feat(nix): flake-parts, first draft

2026-05-26 20:49:55 +00:00 · 2025-10-27 12:55:20 +00:00
parent cb7875e479
commit 68bea1816f
18 changed files with 757 additions and 1040 deletions
@@ -0,0 +1,77 @@
+{ pkgs, inputs, ... }:
+let
+  inherit (pkgs) lib;
+in
+rec {
+  defaultDisabledFeatures = [
+    # dont include experimental features
+    "experimental"
+    # jemalloc profiling/stats features are expensive and shouldn't
+    # be expected on non-debug builds.
+    "jemalloc_prof"
+    "jemalloc_stats"
+    # this is non-functional on nix for some reason
+    "hardened_malloc"
+    # conduwuit_mods is a development-only hot reload feature
+    "conduwuit_mods"
+    # we don't want to enable this feature set by default but be more specific about it
+    "full"
+  ];
+  # We perform default-feature unification in nix, because some of the dependencies
+  # on the nix side depend on feature values.
+  calcFeatures =
+    {
+      tomlPath ? "${inputs.self}/src/main",
+      # either a list of feature names or a string "all" which enables all non-default features
+      enabledFeatures ? [ ],
+      disabledFeatures ? defaultDisabledFeatures,
+      default_features ? true,
+      disable_release_max_log_level ? false,
+    }:
+    let
+      # simple helper to get the contents of a Cargo.toml file in a nix format
+      getToml = path: lib.importTOML "${path}/Cargo.toml";
+
+      # get all the features except for the default features
+      allFeatures = lib.pipe tomlPath [
+        getToml
+        (manifest: manifest.features)
+        lib.attrNames
+        (lib.remove "default")
+      ];
+
+      # get just the default enabled features
+      allDefaultFeatures = lib.pipe tomlPath [
+        getToml
+        (manifest: manifest.features.default)
+      ];
+
+      # depending on the value of enabledFeatures choose just a set or all non-default features
+      #
+      # - [ list of features ] -> choose exactly the features listed
+      # - "all" -> choose all non-default features
+      additionalFeatures = if enabledFeatures == "all" then allFeatures else enabledFeatures;
+
+      # unification with default features (if enabled)
+      features = lib.unique (additionalFeatures ++ lib.optionals default_features allDefaultFeatures);
+
+      # prepare the features that are subtracted from the set
+      disabledFeatures' =
+        disabledFeatures ++ lib.optionals disable_release_max_log_level [ "release_max_log_level" ];
+
+      # construct the final feature set
+      finalFeatures = lib.subtractLists disabledFeatures' features;
+    in
+    {
+      # final feature set, useful for querying it
+      features = finalFeatures;
+
+      # crane flag with the relevant features
+      cargoExtraArgs = builtins.concatStringsSep " " [
+        "--no-default-features"
+        "--locked"
+        (lib.optionalString (finalFeatures != [ ]) "--features")
+        (builtins.concatStringsSep "," finalFeatures)
+      ];
+    };
+}