Adding documentation to wrap.sh, added ability to retain any desired environment variables.

pkgs/development/python-modules/generic/default.nix

@@ -47,11 +47,24 @@
 # Execute after shell hook
 , postShellHook ? ""
 
+# Environment variables to set in wrapper scripts, in addition to
+# PYTHONPATH and PATH.
+, setEnvVars ? []
+
 , ... } @ attrs:
 
 
 # Keep extra attributes from `attrs`, e.g., `patchPhase', etc.
-if disabled then throw "${name} not supported for interpreter ${python.executable}" else python.stdenv.mkDerivation (attrs // {
+if disabled
+then throw "${name} not supported for interpreter ${python.executable}"
+else
+
+let
+  inherit (builtins) hasAttr;
+  inherit (lib) mapAttrs concatStringsSep optionals hasSuffix;
+in
+
+python.stdenv.mkDerivation (attrs // {
   inherit doCheck;
 
   name = namePrefix + name;

pkgs/development/python-modules/generic/wrap.sh

@@ -41,9 +41,17 @@ wrapPythonProgramsIn() {
                 # wrapProgram creates the executable shell script described
                 # above. The script will set PYTHONPATH and PATH variables.!
                 # (see pkgs/build-support/setup-hooks/make-wrapper.sh)
-                wrapProgram $f \
+                local wrap_args="$f \
                                  --prefix PYTHONPATH ':' $program_PYTHONPATH \
-                              --prefix PATH ':' $program_PATH
+                                 --prefix PATH ':' $program_PATH"
+
+                # Add any additional environment variables to propagate.
+                for env_var in $setEnvVars; do
+                    # Look up the value of this variable
+                    local value=$(eval "echo \$$env_var")
+                    wrap_args="$wrap_args --set $env_var $value"
+                done
+                wrapProgram $wrap_args
             fi
         fi
     done