nandi/frq · flake.nix

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Build the client with Nix, not just a shell for it   1
# frq is Jolt source, so "building" it is three things, not one:
#   jolt        the runtime that reads it        (github:jolt-lang/jolt)
#   jolt-native libvidya and libjoltmoq, in Rust (gitlab:nandithebull/jolt-native)
#   frq         this tree, with its deps resolved to store paths
# Jolt resolves deps.edn by running git at startup, which a build sandbox has
# no network for — so every dep is fetched by Nix instead and handed back as
# a :local/root through -Sdeps.
#   nix build .#frq && ./result/bin/frq
# On a machine that is not NixOS the GL driver is the host's and the loader
# will not find it, so the window never opens ("GL display: argument does not
Find the host's GL driver when the store's is not the system's   16  # name a valid config"). The launcher handles that itself: off NixOS it hands
# the process to nixGL, which puts the host's driver ahead of the store's.
# Nothing extra to type, and a distrobox/container Arch is the same case as
# a bare one.
Build the client with Nix, not just a shell for it   20  description = "frq — a freeq client in jolt";
inputs = {
  nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
Take jolt and jolt-native as flakes, off my own fork   24    # `git+https` with `?submodules=1` rather than the github scheme: Jolt's
  # own flake declares `self.submodules`, which this Nix rejects when the
  # flake is fetched as `github:`. Its outputs are not what we take — the
  # runtime is built here, by joltFrom — but it is a flake all the same, so
  # its own inputs are locked with ours rather than left to float, and
  # `vendor/` comes along as the submodule the build needs.
Split the tree three ways, and let the phone be Flutter's   31    # The fork rather than jolt-lang/jolt, and unpinned: the desktop follows
  # the fork's main. It used to be paired with a second, pinned input for
  # the APK's boot image; there is no jolt APK now, so there is one runtime
  # and one rev.
Build the client with Nix, not just a shell for it   35    jolt-src = {
Take jolt and jolt-native as flakes, off my own fork   36      url = "git+https://gitlab.com/nandithebull/jolt?submodules=1";
    inputs.nixpkgs.follows = "nixpkgs";
Build the client with Nix, not just a shell for it   38
Take the Android objects from jolt-native's CI, always the latest   40    # The source half of jolt-native: the Jolt code under glimmer-backends/ that
Split the tree three ways, and let the phone be Flutter's   41    # binds the native objects, and the flake that builds them. This input is
Name the libcosmic recipe for its backend: `just cosmic run`   42    # what `just cosmic run` builds against.
Take the jolt-native ahead of the release, since a run can build it   43
Split the tree three ways, and let the phone be Flutter's   44    # It carries both backends that are left — glimmer-cosmic over
  # libjoltcosmic for the window, glimmer-tui over libjolttui for the
  # terminal — and no longer jvui or vidya, which were experiments.
Stop building the media plane frq no longer loads   47
Pin jolt-native at the merge rather than at the branch   48    # Pinned all the same, and pinned to a rev, because an
Pin the native half to the release the rest of the tree names   49    # unpinned `main` is a build whose native half is free to sit at a
  # different commit from the tree that talks to it. It did, and what the
  # drift cost was silence: the Jolt half sent a reaction pill's hover card
  # to a libvidya with no handler for one, and the pill said nothing.
Merge origin/main, and let one jolt-native answer for both backends   53    # It also carries the terminal backend — crates/jolt-tui, the same tree ABI
  # over a grid of cells, and jolt/glimmer-tui beside glimmer-vidya. That was
  # a second input at a second rev while it lived on a branch, which is the
  # drift this comment warns about wearing a different hat: one input, and
  # the window and the terminal are the same library either way.
Build the client with Nix, not just a shell for it   58    jolt-native = {
Take the jolt-native that opens a room where it means to   59      url = "git+https://gitlab.com/nandithebull/jolt-native?rev=8e8cd5192dc161b423c0ee5dd41a7a058b24b409";
Take jolt and jolt-native as flakes, off my own fork   60      inputs.nixpkgs.follows = "nixpkgs";
Paint the same screens into a terminal   61
Build the client with Nix, not just a shell for it   63    # The sha deps.edn pins, on the fork with the reconciler fixes.
  glimmer = {
    url = "git+https://gitlab.com/nandithebull/glimmer?rev=399df371c790d690fb6e4560c3d4d7f838502857";
    flake = false;
Find the host's GL driver when the store's is not the system's   68
  # Only ever used off NixOS, to put the host GL driver on the loader path.
  nixgl = {
    url = "github:nix-community/nixGL";
    inputs.nixpkgs.follows = "nixpkgs";
Bundle the closure into one file the AppImage runtime mounts   74
  # Wraps a closure into a single self-extracting file. Only the `appimage`
  # output evaluates it.
  nix-appimage = {
    url = "github:ralismark/nix-appimage";
    inputs.nixpkgs.follows = "nixpkgs";
Build the client with Nix, not just a shell for it   81
Split the tree three ways, and let the phone be Flutter's   83  outputs = { self, nixpkgs, jolt-src, jolt-native, glimmer, nixgl, nix-appimage }:
Build the client with Nix, not just a shell for it   84
    systems = [ "x86_64-linux" "aarch64-linux" ];
    forEachSystem = f:
      nixpkgs.lib.genAttrs systems (system: f nixpkgs.legacyPackages.${system});
Run this tree on a native half the builders made   88
    # Mesa, despite the name: it covers Intel and AMD alike. The NVIDIA
    # wrappers are the ones that need --impure (they read the host kernel
    # module's version), which is why this only ever reaches for Intel.
Stop carrying the 32-bit GL stack and half of git   92
    # Built from nixGL's default.nix rather than taken from its flake
    # outputs, for the one argument the flake hardcodes on: `enable32bits`,
    # which on x86_64 puts a second, i686 copy of mesa, its LLVM, and
    # intel-media-driver into the wrapper. frq is 64-bit on both halves —
    # the Rust cdylibs and the Chez runtime — so nothing here ever opens the
    # 32-bit driver, and carrying it is most of the dev shell's closure.
    nixGLFor = pkgs: (import nixgl {
      inherit pkgs;
      enable32bits = false;
    }).nixGLIntel;
Run this tree on a native half the builders made   103
Build the APK from the flake, at the rev flake.lock pins   104      # The Android SDK wants two things `nixpkgs.legacyPackages` cannot give:
    # `allowUnfree`, because the SDK's own licence is not free, and
    # `android_sdk.accept_license`, which is how you say so in a file rather
    # than at a prompt a build has no terminal for. Neither can be set on a
    # legacyPackages attribute after the fact, so this is a second import of
    # the same locked nixpkgs rather than a second nixpkgs.
    # This used to live in `just apk` as a `nix build --impure --expr` with
    # `builtins.getFlake "github:NixOS/nixpkgs/nixos-unstable"` inside it —
    # which fetched whatever nixos-unstable was that morning, not what
    # flake.lock pins, so the SDK under the APK and the nixpkgs under
    # everything else were free to drift apart. Here they are the same rev.
    androidPkgsFor = system: import nixpkgs {
      inherit system;
      config = {
        allowUnfree = true;
        android_sdk.accept_license = true;
    # Only the floor Gradle stands on. It installs build-tools and a platform
    # into ANDROID_HOME itself as it goes — see `just apk` for why that means
    # a writable copy — so composing more of them here buys nothing.
    # includeNDK = false deliberately: the app is Dart and path_provider is
    # platform channels, so there is no native code to need one, and asking
    # for it is a few hundred megabytes and a Gradle fetch of that exact NDK.
    androidSdkFor = system:
      let android = androidPkgsFor system; in
      (android.androidenv.composeAndroidPackages {
        cmdLineToolsVersion = "13.0";
        buildToolsVersions = [ "34.0.0" ];
        platformVersions = [ "35" "34" ];
        includeNDK = false;
      }).androidsdk;
Run this tree on a native half the builders made   140      # egui reaches for these with dlopen rather than linking them, so being
    # in the cdylib's buildInputs is not enough — whatever starts frq has to
Follow the xorg renames, and stop wrapping nix in distrobox   142      # put them on the loader path itself. Without libx11 here, vidya reports
Run this tree on a native half the builders made   143      # "X11 unavailable", falls back to Wayland, and winit refuses to build a
    # second event loop after the failed first one.
    # Out here rather than beside the package that first needed them: the
    # dev shell starts frq too, on this tree's source rather than the store's
    # copy of it, and a second copy of this list is a second chance for the
    # two ways of running to disagree about what the window needs.
    runtimeLibsFor = pkgs: with pkgs; [
      libGL
      libxkbcommon
      wayland
Follow the xorg renames, and stop wrapping nix in distrobox   154        libx11
      libxcursor
      libxi
      libxrandr
Run this tree on a native half the builders made   158        vulkan-loader
Build the client with Nix, not just a shell for it   160
    packages = forEachSystem (pkgs:
      let
        inherit (pkgs) lib;
Run this tree on a native half the builders made   166          nixGL = nixGLFor pkgs;
Find the host's GL driver when the store's is not the system's   167
Take the native objects from their own flake rather than rebuilding them   168          # libvidya (the retained-tree ABI glimmer-vidya binds, on egui),
        # libjolttui (the same tree over a grid of cells) and libjoltmoq (the
        # AV media plane) — one workspace, three cdylibs, taken from
        # jolt-native's own flake rather than rebuilt here.
        # This used to be a rustPlatform.buildRustPackage over the same
        # source, which meant restating upstream's build: the seven git deps
        # hashed by hand in `cargoLock.outputHashes` and re-hashed whenever
        # its Cargo.lock moved, the linuxHeaders path v4l2r's bindgen wants,
        # and a postPatch dropping the .cargo/config.toml that pointed the
        # build at DotSlash. Upstream's flake says all of that itself now,
        # and says it once. It also builds cpal with the `pipewire` feature,
        # which the restatement did not — so device names in a call are
        # PipeWire's rather than raw ALSA PCMs.
Paint frq with jvui, and take the last Rust out of the window   182          # libjolttui only. Not libjoltmoq, whose job `frq.av.plane` does
        # now, and no longer libvidya either: the window is jvui on SDL,
        # so the only object left out of that Cargo workspace is the
        # terminal backend, and only `just tui` loads it.
Switch frq.av onto the jolt media plane, and stop shipping libjoltmoq   186
        # This makes the closure smaller and the APK smaller. It does NOT
        # make the build shorter, and it is worth being exact about why:
        # jolt-native compiles its external crates ONCE, in a
        # `buildDepsOnly` derivation shared by all three objects, so
        # asking for two of them still builds every dependency the third
        # has — the 440 crates that are jolt-moq's alone. Getting those
        # out of the build is a change in jolt-native, not here: either
        # jolt-moq leaves that workspace, or its deps artifact stops
        # being workspace-wide.
        native =
          let np = jolt-native.packages.${pkgs.stdenv.hostPlatform.system};
          in pkgs.symlinkJoin {
            name = "jolt-native-ui";
Split the tree three ways, and let the phone be Flutter's   200              # Both backends there are. libjoltcosmic is the window —
            # libcosmic behind the same retained-tree ABI — and libjolttui
            # is the terminal. Neither is libvidya and neither is jvui:
            # those were experiments and are gone from this tree entirely.
            paths = [ np.libjolttui np.libjoltcosmic ];
Switch frq.av onto the jolt media plane, and stop shipping libjoltmoq   205
Build the client with Nix, not just a shell for it   206
Fetch libmoq_ffi again, and keep the codecs out of Rust   207          # libmoq_ffi — MoQ over QUIC behind UniFFI's C ABI, FETCHED rather
        # than built. This is the object `frq.moq.raw` is generated from.
Bind libmoq_ffi from the object's own metadata, not from its header   209
Fetch libmoq_ffi again, and keep the codecs out of Rust   210          # Fetched because building it is the thing this whole exercise is
        # about: moq-ffi pulls moq-native, iroh, quinn, rustls and aws-lc-sys
        # behind it, which is 440 crates that nothing else in this tree
        # needs. Upstream already publishes the object for both Linux
        # architectures, so we take those bytes.
Bind libmoq_ffi from the object's own metadata, not from its header   215
Fetch libmoq_ffi again, and keep the codecs out of Rust   216          # Pinned to a release and to a hash, and the hashes below are
        # upstream's own published .sha256 files rather than ones observed
        # here — a `nix-prefetch` of whatever the URL serves today would
        # record that it downloaded something, not that it downloaded the
        # right thing.
        # WHAT THIS BUILD IS NOT: moq-ffi's `audio` and `video` features are
        # on by default upstream and are OFF in these artifacts, so there is
        # no publish_audio/publish_video and no moqaudio*/moqvideo* here —
        # 206 functions where the Apple artifact has 230. That is why the
        # bindings are generated from the object (`just gen-moq`) and not
        # from the C header the release ships, which describes the Apple one.
        moqFfi =
            version = "0.3.17";
            target = {
              "x86_64-linux" = "x86_64-unknown-linux-gnu";
              "aarch64-linux" = "aarch64-unknown-linux-gnu";
            }.${pkgs.stdenv.hostPlatform.system};
            hash = {
              "x86_64-linux" = "sha256-dzQXpV4JgdtD+g33WX51FFAQdfCUXkNsx1xPbobPfUI=";
              "aarch64-linux" = "sha256-PdzRwbJFqOZWRgI0HHX2XUH+Ljh4V3jvQ9asfvCuIPA=";
            }.${pkgs.stdenv.hostPlatform.system};
          pkgs.stdenv.mkDerivation {
            pname = "libmoq-ffi";
            inherit version;
            src = pkgs.fetchurl {
              url = "https://github.com/kixelated/moq/releases/download/moq-ffi-v${version}/moq-ffi-${version}-${target}-libmoq_ffi.so";
              inherit hash;
            dontUnpack = true;
            # It carries no RUNPATH and needs libgcc_s, libm and libc — the
            # host's on an ordinary distro, and nothing at all on NixOS
            # unless they are bound here.
            nativeBuildInputs = [ pkgs.autoPatchelfHook ];
            buildInputs = [ pkgs.stdenv.cc.cc.lib ];
            installPhase = ''
              mkdir -p $out/lib
              cp $src $out/lib/libmoq_ffi.so
              chmod +w $out/lib/libmoq_ffi.so
Bind libmoq_ffi from the object's own metadata, not from its header   259
        # One directory for the loader to look in. jolt resolves every
        # :jolt/native name against JOLT_NATIVE_LIB, and the objects now come
        # from two places — jolt-native's flake, and the moq-ffi release — so
        # they are joined rather than the path being made a list, which the
        # loader does not take.
Bind the C libraries a call actually needs   265          # The C codecs, from nixpkgs. libmoq_ffi carries the transport and
        # nothing else — moq-ffi's `audio` and `video` features would have
        # brought Opus and H.264 with them, at the price of compiling a
        # 1062-crate workspace — so the codecs are linked here instead,
        # where they have always lived.
        # Named in :jolt/native, so the loader resolves them the same way it
        # resolves libvidya: by name, out of one directory.
        # A flat C face for openh264, because openh264 has none. Its
        # `ISVCEncoder` is `const ISVCEncoderVtbl*` — every method is a
        # function pointer in a vtable — and jolt.ffi cannot call one: Chez
        # fixes a foreign procedure's types when it compiles it, and the
        # target must be a literal C symbol name. So the vtable is walked in
        # c/frq_h264.c and jolt binds the five plain symbols it exports.
        # One translation unit against a library nixpkgs already has. It is
        # a calling convention adapter, not a second media plane, and the
        # distinction from the moq-ffi build it replaces is the whole point:
        # this compiles one .c file, not a 1062-crate workspace.
        frqH264 = pkgs.stdenv.mkDerivation {
          pname = "frq-h264";
          version = "0.1";
          src = ./c;
          nativeBuildInputs = [ pkgs.pkg-config ];
          buildInputs = [ pkgs.openh264 ];
          buildPhase = ''
            $CC -O2 -fPIC -shared frq_h264.c -o libfrqh264.so \
              $(pkg-config --cflags --libs openh264)
          installPhase = ''
            mkdir -p $out/lib && cp libfrqh264.so $out/lib/
        # openh264 is here for frqH264's DT_NEEDED; alsa-lib for capture
        # and playback. V4L2 needs nothing: it is ioctls against libc and
        # the kernel, so there is no library to name.
Split the tree three ways, and let the phone be Flutter's   302          # No SDL any more: it was jvui's, declared in jvui's own
        # :jolt/native and dlopened by soname. libcosmic paints through wgpu
        # and takes what it needs from `runtimeLibs` instead.
        codecs = [ pkgs.libopus pkgs.openh264 frqH264 pkgs.alsa-lib ];
Bind the C libraries a call actually needs   306
Let the plane take real devices, not only test thunks   307          # ALSA's PipeWire plugin, which is how `default` resolves to
        # anything on a machine running PipeWire — and every machine frq
        # targets does. Without it alsa-lib fails to dlopen
        # libasound_module_pcm_pipewire.so and the only devices that open
        # are raw hardware ones, which PipeWire is already holding.
        # An environment variable rather than a library in the join:
        # alsa-lib looks plugins up by directory, not by soname.
        alsaPluginDir = "${pkgs.pipewire}/lib/alsa-lib";
Bind libmoq_ffi from the object's own metadata, not from its header   317          nativeAll = pkgs.symlinkJoin {
          name = "frq-native";
Bind the C libraries a call actually needs   319            paths = [ native moqFfi ] ++ codecs;
Bind libmoq_ffi from the object's own metadata, not from its header   320
Build the client with Nix, not just a shell for it   322          # Jolt itself: Clojure on Chez, built the way its own flake builds it.
Split the tree three ways, and let the phone be Flutter's   323
        # Still a function taking its source, though there is only one of
        # them now: the second was the Bionic-addrinfo fork the APK's boot
        # image carried, and there is no jolt APK any more — the phone is
        # ClojureDart and Flutter, and jolt does not run there at all.
Build the APK from the flake, and from nothing   328          joltFrom = src: pkgs.stdenv.mkDerivation {
Build the client with Nix, not just a shell for it   329            pname = "jolt";
          version = "dev";
Build the APK from the flake, and from nothing   331            inherit src;
Build the client with Nix, not just a shell for it   332
          strictDeps = true;
          nativeBuildInputs = with pkgs; [ chez makeWrapper pkg-config xxd ];
          buildInputs = with pkgs; [ lz4 zlib ncurses openssl libuuid ];
          JOLT_VERSION = "dev";
          dontConfigure = true;
          buildPhase = ''
            runHook preBuild
            scheme --script host/chez/build-jolt.ss release target/release/jolt
            runHook postBuild
          installPhase = ''
            runHook preInstall
            mkdir -p "$out/bin"
            install -m755 target/release/jolt "$out/bin/jolt"
            runHook postInstall
          # jolt.deps shells out to git and unzip, and jolt.mvn-http dlopens
Stop carrying the 32-bit GL stack and half of git   354            # OpenSSL through the JOLT_OPENSSL_LIBDIR seam. gitMinimal rather
          # than git: all jolt.deps asks for is clone/fetch/rev-parse, and
          # the full package carries Perl and Python for the subcommands
          # written in them — a quarter of a gigabyte for git-send-email.
Read the clock in the reader's zone when /etc/localtime is a file   358
          # TZDIR so a zone *name* resolves wherever this runs: frq.clock
          # hands one to tzset, and glibc then looks for the tzfile under
          # /usr/share/zoneinfo unless told otherwise — which a NixOS host
          # does not have. The store's own tzdata is there on both kinds of
          # machine. --set-default, so a TZDIR the user set still wins.
Build the client with Nix, not just a shell for it   364            postFixup = ''
            wrapProgram "$out/bin/jolt" \
Stop carrying the 32-bit GL stack and half of git   366                --prefix PATH : "${pkgs.lib.makeBinPath [ pkgs.gitMinimal pkgs.unzip ]}" \
Build the client with Nix, not just a shell for it   367                --set-default JOLT_OPENSSL_LIBDIR "${pkgs.lib.makeLibraryPath [ pkgs.openssl ]}" \
Read the clock in the reader's zone when /etc/localtime is a file   368                --set-default TZDIR "${pkgs.tzdata}/share/zoneinfo" \
Build the client with Nix, not just a shell for it   369                --set-default SSL_CERT_FILE "${pkgs.cacert}/etc/ssl/certs/ca-bundle.crt"
Build the APK from the flake, and from nothing   373          joltRuntime = joltFrom jolt-src;
Split the tree three ways, and let the phone be Flutter's   374
        # The backends' Clojure halves, which live inside the jolt-native
        # checkout beside the objects they bind. Their own deps.edn asks for
        # glimmer by git — the top-level override below answers for both.
        glimmerCosmic = "${jolt-native}/glimmer-backends/glimmer-cosmic";
Take the Android objects from jolt-native's CI, always the latest   379          glimmerTui = "${jolt-native}/glimmer-backends/glimmer-tui";
Build the client with Nix, not just a shell for it   380
Run this tree on a native half the builders made   381          runtimeLibs = runtimeLibsFor pkgs;
Build the client with Nix, not just a shell for it   382
        # The project as jolt sees it: source, deps.edn, nothing else.
        frqSource = pkgs.runCommand "frq-source" { } ''
          mkdir -p "$out"
Split the tree three ways, and let the phone be Flutter's   386            cp -r ${self}/common ${self}/src ${self}/deps.edn "$out/"
Build the client with Nix, not just a shell for it   387          '';
        # Jolt resolves deps.edn from the working directory, so the launcher
        # runs from the store copy. Its .jolt/cpcache write lands on a
        # read-only directory and jolt treats that as a quiet cache miss, so
        # the only cost is re-resolving the (already local) graph per start.
        frqScript = pkgs.writeShellScript "frq" ''
Bind libmoq_ffi from the object's own metadata, not from its header   394            export LD_LIBRARY_PATH="${nativeAll}/lib:${lib.makeLibraryPath runtimeLibs}''${LD_LIBRARY_PATH:+:$LD_LIBRARY_PATH}"
Let the plane take real devices, not only test thunks   395            export ALSA_PLUGIN_DIR="${alsaPluginDir}"
Build the client with Nix, not just a shell for it   396            cd ${frqSource}
Find the host's GL driver when the store's is not the system's   397
          # On NixOS the store's Mesa is the system's and the window opens.
          # Anywhere else the real driver is the host's, so defer to nixGL —
          # it prepends the host driver, which has to win over ours.
          runner=""
          [ -e /run/current-system ] || runner="${nixGL}/bin/nixGLIntel"
          exec ''${runner} ${joltRuntime}/bin/jolt \
Split the tree three ways, and let the phone be Flutter's   405              -Sdeps '{:deps {jolt-lang/glimmer {:local/root "${glimmer}"} nandi/glimmer-cosmic {:local/root "${glimmerCosmic}"}}}' \
            -m frq.cosmic "$@"
Build the client with Nix, not just a shell for it   407          '';
Paint the same screens into a terminal   409          # The same source, the other backend. No GL, no nixGL and no X11 —
        # a terminal is the one surface that needs nothing from the host but
        # a terminal, which is the reason this output exists.
        tuiScript = pkgs.writeShellScript "frq-tui" ''
Bind libmoq_ffi from the object's own metadata, not from its header   413            export LD_LIBRARY_PATH="${nativeAll}/lib''${LD_LIBRARY_PATH:+:$LD_LIBRARY_PATH}"
Let the plane take real devices, not only test thunks   414            export ALSA_PLUGIN_DIR="${alsaPluginDir}"
Paint the same screens into a terminal   415            cd ${frqSource}
          exec ${joltRuntime}/bin/jolt \
Split the tree three ways, and let the phone be Flutter's   418              -Sdeps '{:deps {jolt-lang/glimmer {:local/root "${glimmer}"} nandi/glimmer-tui {:local/root "${glimmerTui}"}}}' \
Paint the same screens into a terminal   419              -m frq.tui "$@"
        tui = pkgs.runCommand "frq-tui-0.1.0"
            meta = {
              description = "frq's screens in a terminal";
              mainProgram = "frq-tui";
              platforms = systems;
            mkdir -p "$out/bin"
            ln -s ${tuiScript} "$out/bin/frq-tui"
Build the client with Nix, not just a shell for it   435          frq = pkgs.runCommand "frq-0.1.0"
            meta = {
              description = "A freeq client in jolt";
              mainProgram = "frq";
              platforms = systems;
            mkdir -p "$out/bin"
            ln -s ${frqScript} "$out/bin/frq"
Bind the C libraries a call actually needs   449          inherit native moqFfi frqH264 nativeAll frq;
Let the plane take real devices, not only test thunks   450          inherit (pkgs) pipewire;
Merge origin/main, and let one jolt-native answer for both backends   451          inherit tui;
Build the client with Nix, not just a shell for it   452          jolt = joltRuntime;
        default = frq;
Bundle the closure into one file the AppImage runtime mounts   454
Build the APK from the flake, at the rev flake.lock pins   455          # The Android SDK `just apk` copies into flutter/.home. A package
        # rather than something the recipe evaluates inline, so that
        # `nix build .#android-sdk` is how you pre-warm it and `nix flake
        # show` admits it exists.
        android-sdk = androidSdkFor pkgs.stdenv.hostPlatform.system;
Bundle the closure into one file the AppImage runtime mounts   461          # frq and everything it loads, squashed into one runnable file for
        # hosts without Nix. The whole closure rides along — Mesa included,
        # which is not waste: off NixOS the launcher goes through nixGL, and
        # nixGL needs a store Mesa to put the host's driver in front of.
        appimage =
          nix-appimage.bundlers.${pkgs.stdenv.hostPlatform.system}.default frq;
Build the Flutter desktop GUI with nix, sandbox and all   467
Four builds, four hashes, and the one file that was doing it   468          # The other desktop GUI, squashed the same way. `flutter-desktop` is
        # already the nixGL-wrapped launcher rather than the raw Flutter
        # bundle, so this carries the same store Mesa for the same reason —
        # and it is the whole point here, since a host with Flutter's
        # runtime deps but no Nix is exactly who wants one file.
        # Named by its backend, the way the outputs it wraps are: `appimage`
        # is libcosmic's and this is Flutter's, and neither is the default.
        flutter-appimage =
          nix-appimage.bundlers.${pkgs.stdenv.hostPlatform.system}.default
            self.packages.${pkgs.stdenv.hostPlatform.system}.flutter-desktop;
Build the Flutter desktop GUI with nix, sandbox and all   480          # Everything `clojure -M:cljd compile` would otherwise reach the
        # network for, fetched once and hashed.
        # The compile needs three caches, and the reason this is one
        # derivation rather than three is that only one of them is obvious.
        # Maven and gitlibs are the ordinary tools.deps pair. The third is
        # ClojureDart's own: `ensure-cljd-analyzer!` writes a *second*, whole
        # pub project to `.clojuredart/cache/<cljd sha>/cljd_helper`, runs
        # `pub add analyzer` in it, and then runs `bin/analyzer.dart` out of
        # it for the duration of the compile — so a sandbox needs that
        # project already resolved, not just the app's dependencies.
        # Fixed-output, so it is allowed the network the rest of the build is
        # not. What that costs is a hash to maintain, and the thing worth
        # being exact about is *when*: this derivation never sees frq's
        # source. It compiles a three-line throwaway project against the same
        # `flutter/deps.edn` and the same `flutter/pubspec.yaml`, so the hash
        # moves when a dependency moves and not when a screen changes. A
        # stub, rather than `-P` and a hand-built analyzer dir, because
        # running the real compiler once is the only way to be sure the
        # caches are the ones it actually wants.
        # PUB_CACHE lands in $out on purpose. The package_config.json inside
        # cljd_helper carries absolute paths to whatever resolved it, so
        # resolving into a build directory would bake in paths that stop
        # existing the moment this derivation finishes. Pointed at $out they
        # are store paths, and still true.
        cljd-deps =
            flutterPkg = pkgs.flutter;
          pkgs.stdenvNoCC.mkDerivation {
            name = "frq-cljd-deps";
            dontUnpack = true;
            nativeBuildInputs = [
              pkgs.clojure
              pkgs.jdk17
              flutterPkg
              pkgs.git
              pkgs.cacert
            buildCommand = ''
              export HOME="$NIX_BUILD_TOP/home"
              # Resolved in the build directory and copied to $out at the
              # end, never written there directly. A fixed-output derivation
              # may not reference a store path and its own output is a store
              # path, so pub writing its cache's absolute location into its
              # own metadata is enough to fail the check.
              cache="$NIX_BUILD_TOP/cache"
              export PUB_CACHE="$cache/pub-cache"
              export GITLIBS="$cache/gitlibs"
              export SSL_CERT_FILE="${pkgs.cacert}/etc/ssl/certs/ca-bundle.crt"
              mkdir -p "$HOME" "$PUB_CACHE" "$GITLIBS" "$cache/m2"
Make ../common a dependency rather than a path   536                # The stub: our dependency files, nothing of our source.
              # ../common is a :local/root dependency now, so it has to exist
              # *and* carry a deps.edn for tools.deps to resolve — an empty
              # directory with that one file in it is enough.
Build the Flutter desktop GUI with nix, sandbox and all   540                proj="$NIX_BUILD_TOP/stub"
              mkdir -p "$proj/src/stub" "$NIX_BUILD_TOP/common"
Make ../common a dependency rather than a path   542                cp ${./common/deps.edn} "$NIX_BUILD_TOP/common/deps.edn"
Build the Flutter desktop GUI with nix, sandbox and all   543                cp ${./flutter/deps.edn} "$proj/deps.edn"
              cp ${./flutter/pubspec.yaml} "$proj/pubspec.yaml"
Four builds, four hashes, and the one file that was doing it   545                # The lock, or `pub get` resolves against pub.dev and takes
              # whatever satisfies the ranges today. Every build then fetches
              # a slightly different set and the fixed-output hash is a
              # promise nothing can keep.
              cp ${./flutter/pubspec.lock} "$proj/pubspec.lock"
              chmod u+w "$proj/deps.edn" "$proj/pubspec.yaml" "$proj/pubspec.lock"
Build the Flutter desktop GUI with nix, sandbox and all   551                cat > "$proj/src/stub/main.cljd" <<'EOF'
              (ns stub.main)
              (defn main [] nil)
              cd "$proj"
              # `:main` has to name the stub, or the compiler goes looking for
              # frq.main in a tree that is not here.
              sed -i 's/:main frq\.main/:main stub.main/' deps.edn
              flutter config --no-analytics &>/dev/null || true
              flutter config --enable-linux-desktop >/dev/null || true
              clojure -Sdeps '{:mvn/local-repo "'"$cache"'/m2"}' -M:cljd compile
              # What the compile left behind, and only that. The analyzer
              # project is keyed by the ClojureDart sha, so the directory
              # under cache/ is copied wholesale rather than named here.
              mkdir -p "$out/clojuredart"
              cp -r .clojuredart/cache "$out/clojuredart/cache"
              cp -r "$cache/m2" "$out/m2"
              cp -r "$cache/gitlibs" "$out/gitlibs"
              cp -r "$PUB_CACHE" "$out/pub-cache"
              # A fixed-output derivation may not reference a store path, and
              # a resolved pub project is nothing but store paths:
              # package_config.json names the Flutter SDK and every package
              # in the cache by absolute path. So the analyzer project ships
              # *unresolved* — its pubspec and its analyzer.dart and nothing
              # else — and `flutter pub get --offline` re-resolves it against
              # this cache at build time, where naming the store is allowed.
              find "$out" \( -name '.dart_tool' -o -name '.flutter-plugins' \
                  -o -name '.flutter-plugins-dependencies' \) -prune -exec rm -rf {} +
              find "$out" -name '.packages' -delete
              # A fixed-output hash is a promise that two runs agree, so
              # everything a tool writes *about* a run rather than about a
              # dependency has to go: pub's log carries timestamps, Maven
              # rewrites its resolution metadata on every resolve, and
              # tools.gitlibs keeps bare clones it only needs in order to
              # make a checkout. None of it is read offline.
Four builds, four hashes, and the one file that was doing it   593
              # active_roots is the one that was actually breaking this. Pub
              # records the project directories using the cache, sharded by
              # a hash of the path, and $NIX_BUILD_TOP is different on every
              # run -- so two builds whose hosted/ trees were byte-identical
              # still disagreed, purely over which directory had asked. Four
              # builds gave four hashes until this went.
Build the Flutter desktop GUI with nix, sandbox and all   600                rm -rf "$out/pub-cache/log" "$out/pub-cache/_temp" \
                     "$out/pub-cache/git" "$out/pub-cache/global_packages" \
Four builds, four hashes, and the one file that was doing it   602                       "$out/pub-cache/bin" "$out/pub-cache/active_roots"
Build the Flutter desktop GUI with nix, sandbox and all   603
              # tools.gitlibs keeps a bare clone per URL under _repos/, and a
              # bare clone is packfiles — which two runs of the same fetch do
              # not have to produce byte for byte. It cannot simply be
              # deleted, because `procure` calls `ensure-git-dir` before it
              # looks at anything else and would clone it again, over a
              # network this has and the build that uses it does not.
              # It does not need the objects, though. `procure` finds the sha
              # with `match-exact` against the checkout already in libs/, so
              # the bare repo only has to exist. Emptied and re-initialised,
              # it is a fixed handful of files from the pinned git and the
              # same on every run.
              find "$out/gitlibs/_repos" -name HEAD | while read -r head; do
                repo="$(dirname "$head")"
                rm -rf "$repo"
                git init --bare -q "$repo"
                # The sample hooks are shell scripts, so they carry a
                # `#!/nix/store/.../bash` line — which is exactly the kind of
                # store reference a fixed-output derivation may not hold. An
                # empty bare repo nothing ever runs has no use for them.
                rm -rf "$repo/hooks"
              # pub's version listings, which record when they were fetched.
              # This is the one that actually moved between two runs of this
              # derivation: the package sources under hosted/ were identical
              # and the listings beside them were not. Nothing offline reads
              # them — a resolution that already has every package on disk
              # never asks pub.dev what versions exist.
              find "$out/pub-cache" -name '.cache' -type d -prune -exec rm -rf {} +
              find "$out/m2" \( -name '*.lastUpdated' -o -name '_remote.repositories' \
                  -o -name 'resolver-status.properties' -o -name '*.part' \
                  -o -name 'maven-metadata-*.xml*' \) -delete
              find "$out" \( -name '.DS_Store' -o -name '*.log' -o -name '.git' \) \
                  -prune -exec rm -rf {} +
              find "$out" -type d -empty -delete
              chmod -R u+w "$out"
              # Last, after every cleanup above: anything still naming the
              # store fails the fixed-output check, and the error names one
              # path out of thousands of files. This names the files.
              if refs="$(grep -rlI /nix/store "$out" 2>/dev/null)" && [ -n "$refs" ]; then
                echo "cljd-deps: these still reference the store:" >&2
                echo "$refs" | head -20 >&2
              # If two runs disagree, this says which half to look in. Cheap,
              # and the alternative is a hash mismatch with nothing attached.
              for d in "$out"/*; do
                echo "cljd-deps subtree $(basename "$d") $( (cd "$d" && find . -type f \
                    -exec sha256sum {} + | sort -k2 | sha256sum) )" >&2
              for d in "$out"/pub-cache/*/*; do
                [ -d "$d" ] || continue
Four builds, four hashes, and the one file that was doing it   657                  # The path relative to $out, not the basename: two runs that
                # disagree here disagree about *which* directory exists, and
                # a bare `09` names nothing you can go and look at.
                echo "cljd-deps pub ''${d#$out/} $( (cd "$d" && find . -type f \
Build the Flutter desktop GUI with nix, sandbox and all   661                      -exec sha256sum {} + | sort -k2 | sha256sum) )" >&2
            outputHashMode = "recursive";
            outputHashAlgo = "sha256";
            # Moves when flutter/deps.edn or flutter/pubspec.yaml move, and
            # not when frq's own source does — see the stub above.
Four builds, four hashes, and the one file that was doing it   669              outputHash = "sha256-qSGx7WFdVyV7yu4R+EjiQHZcLqwDjYSlohiZcXB43DY=";
Build the Flutter desktop GUI with nix, sandbox and all   670
        # The Flutter desktop GUI, built rather than run out of the tree.
        # `just flutter-desktop` is the working-tree loop and this is its
Name the libcosmic recipe for its backend: `just cosmic run`   675          # opposite number, the same way `nix build .#frq` is `just cosmic
        # run`'s: the source is the flake's, the output is a store path, and the build is
Build the Flutter desktop GUI with nix, sandbox and all   677          # a sandbox with no network. It is the first thing here that builds
        # purely — the APK cannot, because Gradle fetches as it goes.
        # Two stages, because the Dart does not exist until ClojureDart writes
        # it. `preBuild` runs the compiler over `flutter/src` and `common/`
        # with `--offline`, out of the caches `cljd-deps` fetched; everything
        # after that is an ordinary Flutter application as far as nixpkgs is
        # concerned.
        # The caches are copied in rather than used where they lie. Maven,
        # tools.gitlibs and pub all expect to be able to write to their own
        # cache — a lock file, a resolved marker — and the store is read-only,
        # so pointing them at $out of a fixed-output derivation fails in three
        # different ways at three different depths.
        # `src` is the whole tree and not `flutter/`: `flutter/deps.edn` puts
        # `../common` on the classpath, which is the entire point of that
        # directory, and a source root of `flutter/` would leave the screens
        # outside it.
        flutter-desktop-unwrapped = pkgs.flutter.buildFlutterApplication rec {
          pname = "frq-flutter";
          version = "0.1.0";
          src = lib.cleanSourceWith {
            src = ./.;
            # Build trees and caches, which are large, machine-specific and
            # would make every one of them a new store path.
            filter = path: type:
              let base = baseNameOf path; in
              !(builtins.elem base [
                "build" ".home" ".clojuredart" ".cpcache" "cljd-out"
                ".dart_tool" "result" ".git" ".jolt" "buck-out"
          sourceRoot = "source/flutter";
          # Read at eval time, so the lock in git is the lock that is built.
          autoPubspecLock = ./flutter/pubspec.lock;
          # git, because tools.deps resolves the ClojureDart dependency through
          # tools.gitlibs even when every byte of it is already on disk — see
          # the _repos note in cljd-deps.
          nativeBuildInputs = [ pkgs.clojure pkgs.jdk17 pkgs.git ];
          preBuild = ''
            export PUB_CACHE="$NIX_BUILD_TOP/pub-cache"
            export GITLIBS="$NIX_BUILD_TOP/gitlibs"
            cp -r ${self.packages.${pkgs.stdenv.hostPlatform.system}.cljd-deps}/pub-cache "$PUB_CACHE"
            cp -r ${self.packages.${pkgs.stdenv.hostPlatform.system}.cljd-deps}/gitlibs "$GITLIBS"
            cp -r ${self.packages.${pkgs.stdenv.hostPlatform.system}.cljd-deps}/m2 "$NIX_BUILD_TOP/m2"
            mkdir -p .clojuredart
            cp -r ${self.packages.${pkgs.stdenv.hostPlatform.system}.cljd-deps}/clojuredart/cache .clojuredart/cache
            chmod -R u+w "$PUB_CACHE" "$GITLIBS" "$NIX_BUILD_TOP/m2" .clojuredart
            # Resolve the analyzer project here rather than in cljd-deps,
            # which was not allowed to name the store. Offline, out of the
            # cache that derivation did fetch. ClojureDart only reaches for
            # the network when `bin/analyzer.dart` is missing, and it is not.
            for helper in .clojuredart/cache/*/cljd_helper; do
              ( cd "$helper" && flutter pub get --offline )
            # --offline is what keeps `pub get` out of a sandbox that has no
            # network; the analyzer project it would otherwise resolve is
            # already in .clojuredart, put there by cljd-deps.
            clojure -Sdeps "{:mvn/local-repo \"$NIX_BUILD_TOP/m2\"}" \
                -M:cljd compile --offline
          meta = {
            description = "frq's screens on Flutter's Linux target (no GL launcher)";
            mainProgram = "frq";
            platforms = systems;
        # The same shape as `frq` above: a launcher, and a package that is a
        # symlink to it. The reason is the same one `frqScript` gives — on
        # NixOS the store's Mesa is the system's and the window opens, and
        # anywhere else the real driver is the host's, so the process is
        # handed to nixGL. Without it the store build dies on a distrobox
        # Arch with "No provider of eglGetPlatformDisplayEXT found", which is
        # that failure wearing an EGL hat.
        # A wrapper *around* the built application rather than a `postFixup`
        # inside it, because buildFlutterApplication's own dartFixupHook runs
        # after postFixup and rewrites `bin/frq` — so anything done to that
        # path from inside is undone on the way out.
        flutter-desktop =
            unwrapped =
              self.packages.${pkgs.stdenv.hostPlatform.system}.flutter-desktop-unwrapped;
            script = pkgs.writeShellScript "frq" ''
              runner=""
              [ -e /run/current-system ] || runner="${nixGLFor pkgs}/bin/nixGLIntel"
              exec ''${runner} ${unwrapped}/bin/frq "$@"
          pkgs.runCommand "frq-flutter-0.1.0"
              meta = {
                description = "frq's screens on Flutter's Linux target";
                mainProgram = "frq";
                platforms = systems;
              mkdir -p "$out/bin"
              ln -s ${script} "$out/bin/frq"
Build the client with Nix, not just a shell for it   787        });
Name the libcosmic recipe for its backend: `just cosmic run`   789      # Where `just cosmic run` runs, and — because entering it realises what it
Run this tree on a native half the builders made   790      # names — what builds the half of frq that is not this working tree.
    # The two halves, and the split is the whole point of the shell. The frq
    # source is the files on disk, uncommitted edits and all. Everything
    # under it — jolt, glimmer, glimmer-vidya, both native objects — is the
    # flake's, at the revs flake.lock names, so a run says what it ran
    # against and both halves of glimmer-vidya move together. That is the
    # drift the `jolt-native` input's comment is about, and a pin frq can
    # answer for is worth more here than the convenience of a checkout.
Take the native objects from their own flake rather than rebuilding them   800      # `native` is jolt-native's own flake output. It was a buck2 graph when
    # this comment was first written and a cargo build restated here when it
    # was second: buck2 fetches its rustc, zig and every third-party crate as
    # it goes and writes buck-out into the tree it builds, so a sandbox with
    # no network and a read-only store was the one place it could not run.
    # Upstream builds with nix now, so the thing its CI runs and the thing
    # this shell hands a builder are the same derivation.
Run this tree on a native half the builders made   807
    # Nothing here says "nixbuild", though: it is a plain derivation, and
Name the libcosmic recipe for its backend: `just cosmic run`   809      # where it gets built is the machine's business. The `cosmic` recipe asks for
Run this tree on a native half the builders made   810      # the shell with --max-jobs 0, which is what sends it to the `builders`
    # entry rather than compiling egui on a laptop.
    devShells = forEachSystem (pkgs:
      let
        inherit (pkgs) lib;
Bind libmoq_ffi from the object's own metadata, not from its header   815          inherit (self.packages.${pkgs.stdenv.hostPlatform.system}) jolt native nativeAll;
Run this tree on a native half the builders made   816
        default = pkgs.mkShellNoCC {
          name = "frq";
          # jolt, because the runtime frq is run by should be the flake's
          # too. nixGL for the same reason the launcher reaches for it — see
Inline the babashka scripts into the justfile   823            # frqScript. just so the recipe runner comes from here too rather
Name the libcosmic recipe for its backend: `just cosmic run`   824            # than the host — `nix develop` and then `just cosmic run` is the
          # whole of what a machine with nix needs.
Inline the babashka scripts into the justfile   826            packages = [ jolt pkgs.just (nixGLFor pkgs) ];
          # Read by the recipes rather than baked into a wrapper: the frq
Name the libcosmic recipe for its backend: `just cosmic run`   829            # source `just cosmic run` runs is the working tree, so the
          # launcher has to live in that tree and the shell has to hand it its answers.
Inline the babashka scripts into the justfile   831            # Naming these is also what makes the shell build them.
Bind libmoq_ffi from the object's own metadata, not from its header   832            JOLT_NATIVE_LIB = "${nativeAll}/lib";
Let the plane take real devices, not only test thunks   833            # Spelled out rather than shared with the packages block, which
          # is a different `let`. See `alsaPluginDir` there for why.
          ALSA_PLUGIN_DIR = "${pkgs.pipewire}/lib/alsa-lib";
Run this tree on a native half the builders made   836            GLIMMER_SRC = glimmer;
Split the tree three ways, and let the phone be Flutter's   837            GLIMMER_COSMIC_SRC = "${jolt-native}/glimmer-backends/glimmer-cosmic";
Take the Android objects from jolt-native's CI, always the latest   838            GLIMMER_TUI_SRC = "${jolt-native}/glimmer-backends/glimmer-tui";
Run this tree on a native half the builders made   839            FRQ_LIB_PATH = lib.makeLibraryPath (runtimeLibsFor pkgs);
          NIXGL = "${nixGLFor pkgs}/bin/nixGLIntel";
Take the jolt-native beside this one when there is one   841
Take the jolt-native you name, not the one next door   842            # A checkout of jolt-native in place of the pin, when one is NAMED.
Take the jolt-native beside this one when there is one   843
Take the jolt-native you name, not the one next door   844            # The pin is a rev on a server, so the loop for a change to a
          # backend would be commit, push, re-pin, re-lock — four steps and
          # an upload for a line of Rust. Pointing FRQ_JOLT_NATIVE at a
          # working copy makes the loop `cargo build` and `just tui`.
Take the jolt-native beside this one when there is one   848
Take the jolt-native you name, not the one next door   849            # This used to find that copy by itself — ../jolt-native beside the
          # checkout — and that is gone, because a found tree is the wrong
          # default twice over. It fired on a sibling nobody had asked about,
          # so a shell could be running something other than the pin on the
          # strength of a directory existing. And what it prepended was a raw
          # `cargo build` artifact: no store RUNPATH, so its libc.so.6
          # resolves to the host's, and the Nix-glibc jolt that dlopens it
          # gets a second libc and fails. jolt reports that as "required
          # native library ... not found", which names neither libc nor the
          # tree the object came from. An override worth having is one you
          # can see in the command you typed.
Take the jolt-native beside this one when there is one   860
Take the jolt-native you name, not the one next door   861            # So: named or nothing. A named tree is taken even unbuilt (with a
          # word about what to run) — naming it is asking for it — and it has
          # to carry the RUNPATH the store copy does, which in practice means
          # building it under Nix.
Take the jolt-native beside this one when there is one   865
Take the jolt-native you name, not the one next door   866            # Only the sources and the objects a checkout actually builds move.
          # Everything else on the library path — libopus, libmoq_ffi, the
          # ALSA plugins — stays the pin's, since a checkout has no build of
          # those to offer.
Take the jolt-native beside this one when there is one   870            shellHook = ''
Take the jolt-native you name, not the one next door   871              if [ -n "''${FRQ_JOLT_NATIVE:-}" ]; then
Take the jolt-native beside this one when there is one   872                if [ -d "$FRQ_JOLT_NATIVE/crates/jolt-tui" ]; then
                FRQ_JOLT_NATIVE="$(cd "$FRQ_JOLT_NATIVE" && pwd)"
                export FRQ_JOLT_NATIVE
                export GLIMMER_TUI_SRC="$FRQ_JOLT_NATIVE/glimmer-backends/glimmer-tui"
Split the tree three ways, and let the phone be Flutter's   876                  export GLIMMER_COSMIC_SRC="$FRQ_JOLT_NATIVE/glimmer-backends/glimmer-cosmic"
Take the jolt-native beside this one when there is one   877                  # First, so a cargo build wins over the pin's copy of the
                # same object. The rest of the pin's lib directory is still
                # behind it.
                export JOLT_NATIVE_LIB="$FRQ_JOLT_NATIVE/target/release:$JOLT_NATIVE_LIB"
Take the jolt-native you name, not the one next door   881                  echo "frq: jolt-native from $FRQ_JOLT_NATIVE, not the pin (unset FRQ_JOLT_NATIVE for the pin)" >&2
Take the jolt-native beside this one when there is one   882                  if [ ! -e "$FRQ_JOLT_NATIVE/target/release/libjolttui.so" ]; then
                  echo "frq: no libjolttui.so there yet — cargo build --release --features terminal -p jolt-tui" >&2
Take the jolt-native you name, not the one next door   885
Take the jolt-native beside this one when there is one   886                  echo "frq: FRQ_JOLT_NATIVE=$FRQ_JOLT_NATIVE is not a jolt-native checkout; using the pin" >&2
Run this tree on a native half the builders made   890
Build the APK from the flake, at the rev flake.lock pins   891
        # The APK toolchain, which the default shell deliberately does not
        # carry: Flutter brings its own Dart, Gradle and a JDK's worth of
        # closure, and a desktop build has no use for any of it.
        # `just apk` used to name these as `nix shell nixpkgs#clojure
        # nixpkgs#jdk17 nixpkgs#flutter`, which is the flake registry's
        # nixpkgs and not this flake's — so the Flutter under the APK
        # floated while everything else was locked. Same three packages,
        # from flake.lock now.
        # JDK 17 and not newer on purpose: the Flutter template's Gradle
        # plugin pins a Gradle that rejects a JDK it was released before,
        # and the failure reads as an unsupported class file version rather
        # than as a version mismatch.
        flutter = pkgs.mkShellNoCC {
          name = "frq-flutter";
Seed the ClojureDart caches out of the flake   908
          # git, because tools.deps resolves the ClojureDart dependency
          # through tools.gitlibs even when every byte of it is already in
          # the seeded cache — the same reason flutter-desktop-unwrapped
          # names it. The host's git has always been there to answer; naming
          # it means the shell does not depend on that.
          packages = [ pkgs.clojure pkgs.jdk17 pkgs.flutter pkgs.just pkgs.git ];
Build the APK from the flake, at the rev flake.lock pins   915
          # Where the recipe copies from. Naming it here is also what makes
          # entering the shell build it, so the first `just apk` does not
          # stop for a few hundred megabytes of SDK with nothing said about
          # why.
          FRQ_ANDROID_SDK =
            "${androidSdkFor pkgs.stdenv.hostPlatform.system}/libexec/android-sdk";
Seed the ClojureDart caches out of the flake   922
          # The Maven, gitlibs and pub caches the ClojureDart compile would
          # otherwise fetch, plus the analyzer project it writes under
          # .clojuredart. Here for both of FRQ_ANDROID_SDK's reasons: it is
          # where the recipe copies from, and naming it is what makes
          # entering the shell build it.
          # The compile still runs online. These are a warm start and not a
          # pin — `--offline` would be, and would turn adding a line to
          # flutter/deps.edn into a re-hash of cljd-deps before anything
          # compiled again. The sandbox build takes that trade because it
          # has no network; the loop someone edits in should not.
          FRQ_CLJD_DEPS = "${self.packages.${pkgs.stdenv.hostPlatform.system}.cljd-deps}";
Build the APK from the flake, at the rev flake.lock pins   935
Paint the desktop with Flutter too, beside libcosmic   936
        # The other desktop GUI. Same ClojureDart half as the APK — one
        # `clojure -M:cljd compile`, one flutter/src — over Flutter's Linux
        # target instead of its Android one, so `flutter/linux/` is the
        # runner and CMake and Ninja are the build rather than Gradle.
        # A separate shell from `flutter` rather than one that carries both,
        # because the halves are disjoint: this wants GTK and a C++ toolchain
        # and no JDK, and the APK wants a JDK and an SDK and no GTK. Sharing
        # them would mean every desktop build paying for a few hundred
        # megabytes of Android SDK it never opens, which is the same argument
        # that keeps Flutter out of the default shell.
        # mkShell and not mkShellNoCC, unlike every other shell here: this is
        # the one that actually compiles C++. stdenv brings the compiler, and
        # gtk3 in buildInputs is what puts its .pc file where the runner's
        # `pkg_check_modules(GTK gtk+-3.0)` can find it.
        flutter-desktop = pkgs.mkShell {
          name = "frq-flutter-desktop";
          # clojure and flutter are the APK shell's, and deliberately the
          # same two: the Dart that runs here is generated by the same
          # compiler from the same source, and a second Flutter version
          # under it would be a second set of engine artifacts and a second
          # answer to "does the phone build match the desktop one".
          nativeBuildInputs = [
            pkgs.clojure
            pkgs.flutter
            pkgs.just
            pkgs.cmake
            pkgs.ninja
            pkgs.pkg-config
          # gtk3 is the runner's own dependency; the rest are url_launcher's
          # Linux implementation, which is a GTK plugin compiled into the
          # bundle. path_provider needs nothing here — its Linux half is
          # pure Dart over the XDG directories.
          buildInputs = [ pkgs.gtk3 pkgs.glib ];
Name the libcosmic recipe for its backend: `just cosmic run`   976            # Same reason `just cosmic run` reaches for it: Flutter paints
          # through GL, and off NixOS the driver that can do that is the
          # host's, not the store's. The recipe reads this exactly as
          # `cosmic` does.
Paint the desktop with Flutter too, beside libcosmic   980            NIXGL = "${nixGLFor pkgs}/bin/nixGLIntel";
Seed the ClojureDart caches out of the flake   982            # The `flutter` shell's, deliberately the same one and for the
          # same reason clojure and flutter are: the ClojureDart half of
          # both builds is one compile over one deps.edn, so a second set of
          # caches would be a second answer to what it resolved against.
          # This recipe reads the variable directly — it is inside this
          # shell before it does any of the work — where `just apk` reaches
          # for the flake output itself.
          FRQ_CLJD_DEPS = "${self.packages.${pkgs.stdenv.hostPlatform.system}.cljd-deps}";
Paint the desktop with Flutter too, beside libcosmic   991            # The recipe's re-entry test, the way JOLT_NATIVE_LIB is the
          # default shell's. Nothing else sets it, so `just flutter-desktop`
          # outside the shell re-enters and lands back on the same recipe —
          # no flag to forget, and no second code path for someone who runs
          # `nix develop .#flutter-desktop --command just flutter-desktop`
          # by hand.
          FRQ_FLUTTER_DESKTOP = "1";
Run this tree on a native half the builders made   999        });
Build the client with Nix, not just a shell for it   1001      apps = forEachSystem (pkgs: {
      default = {
        type = "app";
        program = "${self.packages.${pkgs.stdenv.hostPlatform.system}.frq}/bin/frq";
Paint the same screens into a terminal   1006        tui = {
        type = "app";
        program = "${self.packages.${pkgs.stdenv.hostPlatform.system}.tui}/bin/frq-tui";
Build the client with Nix, not just a shell for it   1010