Merge pull request #94 from zimbatm/one-nixpkgs-instance

use one nixpkgs instance

flake.nix

@@ -41,7 +41,7 @@
       supportedSystems = [ "x86_64-linux" "x86_64-darwin" "aarch64-darwin" ];
 
       forAllSystems = f: lib.genAttrs supportedSystems (system:
-        f system (import nixpkgs { inherit system; overlays = [ self.overlay ]; })
+        f system nixpkgs.legacyPackages.${system}
       );
 
       # To use dream2nix in non-flake + non-IFD enabled repos, the source code of dream2nix
@@ -113,14 +113,6 @@
 
     in
       {
-        # overlay with flakes enabled nix
-        # (all of dream2nix cli dependends on nix ^2.4)
-        overlay = final: prev: {
-          nix = prev.writeScriptBin "nix" ''
-            ${final.nixUnstable}/bin/nix --option experimental-features "nix-command flakes" "$@"
-          '';
-        };
-
         # System independent dream2nix api.
         # Similar to drem2nixFor but will require 'system(s)' or 'pkgs' as an argument.
         # Produces flake-like output schema.

src/apps/cli/commands/add.py

@@ -12,7 +12,7 @@ import networkx as nx
 from cleo import Command, argument, option
 
 from utils import config, dream2nix_src, checkLockJSON, list_translators_for_source, strip_hashes_from_lock
-from nix_ffi import callNixFunction, buildNixFunction, buildNixAttribute
+from nix_ffi import nix, callNixFunction, buildNixFunction, buildNixAttribute
 
 
 class AddCommand(Command):
@@ -294,12 +294,9 @@ class AddCommand(Command):
     with open(outputDreamLock, 'w') as f:
       json.dump(lock, f, indent=2)
     # compute FOD hash of aggregated sources
-    proc = sp.run(
-      [
-        "nix", "build", "--impure", "-L", "--show-trace", "--expr",
-        f"(import {dream2nix_src} {{}}).fetchSources {{ dreamLock = {outputDreamLock}; }}"
-      ],
-      capture_output=True,
+    proc = nix(
+      "build", "--impure", "-L", "--show-trace", "--expr",
+      f"(import {dream2nix_src} {{}}).fetchSources {{ dreamLock = {outputDreamLock}; }}"
     )
     # read the output hash from the failed build log
     match = re.search(r"FOD_HASH=(.*=)", proc.stderr.decode())

src/apps/cli/nix_ffi.py

@@ -6,6 +6,8 @@ import tempfile
 
 dream2nix_src = os.environ.get("dream2nixSrc")
 
+def nix(*args, **kwargs):
+  return sp.run(["nix", "--option", "experimental-features", "nix-command flakes"] + list(args), capture_output=True, **kwargs)
 
 def callNixFunction(function_path, **kwargs):
   with tempfile.NamedTemporaryFile("w") as input_json_file:
@@ -15,19 +17,16 @@ def callNixFunction(function_path, **kwargs):
     env.update(dict(
       FUNC_ARGS=input_json_file.name
     ))
-    proc = sp.run(
-      [
-        "nix", "eval", "--show-trace", "--impure", "--raw", "--expr",
-        f'''
-          let
-            d2n = (import {dream2nix_src} {{}});
-          in
-            builtins.toJSON (
-              (d2n.utils.callViaEnv d2n.{function_path})
-            )
-        ''',
-      ],
-      capture_output=True,
+    proc = nix(
+      "eval", "--show-trace", "--impure", "--raw", "--expr",
+      f'''
+        let
+          d2n = (import {dream2nix_src} {{}});
+        in
+          builtins.toJSON (
+            (d2n.utils.callViaEnv d2n.{function_path})
+          )
+      ''',
       env=env
     )
   if proc.returncode:
@@ -47,17 +46,14 @@ def buildNixFunction(function_path, **kwargs):
     env.update(dict(
       FUNC_ARGS=input_json_file.name
     ))
-    proc = sp.run(
-      [
-        "nix", "build", "--show-trace", "--impure", "-o", "tmp-result", "--expr",
-        f'''
-          let
-            d2n = (import {dream2nix_src} {{}});
-          in
-            (d2n.utils.callViaEnv d2n.{function_path})
-        ''',
-      ],
-      capture_output=True,
+    proc = nix(
+      "build", "--show-trace", "--impure", "-o", "tmp-result", "--expr",
+      f'''
+        let
+          d2n = (import {dream2nix_src} {{}});
+        in
+          (d2n.utils.callViaEnv d2n.{function_path})
+      ''',
       env=env
     )
   if proc.returncode:
@@ -72,12 +68,9 @@ def buildNixFunction(function_path, **kwargs):
 
 
 def buildNixAttribute(attribute_path):
-  proc = sp.run(
-    [
-      "nix", "build", "--show-trace", "--impure", "-o", "tmp-result", "--expr",
-      f"(import {dream2nix_src} {{}}).{attribute_path}",
-    ],
-    capture_output=True,
+  proc = nix(
+    "build", "--show-trace", "--impure", "-o", "tmp-result", "--expr",
+    f"(import {dream2nix_src} {{}}).{attribute_path}",
   )
   if proc.returncode:
     print(f"Failed to build '{attribute_path}'", file=sys.stderr)

src/default.nix

@@ -7,12 +7,7 @@
   pkgs ? import <nixpkgs> {},
   dlib ? import ./lib { inherit lib; },
   lib ? pkgs.lib,
-
-  # the dream2nix cli depends on some nix 2.4 features
-  nix ? pkgs.writeScriptBin "nix" ''
-    #!${pkgs.bash}/bin/bash
-    ${pkgs.nixUnstable}/bin/nix --option experimental-features "nix-command flakes" "$@"
-  '',
+  nix ? pkgs.nix,
 
   # default to empty dream2nix config
   config ?