Nix: Don't depend on subversion.patches being present

default.nix

@@ -1,152 +1,152 b''
 # Nix environment for the community edition
 #
 # This shall be as lean as possible, just producing the rhodecode-vcsserver
 # derivation. For advanced tweaks to pimp up the development environment we use
 # "shell.nix" so that it does not have to clutter this file.
 
 { pkgs ? (import <nixpkgs> {})
 , pythonPackages ? "python27Packages"
 , pythonExternalOverrides ? self: super: {}
 , doCheck ? true
 }:
 
 let pkgs_ = pkgs; in
 
 let
   pkgs = pkgs_.overridePackages (self: super: {
     # Override subversion derivation to
     #  - activate python bindings
     subversion = let
       subversionWithPython = super.subversion.override {
         httpSupport = true;
         pythonBindings = true;
         python = self.python27Packages.python;
       };
     in pkgs.lib.overrideDerivation subversionWithPython (oldAttrs: {
-      patches = oldAttrs.patches ++
+      patches = (oldAttrs.patches or []) ++
         pkgs.lib.optionals pkgs.stdenv.isDarwin [
           # johbo: "import svn.client" fails on darwin currently.
           ./pkgs/subversion-1.9.4-darwin.patch
         ];
     });
   });
 
   inherit (pkgs.lib) fix extends;
 
   basePythonPackages = with builtins; if isAttrs pythonPackages
     then pythonPackages
     else getAttr pythonPackages pkgs;
 
   elem = builtins.elem;
   basename = path: with pkgs.lib; last (splitString "/" path);
   startsWith = prefix: full: let
     actualPrefix = builtins.substring 0 (builtins.stringLength prefix) full;
   in actualPrefix == prefix;
 
   src-filter = path: type: with pkgs.lib;
     let
       ext = last (splitString "." path);
     in
       !elem (basename path) [
         ".git" ".hg" "__pycache__" ".eggs" "node_modules"
         "build" "data" "tmp"] &&
       !elem ext ["egg-info" "pyc"] &&
       !startsWith "result" path;
 
   rhodecode-vcsserver-src = builtins.filterSource src-filter ./.;
 
   pythonGeneratedPackages = self: basePythonPackages.override (a: {
     inherit self;
   })
   // (scopedImport {
     self = self;
     super = basePythonPackages;
     inherit pkgs;
     inherit (pkgs) fetchurl fetchgit;
   } ./pkgs/python-packages.nix);
 
   pythonOverrides = import ./pkgs/python-packages-overrides.nix {
     inherit
       basePythonPackages
       pkgs;
   };
 
   version = builtins.readFile ./vcsserver/VERSION;
 
   pythonLocalOverrides = self: super: {
     rhodecode-vcsserver = super.rhodecode-vcsserver.override (attrs: {
       inherit
         doCheck
         version;
       name = "rhodecode-vcsserver-${version}";
       releaseName = "RhodeCodeVCSServer-${version}";
       src = rhodecode-vcsserver-src;
 
       propagatedBuildInputs = attrs.propagatedBuildInputs ++ ([
         pkgs.git
         pkgs.subversion
       ]);
 
       # TODO: johbo: Make a nicer way to expose the parts. Maybe
       # pkgs/default.nix?
       passthru = {
         pythonPackages = self;
       };
 
       # Somewhat snappier setup of the development environment
       # TODO: move into shell.nix
       # TODO: think of supporting a stable path again, so that multiple shells
       #       can share it.
       shellHook = ''
         # Set locale
         export LC_ALL="en_US.UTF-8"
 
         tmp_path=$(mktemp -d)
         export PATH="$tmp_path/bin:$PATH"
         export PYTHONPATH="$tmp_path/${self.python.sitePackages}:$PYTHONPATH"
         mkdir -p $tmp_path/${self.python.sitePackages}
         python setup.py develop --prefix $tmp_path --allow-hosts ""
       '';
 
       # Add VCSServer bin directory to path so that tests can find 'vcsserver'.
       preCheck = ''
         export PATH="$out/bin:$PATH"
       '';
 
       postInstall = ''
         echo "Writing meta information for rccontrol to nix-support/rccontrol"
         mkdir -p $out/nix-support/rccontrol
         cp -v vcsserver/VERSION $out/nix-support/rccontrol/version
         echo "DONE: Meta information for rccontrol written"
 
         ln -s ${self.pyramid}/bin/* $out/bin  #*/
         ln -s ${self.gunicorn}/bin/gunicorn $out/bin/
 
         # Symlink version control utilities
         #
         # We ensure that always the correct version is available as a symlink.
         # So that users calling them via the profile path will always use the
         # correct version.
         ln -s ${pkgs.git}/bin/git $out/bin
         ln -s ${self.mercurial}/bin/hg $out/bin
         ln -s ${pkgs.subversion}/bin/svn* $out/bin
 
         for file in $out/bin/*; do  #*/
           wrapProgram $file \
             --prefix PYTHONPATH : $PYTHONPATH \
             --set PYTHONHASHSEED random
         done
       '';
 
     });
   };
 
   # Apply all overrides and fix the final package set
   myPythonPackages =
     (fix
     (extends pythonExternalOverrides
     (extends pythonLocalOverrides
     (extends pythonOverrides
              pythonGeneratedPackages))));
 
 in myPythonPackages.rhodecode-vcsserver