ci.nix: Add 19.09 for Nix 2.3

ci.nix

@@ -1 +0,0 @@
-import ./tests/default.nix { pkgs = import ./nix {}; }

nix/ci.nix

@@ -0,0 +1,14 @@
+let
+  sources = import ./sources.nix;
+  inherit (import ./dimension.nix { lib = import (sources.nixpkgs + "/lib"); })
+    dimension
+  ;
+  in
+  dimension "Nixpkgs" {
+    "nixpkgs-19_03" = sources."nixos-19.03";
+    "nixpkgs-19_09" = sources."nixos-19.09";
+  } (_key: nixpkgs:
+    import ../tests/default.nix { pkgs = import ./default.nix { inherit nixpkgs; }; }
+  )
+
+#import ./tests/default.nix { pkgs = import ./nix {}; }

nix/default.nix

@@ -1,9 +1,9 @@
-{ sources ? import ./sources.nix }:
+{ sources ? import ./sources.nix, nixpkgs ? sources.nixpkgs }:
 let
   config = {};
   overlays = [(super: self: {
     inherit (import sources.niv {}) niv;
   })];
-  pkgs = import sources.nixpkgs { inherit overlays config; };
+  pkgs = import nixpkgs { inherit overlays config; };
 in
   pkgs

nix/dimension.nix

@@ -0,0 +1,115 @@
+{ lib }:
+{
+  /*
+    dimension: name -> attrs -> function -> attrs
+    where
+      function: keyText -> value -> attrsOf package
+
+    WARNING: Attribute names must not contain periods ("."). 
+             See https://github.com/NixOS/nix/issues/3088
+
+    NOTE: The dimension name will be picked up by agent and web ui soon.
+
+    Specifies a dimension of the build matrix. For example
+
+        dimension "Example" {
+          withP = { p = true; }
+          withoutP = { p = false; }
+        } (key:      # either "withP" or "withoutP"
+          { p }:     # either p = true or p = false
+          myProject p
+        )
+
+    evaluates roughly to
+
+        { 
+          withP = myProject true;
+          withoutP = myProject false;
+        }
+
+    Use nested calls for multiple dimensions.
+    
+    Example:
+
+        dimension "System" {
+          "x86_64-linux" = {};
+          # ...
+          }: (system: {}:
+
+          dimension "Nixpkgs release" (
+            {
+              "nixpkgs-19_03".nixpkgs = someSource
+            } // optionalAttrs (system != "...") {
+              "nixpkgs-unstable".nixpkgs = someOtherSource
+            }
+            ) (_key: { nixpkgs }:
+            
+            myProject system nixpkgs
+
+          )
+        )
+
+    evaluates roughly to
+
+        {
+          x86_64-linux.nixpkgs-19_03 = myProject "x86_64-linux" someSource;
+          x86_64-linux.nixpkgs-unstable = myProject "x86_64-linux" someOtherSource;
+          ...
+        }
+
+    If you need to make references across attributes, you can do so by binding
+    the result. Wherever you write
+
+        dimension "My dimension" {} (key: value: f1 key value)
+
+    You can also write
+
+        let 
+          myDimension = dimension "My dimension" {} (key: value: f2 key value myDimension)
+        in
+          myDimension
+
+    This example builds a single test runner to reuse across releases:
+
+        let
+          overlay =
+            testRunnerPkgs: self: super: {
+              # ...
+            };
+          myProject =
+            { nixpkgs,
+              pkgs ? import nixpkgs { overlays = [ overlay ]; },
+              testRunnerPkgs ? pkgs
+            }: pkgs;
+        in
+
+        let
+          latest = "nixpkgs-19_03";
+          releases =
+            dimension "Nixpkgs release"
+              {
+                nixpkgs-18_09.nixpkgs = someSource
+                nixpkgs-19_03.nixpkgs = someOtherSource
+              }
+              (_key: { nixpkgs }:
+
+                myProject {
+                  inherit nixpkgs;
+                  testRunnerPkgs = releases."${latest}";
+                }
+
+              );
+        in releases;
+
+   */
+  dimension = name: attrs: f:
+    lib.mapAttrs
+      (k: v:
+       let o = f k v;
+       in o // { recurseForDerivations = o.recurseForDerivations or true; }
+      )
+      attrs
+    // { meta.dimension.name = name; };
+    
+  # TODO: move this file somewhere (a flake?)
+}

nix/sources.json

@@ -10,6 +10,30 @@
         "description": "Nixpkgs/NixOS branches that track the Nixpkgs/NixOS channels",
         "rev": "312a059bef8b29b4db4e73dc02ff441cab7bb26d"
     },
+    "nixos-19.03": {
+        "homepage": "https://github.com/NixOS/nixpkgs",
+        "url": "https://github.com/NixOS/nixpkgs-channels/archive/2dfae8e22fde5032419c3027964c406508332974.tar.gz",
+        "owner": "NixOS",
+        "branch": "nixos-19.03",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz",
+        "repo": "nixpkgs-channels",
+        "type": "tarball",
+        "sha256": "0293j9wib78n5nspywrmd9qkvcqq2vcrclrryxqnaxvj3bs1c0vj",
+        "description": "A read-only mirror of NixOS/nixpkgs tracking the released channels. Send issues and PRs to",
+        "rev": "2dfae8e22fde5032419c3027964c406508332974"
+    },
+    "nixos-19.09": {
+        "homepage": "https://github.com/NixOS/nixpkgs",
+        "url": "https://github.com/NixOS/nixpkgs-channels/archive/e6b068cd952e4640d416c2ccd62587d8a35cd774.tar.gz",
+        "owner": "NixOS",
+        "branch": "nixos-19.09",
+        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz",
+        "repo": "nixpkgs-channels",
+        "type": "tarball",
+        "sha256": "1ngac24cmdms1g37cpi6xs666bz1pf0fhw52zxa91i7bj30x9vw5",
+        "description": "A read-only mirror of NixOS/nixpkgs tracking the released channels. Send issues and PRs to",
+        "rev": "e6b068cd952e4640d416c2ccd62587d8a35cd774"
+    },
     "niv": {
         "homepage": "https://github.com/nmattia/niv",
         "url": "https://github.com/nmattia/niv/archive/5d9e3a5f7d51765f0369a4682770ec57d863f19f.tar.gz",