Use custom writeTOML on older nixpkgs

.github/workflows/fast.yml

@@ -10,7 +10,7 @@ jobs:
   linux:
     strategy:
         matrix:
-            nixpkgs: [ nixpkgs, nixpkgs-21.05, nixpkgs-21.11 ]
+            nixpkgs: [ nixpkgs, nixpkgs-21.05, nixpkgs-22.05, nixpkgs-23.05 ]
     runs-on: ubuntu-20.04
     steps:
       - uses: actions/checkout@v2

builtins/default.nix

@@ -8,7 +8,47 @@
 
 rec
 {
-  writeTOML = (formats.toml { }).generate;
+  # Serializes given attrset into a TOML file.
+  #
+  # Usage:
+  #   writeTOML path attrset
+  #
+  # On newer nixpkgs, this function invokes `lib.formats.toml` that nowadays
+  # handles all TOML documents properly.
+  #
+  # On older nixpkgs, where that serializer doesn't work correctly¹, we rely on
+  # a custom implementation (with its own tiny shortcomings²).
+  #
+  # TODO remove our custom serializer after nixpkgs v23 becomes more widely
+  #      adopted
+  #
+  # ¹ e.g. cases like `[targets."cfg(\"something\")"]` are translated badly
+  # ² https://github.com/nix-community/naersk/issues/263
+  writeTOML =
+    let
+      our-impl =
+        let
+          to-toml = import ./to-toml.nix {
+            inherit lib;
+          };
+
+        in
+        name: value:
+          runCommandLocal name {
+            value = to-toml value;
+            passAsFile = [ "value" ];
+          } ''
+            cp "$valuePath" "$out"
+            cat "$out"
+          '';
+
+      nixpkgs-impl = (formats.toml { }).generate;
+
+    in
+    if builtins.compareVersions lib.version "22.11" <= 0 then
+      our-impl
+    else
+      nixpkgs-impl;
 
   readTOML = usePure: f:
     if usePure then

builtins/to-toml.nix

@@ -0,0 +1,139 @@
+{ lib }:
+let
+  inherit (lib)
+    length
+    elemAt
+    concatMap
+    all
+    concatLists
+    concatStringsSep
+    concatMapStringsSep
+    mapAttrsToList
+    ;
+
+  inherit (builtins)
+    abort
+    match
+    toJSON
+    typeOf
+    ;
+
+  quoteKey = k:
+    if match "[a-zA-Z]+" k == []
+    then k
+    else quoteString k;
+
+  quoteString = builtins.toJSON;
+
+  outputValInner = v:
+    let
+      ty = tomlTy v;
+    in
+      if ty == "set" then
+        let
+          vals = mapAttrsToList
+            (k': v': "${quoteKey k'} = ${outputValInner v'}") v;
+          valsStr = concatStringsSep ", " vals;
+        in
+          "{ ${valsStr} }" else
+        outputVal v;
+
+  outputVal = v:
+    let
+      ty = tomlTy v;
+    in
+      if (ty == "bool" || ty == "int") then
+        builtins.toJSON v
+      else
+        if ty == "string" then
+          quoteString v
+        else
+          if ty == "list" || ty == "list_of_attrs" then
+            let
+              vals = map quoteString v;
+              valsStr = concatStringsSep ", " vals;
+            in
+              "[ ${valsStr} ]"
+          else
+            if ty == "set" then
+              abort "unsupported set for not-inner value"
+            else abort "Not implemented: type ${ty}";
+
+  outputKeyValInner = k: v:
+    let
+      ty = tomlTy v;
+    in
+      if ty == "set" then
+        let
+          vals = mapAttrsToList
+            (k': v': "${quoteKey k'} = ${outputValInner v'}") v;
+          valsStr = concatStringsSep ", " vals;
+        in
+          [ "${quoteKey k} = { ${valsStr} }" ] else
+        outputKeyVal k v;
+
+  # Returns a list of strings; one string per line
+  outputKeyVal = k: v:
+    let
+      ty = tomlTy v;
+    in
+      if ty == "bool" || ty == "int" then
+        [ "${quoteKey k} = ${outputValInner v}" ]
+      else
+        if ty == "string" then
+          [ "${quoteKey k} = ${quoteString v}" ]
+        else
+          if ty == "list_of_attrs" then
+            concatMap (
+              inner:
+                [ "[[${k}]]" ] ++ (concatLists (mapAttrsToList outputKeyValInner inner))
+            ) v
+          else
+            if ty == "list" then
+              let
+                vals = map quoteString v;
+                valsStr = concatStringsSep ", " vals;
+              in
+                [ "${quoteKey k} = [ ${valsStr} ]" ] else
+              if ty == "set" then
+                [ "[${k}]" ] ++ (concatLists (mapAttrsToList outputKeyValInner v))
+              else abort "Not implemented: type ${ty} for key ${k}";
+
+  tomlTy = x:
+    if typeOf x == "string" then "string" else
+      if typeOf x == "bool" then "bool" else
+        if typeOf x == "int" then "int" else
+          if typeOf x == "float" then "float" else
+            if typeOf x == "set" then
+              if lib.isDerivation x then "string" else "set" else
+              if typeOf x == "list" then
+                if length x == 0 then "list"
+                else
+                  let
+                    ty = typeOf (elemAt x 0);
+                  in
+                    #assert (all (v: typeOf v == ty) x);
+                    if ty == "set" then "list_of_attrs" else "list"
+              else abort "Not implemented: toml type for ${typeOf x}";
+
+  toTOML = attrs:
+    assert (typeOf attrs == "set");
+    let
+      byTy = lib.foldl
+        (
+          acc: x:
+            let
+              ty = tomlTy x.v;
+            in
+              acc // { "${ty}" = (acc.${ty} or []) ++ [ x ]; }
+        )
+        {} (mapAttrsToList (k: v: { inherit k v; }) attrs);
+    in
+      concatMapStringsSep "\n"
+        (kv: concatStringsSep "\n" (outputKeyVal kv.k kv.v))
+        (
+          (byTy.string or []) ++ (byTy.int or []) ++ (byTy.float or []) ++ (byTy.list or []) ++ (byTy.list_of_attrs or []) ++ (byTy.set or [])
+        )
+  ;
+in
+toTOML

nix/sources.json

@@ -60,15 +60,15 @@
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
     "nixpkgs": {
-        "branch": "master",
+        "branch": "nixpkgs-unstable",
         "description": "Nixpkgs/NixOS branches that track the Nixpkgs/NixOS channels",
         "homepage": null,
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "1df733d83081fe79c109b066c90badece6b8d8b1",
-        "sha256": "1m3s4xv35jilrmbv8hj9gzpbcqgb8vb0iqhzcm1261x8b1hiylvj",
+        "rev": "d2b52322f35597c62abf56de91b0236746b2a03d",
+        "sha256": "1zrqry4m22rbscazxbcqf5ym7ckm6v7pvxpsml23whc1gjf2hkk3",
         "type": "tarball",
-        "url": "https://github.com/NixOS/nixpkgs/archive/1df733d83081fe79c109b066c90badece6b8d8b1.tar.gz",
+        "url": "https://github.com/NixOS/nixpkgs/archive/d2b52322f35597c62abf56de91b0236746b2a03d.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
     "nixpkgs-21.05": {
@@ -83,16 +83,28 @@
         "url": "https://github.com/NixOS/nixpkgs/archive/6d684ea3adef590a2174f2723134e1ea377272d2.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
-    "nixpkgs-21.11": {
-        "branch": "release-21.11",
+    "nixpkgs-22.05": {
+        "branch": "release-22.05",
         "description": "Nix Packages collection",
         "homepage": "",
         "owner": "NixOS",
         "repo": "nixpkgs",
-        "rev": "432864f33c84af53192d4b23ee5871697e57f094",
-        "sha256": "0sqmasma9qin7nhfzv50d1la1mi1yazn7gx2lrxi9j61i9j8l3zm",
+        "rev": "380be19fbd2d9079f677978361792cb25e8a3635",
+        "sha256": "154x9swf494mqwi4z8nbq2f0sp8pwp4fvx51lqzindjfbb9yxxv5",
         "type": "tarball",
-        "url": "https://github.com/NixOS/nixpkgs/archive/432864f33c84af53192d4b23ee5871697e57f094.tar.gz",
+        "url": "https://github.com/NixOS/nixpkgs/archive/380be19fbd2d9079f677978361792cb25e8a3635.tar.gz",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
+    },
+    "nixpkgs-23.05": {
+        "branch": "release-23.05",
+        "description": "Nix Packages collection",
+        "homepage": "",
+        "owner": "NixOS",
+        "repo": "nixpkgs",
+        "rev": "b81af66deb21f73a70c67e5ea189568af53b1e8c",
+        "sha256": "172i5kzn8qja3k0rz9wfj86fgbw2ivc68yw3ra8g86byqc1rcw1m",
+        "type": "tarball",
+        "url": "https://github.com/NixOS/nixpkgs/archive/b81af66deb21f73a70c67e5ea189568af53b1e8c.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
     "nixpkgs-mozilla": {

test/slow/agent-rs/default.nix

@@ -1,5 +1,18 @@
-{ sources, naersk, pkgs, ... }:
+{ sources, pkgs, ... }:
+let
+  fenix = import sources.fenix { };
 
+  toolchain = fenix.fromToolchainFile {
+    file = "${sources.agent-rs}/rust-toolchain.toml";
+    sha256 = "sha256-DzNEaW724O8/B8844tt5AVHmSjSQ3cmzlU4BP90oRlY=";
+  };
+
+  naersk = pkgs.callPackage ../../../default.nix {
+    cargo = toolchain;
+    rustc = toolchain;
+  };
+
+in
 naersk.buildPackage {
   src = sources.agent-rs;
 

test/slow/probe-rs/default.nix

@@ -27,7 +27,14 @@ let
   };
 
 in
-pkgs.runCommand "probe-rs-test"
-{
-  buildInputs = [ app ];
-} "rtthost --help && touch $out"
+if builtins.compareVersions pkgs.lib.version "22.11" <= 0 then
+  # Executing this test requires nixpkgs > 22.11 due to changes to the TOML
+  # serialization function.
+  #
+  # See `writeTOML` in this repository for more details.
+  true
+else
+  pkgs.runCommand "probe-rs-test"
+  {
+    buildInputs = [ app ];
+  } "rtthost --help && touch $out"