refactor: use subdirectories directly instead of relying on rootSrc

The problem with rootSrc is that it changes whenever something (that
isn't covered by .gitignore) in the tree changes. This means that after
_any_ change all derivations need to be rebuild. By using the
subdirectories we need as a starting point instead of the filtered root
source, we can avoid this.

4 files changed, 19 insertions, 17 deletions

diff --git a/default.nix b/default.nix
index 33d10a4..be5d524 100644
--- a/default.nix
+++ b/default.nix
@@ -6,11 +6,10 @@ let
 
   version = import ./nix/version.nix;
   root = ./.;
-  sourceName = "flipdot-gschichtler-source";
 
-  rootSrc = builtins.path {
-    path = root;
-    name = sourceName;
+  getSrc = name: builtins.path {
+    name = builtins.baseNameOf name;
+    path = root + "/${name}";
     filter = gi.gitignoreFilter (builtins.readFile ./.gitignore) root;
   };
 
@@ -19,13 +18,13 @@ in
 rec {
   warteraum-static = pkgs.pkgsStatic.callPackage ./nix/warteraum.nix {
     inherit (pkgs.pkgsStatic.llvmPackages) stdenv;
-    inherit rootSrc sourceName;
+    inherit getSrc;
     inherit (python3.pkgs) pytest pytest-randomly requests flipdot-gschichtler;
   };
 
   warteraum = pkgs.callPackage ./nix/warteraum.nix {
     inherit (pkgs.llvmPackages_latest) stdenv;
-    inherit rootSrc sourceName;
+    inherit getSrc;
     inherit (python3.pkgs) pytest pytest-randomly requests flipdot-gschichtler;
   };
 
@@ -33,7 +32,7 @@ rec {
     pname = "bahnhofshalle";
     inherit version;
 
-    src = rootSrc + "/bahnhofshalle";
+    src = getSrc "bahnhofshalle";
 
     nativeBuildInputs = [
       pkgs.buildPackages.esbuild
@@ -53,7 +52,7 @@ rec {
           pname = "anzeigetafel";
           inherit version;
 
-          src = rootSrc + "/anzeigetafel";
+          src = getSrc "anzeigetafel";
 
           propagatedBuildInputs = [ flipdots flipdot-gschichtler ];
 
@@ -73,11 +72,11 @@ rec {
   python3 = pkgs.python3.override {
     packageOverrides = self: super: {
       flipdots = self.callPackage ./nix/python-flipdots.nix {
-        inherit rootSrc;
+        inherit getSrc;
       };
 
       flipdot-gschichtler = self.callPackage ./nix/python-flipdot-gschichtler.nix {
-        inherit rootSrc;
+        inherit getSrc;
       };
     };
   };
diff --git a/nix/python-flipdot-gschichtler.nix b/nix/python-flipdot-gschichtler.nix
index a85598d..630a2ce 100644
--- a/nix/python-flipdot-gschichtler.nix
+++ b/nix/python-flipdot-gschichtler.nix
@@ -1,12 +1,12 @@
 { buildPythonPackage, requests
-, rootSrc
+, getSrc
 }:
 
 buildPythonPackage rec {
   pname = "flipdot-gschichtler";
   version = import ./version.nix;
 
-  src = rootSrc + "/clients/py";
+  src = getSrc "clients/py";
 
   doCheck = false;
 
diff --git a/nix/python-flipdots.nix b/nix/python-flipdots.nix
index 88d1324..6ba0ba3 100644
--- a/nix/python-flipdots.nix
+++ b/nix/python-flipdots.nix
@@ -1,12 +1,12 @@
 { buildPythonPackage, pillow, numpy, flask
-, rootSrc
+, getSrc
 }:
 
 buildPythonPackage {
   name = "flipdots";
   version = "unstable";
 
-  src = rootSrc + "/third_party/flipdots";
+  src = getSrc "third_party/flipdots";
 
   propagatedBuildInputs = [ flask pillow numpy ];
 
diff --git a/nix/warteraum.nix b/nix/warteraum.nix
index af954a7..d1b41ce 100644
--- a/nix/warteraum.nix
+++ b/nix/warteraum.nix
@@ -1,15 +1,18 @@
 { stdenv, lib, scrypt
 , jq, requests, pytest, pytest-randomly, flipdot-gschichtler, valgrind
-, rootSrc, sourceName
+, getSrc
 }:
 
 stdenv.mkDerivation rec {
   pname = "warteraum";
   version = import ./version.nix;
 
-  sourceRoot = sourceName + "/warteraum";
+  src = [
+    (getSrc "warteraum")
+    (getSrc "third_party")
+  ];
 
-  src = rootSrc;
+  sourceRoot = "warteraum";
 
   makeFlags = [
     "PREFIX=${placeholder "out"}"