Merge pull request #15 from nix-community/gc

fix persistent derivation link

.github/workflows/test.yml

@@ -8,5 +8,9 @@ jobs:
     steps:
     - uses: actions/checkout@v2
     - uses: cachix/install-nix-action@v7
+    - name: Prevent garbage collections of gcroots
+      run:
+        printf "keep-outputs = true\nkeep-derivations = true\n" | sudo tee -a /etc/nix/nix.conf;
+        sudo systemctl restart nix-daemon
     - run:
         nix-shell -I nixpkgs=https://github.com/NixOS/nixpkgs-channels/archive/nixpkgs-unstable.tar.gz ci.nix --run 'true'

direnvrc

@@ -84,7 +84,7 @@ use_nix() {
     local escaped_pwd=${stripped_pwd//-/--}
     local escaped_pwd=${escaped_pwd//\//-}
     ln -fs "$drv" "$drv_link"
-    ln -fs "$PWD/$drv_link" "/nix/var/nix/gcroots/per-user/$LOGNAME/$escaped_pwd"
+    ln -fs "$drv_link" "/nix/var/nix/gcroots/per-user/$USER/$escaped_pwd"
     log_status renewed cache and derivation link
   fi
 

tests/test.py

@@ -2,15 +2,22 @@
 
 from tempfile import TemporaryDirectory
 import os
+import sys
 import subprocess
 from pathlib import Path
 import shutil
 import unittest
+from typing import List
 
 
 TEST_ROOT = Path(__file__).resolve().parent
 
 
+def run(cmd: List[str], **kwargs) -> subprocess.CompletedProcess:
+    print("$ " + " ".join(cmd))
+    return subprocess.run(cmd, **kwargs)
+
+
 class IntegrationTest(unittest.TestCase):
     def setUp(self) -> None:
         self.env = os.environ.copy()
@@ -24,12 +31,32 @@ class IntegrationTest(unittest.TestCase):
             f.write(f"use nix")
 
     def test_direnv(self) -> None:
-        subprocess.run(
+        run(["direnv", "allow"], cwd=str(self.testenv), env=self.env, check=True)
-            ["direnv", "allow"], cwd=str(self.testenv), env=self.env, check=True
+
+        run(["nix-collect-garbage"], check=True)
+
+        out1 = run(
+            ["direnv", "exec", str(self.testenv), "hello"],
+            env=self.env,
+            stderr=subprocess.PIPE,
+            text=True,
         )
-        subprocess.run(
+        sys.stderr.write(out1.stderr)
-            ["direnv", "exec", str(self.testenv), "hello"], env=self.env, check=True
+        self.assertIn("renewed cache and derivation link", out1.stderr)
+        self.assertEqual(out1.returncode, 0)
+
+        run(["nix-collect-garbage"], check=True)
+        run(["sh", "-c", "realpath /nix/var/nix/gcroots/per-user/$USER/*"], check=True)
+
+        out2 = run(
+            ["direnv", "exec", str(self.testenv), "hello"],
+            env=self.env,
+            stderr=subprocess.PIPE,
+            text=True,
         )
+        sys.stderr.write(out2.stderr)
+        self.assertIn("using cached derivation", out2.stderr)
+        self.assertEqual(out2.returncode, 0)
 
     def tearDown(self) -> None:
         self.dir.cleanup()