Merge pull request #57 from nix-community/fix-macos-ci-2

Author: Mic92

README.md

@@ -134,11 +134,13 @@ $ echo "use nix" >> .envrc
 $ direnv allow
 ```
 
-## Experimental flakes support
+## Flakes support
 
 nix-direnv also comes with a flake alternative. The code is tested and works however
 since future nix versions might change their api regarding this feature we cannot
 guarantee stability after an nix upgrade.
+Likewise `use_nix` the `use_flake` implementation will prevent garbage
+collection of downloaded packages and also for flake inputs.
 
 Save this file as `flake.nix`:
 

direnvrc

@@ -43,18 +43,19 @@ _nix_add_gcroot() {
   local storepath=$1
   local symlink=$2
 
-  local stripped_pwd=${PWD/\//}
+  local stripped_pwd=${2/\//}
   local escaped_pwd=${stripped_pwd//-/--}
   local escaped_pwd=${escaped_pwd//\//-}
-  ln -fs "$storepath" "$symlink"
-  ln -fs "$symlink" "/nix/var/nix/gcroots/per-user/$USER/$escaped_pwd"
+  ln -fsn "$storepath" "$symlink"
+  ln -fsn "$symlink" "/nix/var/nix/gcroots/per-user/$USER/$escaped_pwd"
 }
 
 use_flake() {
   watch_file flake.nix
   watch_file flake.lock
 
   local profile="$(direnv_layout_dir)/flake-profile"
+  local flake="$(direnv_layout_dir)/flake"
   local profile_rc="${profile}.rc"
 
   if [[ ! -e "$profile"
@@ -68,10 +69,20 @@ use_flake() {
     local tmp_profile="$(direnv_layout_dir)/flake-profile.$$"
     [[ -d "$(direnv_layout_dir)" ]] || mkdir -p "$(direnv_layout_dir)"
     local tmp_profile_rc=$(nix print-dev-env --profile "$tmp_profile")
-    drv=$(readlink "$tmp_profile")
+    # macos does not have realpath
+    if command -v realpath >/dev/null; then
+      drv=$(realpath "$tmp_profile")
+    else
+      drv=$(perl -e 'use Cwd "abs_path";print abs_path(shift)' "$tmp_profile")
+    fi
     echo "$tmp_profile_rc" > "$profile_rc"
     rm -f "$tmp_profile" "$tmp_profile"*
     _nix_add_gcroot "$drv" "$profile"
+
+    # also add garbage collection root for source
+    local flake_source=$(nix eval --impure --raw --expr 'builtins.getFlake (toString ./.)')
+    _nix_add_gcroot "$flake_source" "$flake"
+
     log_status renewed cache
   else
     log_status using cached dev shell

tests/test.py

@@ -24,10 +24,10 @@ def support_flakes() -> bool:
         "--json",
         "--eval",
         "--expr",
-        '(builtins.compareVersions "2.4" builtins.nixVersion) == 1',
+        "builtins ? getFlake",
     ]
     proc = subprocess.run(cmd, text=True, capture_output=True, check=True)
-    return proc.stdout != "true"
+    return proc.stdout == "true"
 
 
 class IntegrationTest(unittest.TestCase):
@@ -97,7 +97,10 @@ def test_nix_flake(self) -> None:
             text=True,
         )
         sys.stderr.write(out2.stderr)
+        # check if gcroot symlink has been created and is still valid
+        self.assertTrue(self.testenv.joinpath(".direnv/flake").is_dir())
         self.assertIn("using cached dev shell", out2.stderr)
+
         self.assertEqual(out2.returncode, 0)
 
     def tearDown(self) -> None: