beets: Check plugin definitions against package.

The reason for doing this is in order to not forget about possible
dependencies in new upstream releases, so if upstream is introducing a
new plugin where we're lacking dependencies, the build will fail on our
side and we can check whether we'll need those.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

pkgs/tools/audio/beets/default.nix

@@ -115,6 +115,23 @@ in buildPythonPackage rec {
 
   doCheck = true;
 
+  preCheck = ''
+    (${concatMapStrings (s: "echo \"${s}\";") allPlugins}) \
+      | sort -u > plugins_defined
+    find beetsplug -mindepth 1 \
+      \! -path 'beetsplug/__init__.py' -a \
+      \( -name '*.py' -o -path 'beetsplug/*/__init__.py' \) -print \
+      | sed -n -re 's|^beetsplug/([^/.]+).*|\1|p' \
+      | sort -u > plugins_available
+
+    if ! mismatches="$(diff -y plugins_defined plugins_available)"; then
+      echo "The the list of defined plugins (left side) doesn't match" \
+           "the list of available plugins (right side):" >&2
+      echo "$mismatches" >&2
+      exit 1
+    fi
+  '';
+
   checkPhase = ''
     runHook preCheck