterwards | 18:56:26 |
| andi- | I has to be cleaned up but that happens then the entire symboltable goes out of scope | 18:57:01 |
| andi- | With C++20 (and GCC 11) we could make use of Heterogeneous lookup for unordered containers (http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p0919r3.html) for the lookup using the std::string_view... so far that isn't possible without huge effort AFAICT. | 19:53:17 |
 nixinator | In reply to @manveru:matrix.org
i don't know how C++ works unfortunately :( even c++ programmers don't know how it works ;-) | 22:46:36 |
 pamplemousse | I am trying to compile nix a non nixos (ubuntu) using clang.
I am using nix develop .#nix-clang11Stdenv (thanks to https://github.com/NixOS/nix/pull/4996) , but I get plenty of errors when linking src/libutil/libnixutil.so
/nix/store/qvc6cz5d43jhhm4a3r48xkrc82xh1s95-binutils-2.35.1/bin/ld: src/libutil/libnixutil.so.p/archive.cc.o: in function `nix::dump(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, nix::Sink&, std::function<bool (std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)>&)':
/src/nix/build/../src/libutil/archive.cc:73: undefined reference to `std::allocator<char>::allocator()'
[... and many more…]
Feels like the flake.nix might be missing stdlib, but I tried adding libcxx without success, and libstdcxx5 fails to build.
| 23:52:00 |
| 10 Aug 2021 |
|  anubhavkini left the room. | 05:51:17 |
 Las | What is the point of the GitHub fetcher? I tested the speed difference compared to the Git fetcher and it wasn't so different. | 12:34:16 |
 sterni | I think it performs much worse for big repos | 12:35:20 |
| Las | In reply to @sternenseemann:systemli.org
I think it performs much worse for big repos I tested it on Nixpkgs lol | 12:39:23 |
| Las | Though perhaps it was because I had already fetched an earlier commit? | 12:39:43 |
 niksnut | The github fetcher is way faster than git. | 12:42:25 |
| niksnut | Often it's even faster in cases where git can do an incremental fetch. | 12:43:18 |
| sterni | In reply to @pamplemouss_:matrix.org
I am trying to compile nix a non nixos (ubuntu) using clang.
I am using nix develop .#nix-clang11Stdenv (thanks to https://github.com/NixOS/nix/pull/4996) , but I get plenty of errors when linking src/libutil/libnixutil.so
/nix/store/qvc6cz5d43jhhm4a3r48xkrc82xh1s95-binutils-2.35.1/bin/ld: src/libutil/libnixutil.so.p/archive.cc.o: in function `nix::dump(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, nix::Sink&, std::function<bool (std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&)>&)':
/src/nix/build/../src/libutil/archive.cc:73: undefined reference to `std::allocator<char>::allocator()'
[... and many more…]
Feels like the flake.nix might be missing stdlib, but I tried adding libcxx without success, and libstdcxx5 fails to build.
have you tried llvmPackages_11.libcxxStdenv? | 12:44:42 |
| Las | In reply to @niksnut:matrix.org
The github fetcher is way faster than git. Do you think there are any ways of making the Git fetcher faster? | 12:45:15 |
| sterni | also these usually use binutils' ld.bfd which sometimes causes weird problems linking C++, so pkgsLLVM.stdenv may be worth a try which uses lld | 12:46:35 |
| sterni | * pamplemousse: also these usually use binutils' ld.bfd which sometimes causes weird problems linking C++, so pkgsLLVM.stdenv may be worth a try which uses lld | 12:46:45 |
| niksnut | Quick test: fetching github:NixOS/nixpkgs => 16.5s, git+https://github.com/NixOS/nixpkgs => 131.5s, doing the latter again => 11.3s | 12:48:54 |
| niksnut | Fetching git+https://github.com/NixOS/nixpkgs?shallow=1 => 85.2s | 12:52:31 |
| niksnut | That's probably the best we can do with git. | 12:52:54 |
| Las | Hmm, thanks | 13:00:40 |
| Las | The issue is you can't check commit signatures when using the github fetcher | 13:01:01 |
| Las | In reply to @niksnut:matrix.org
Fetching git+https://github.com/NixOS/nixpkgs?shallow=1 => 85.2s I tried this on my own machine, and it did indeed take ages (so long I interrupted it), but time git clone git://github.com/NixOS/nixpkgs --depth 1 took 10.31 seconds according to time. | 13:31:10 |
| Las | Are you sure something isn't broken in the Git integration in Nix? This is an extreme difference. | 13:31:53 |
| niksnut | In reply to @Las:matrix.org
I tried this on my own machine, and it did indeed take ages (so long I interrupted it), but time git clone git://github.com/NixOS/nixpkgs --depth 1 took 10.31 seconds according to time. Yes, that's what ?shallow= does. | 13:32:06 |
| niksnut | hm | 13:32:18 |
| Las | I wonder why it takes so long then | 13:32:20 |
 balsoft | BTW I can confirm that Nix' fetcher is way slower than fetching manually | 13:32:38 |
