Merge pull request 'clan_lib flake: fix handling garbage collected store paths as cached values' (#3699) from select-path-fix into main

Reviewed-on: https://git.clan.lol/clan/clan-core/pulls/3699

pkgs/clan-cli/clan_lib/flake/flake.py

@@ -1,5 +1,6 @@
 import json
 import logging
+import os
 from dataclasses import asdict, dataclass, field
 from enum import Enum
 from hashlib import sha1
@@ -318,9 +319,10 @@ class FlakeCacheEntry:
         # strings need to be checked if they are store paths
         # if they are, we store them as a dict with the outPath key
         # this is to mirror nix behavior, where the outPath of an attrset is used if no further key is specified
-        elif isinstance(value, str) and value.startswith("/nix/store/"):
+        elif isinstance(value, str) and value.startswith(
+            os.environ.get("NIX_STORE_DIR", "/nix/store")
+        ):
             assert selectors == []
-            if value.startswith("/nix/store/"):
             self.value = {"outPath": FlakeCacheEntry(value)}
 
         # if we have a normal scalar, we check if it conflicts with a maybe already store value
@@ -337,7 +339,9 @@ class FlakeCacheEntry:
         selector: Selector
 
         # for store paths we have to check if they still exist, otherwise they have to be rebuild and are thus not cached
-        if isinstance(self.value, str) and self.value.startswith("/nix/store/"):
+        if isinstance(self.value, str) and self.value.startswith(
+            os.environ.get("NIX_STORE_DIR", "/nix/store")
+        ):
             return Path(self.value).exists()
 
         # if self.value is not dict but we request more selectors, we assume we are cached and an error will be thrown in the select function
@@ -345,7 +349,8 @@ class FlakeCacheEntry:
             return True
 
         if selectors == []:
-            return self.fetched_all
+            selector = Selector(type=SelectorType.ALL)
+        else:
             selector = selectors[0]
 
         # we just fetch all subkeys, so we need to check of we inserted all keys at this level before
@@ -739,18 +744,36 @@ class Flake:
             )
             select_hash = select_flake.hash
 
+        # fmt: off
         nix_code = f"""
             let
               flake = builtins.getFlake "path:{self.store_path}?narHash={self.hash}";
-              selectLib = (builtins.getFlake "path:{select_source()}?narHash={select_hash}").lib;
+              selectLib = (
-              nixpkgs = flake.inputs.nixpkgs or (builtins.getFlake "path:{nixpkgs_source()}?narHash={fallback_nixpkgs_hash}");
+                builtins.getFlake
+                  "path:{select_source()}?narHash={select_hash}"
+              ).lib;
             in
-              nixpkgs.legacyPackages.{config["system"]}.writeText "clan-flake-select" (
+              derivation {{
-                builtins.toJSON [ {" ".join([f"(selectLib.applySelectors (builtins.fromJSON ''{attr}'') flake)" for attr in str_selectors])} ]
+                name = "clan-flake-select";
-              )
+                system = "{config["system"]}";
+                builder = "/bin/sh";
+                args = [
+                  "-c"
+                  ''
+                    printf %s '${{builtins.toJSON [
+                      {" ".join(
+                          [
+                              f"(selectLib.applySelectors (builtins.fromJSON ''{attr}'') flake)"
+                              for attr in str_selectors
+                          ]
+                      )}
+                    ]}}' > $out
+                  ''
+                ];
+              }}
         """
+        # fmt: on
         if tmp_store := nix_test_store():
-            nix_options += ["--store", str(tmp_store)]
             nix_options.append("--impure")
 
         build_output = Path(

pkgs/clan-cli/clan_lib/flake/flake_test.py

@@ -1,4 +1,8 @@
 import logging
+import subprocess
+from pathlib import Path
+from tempfile import TemporaryDirectory
+from unittest.mock import patch
 
 import pytest
 from clan_cli.tests.fixtures_flakes import ClanFlake
@@ -347,10 +351,6 @@ def test_conditional_all_selector(flake: ClanFlake) -> None:
 # Test that the caching works
 @pytest.mark.with_core
 def test_caching_works(flake: ClanFlake) -> None:
-    from unittest.mock import patch
-
-    from clan_lib.flake import Flake
-
     my_flake = Flake(str(flake.path))
 
     with patch.object(
@@ -363,6 +363,42 @@ def test_caching_works(flake: ClanFlake) -> None:
         assert tracked_build.call_count == 1
 
 
+@pytest.mark.with_core
+def test_cache_gc(monkeypatch: pytest.MonkeyPatch) -> None:
+    with TemporaryDirectory() as tempdir_:
+        tempdir = Path(tempdir_)
+
+        monkeypatch.setenv("NIX_STATE_DIR", str(tempdir / "var"))
+        monkeypatch.setenv("NIX_LOG_DIR", str(tempdir / "var" / "log"))
+        monkeypatch.setenv("NIX_STORE_DIR", str(tempdir / "store"))
+        monkeypatch.setenv("NIX_CACHE_HOME", str(tempdir / "cache"))
+        monkeypatch.setenv("HOME", str(tempdir / "home"))
+        monkeypatch.delenv("CLAN_TEST_STORE")
+        monkeypatch.setenv("NIX_BUILD_TOP", str(tempdir / "build"))
+
+        test_file = tempdir / "flake" / "testfile"
+        test_file.parent.mkdir(parents=True, exist_ok=True)
+        test_file.write_text("test")
+
+        test_flake = tempdir / "flake" / "flake.nix"
+        test_flake.write_text("""
+            {
+              outputs = _: {
+                testfile = ./testfile;
+              };
+            }
+        """)
+
+        my_flake = Flake(str(tempdir / "flake"))
+        my_flake.select(
+            "testfile", nix_options=["--sandbox-build-dir", str(tempdir / "build")]
+        )
+        assert my_flake._cache is not None  # noqa: SLF001
+        assert my_flake._cache.is_cached("testfile")  # noqa: SLF001
+        subprocess.run(["nix-collect-garbage"], check=True)
+        assert not my_flake._cache.is_cached("testfile")  # noqa: SLF001
+
+
 # This test fails because the CI sandbox does not have the required packages to run the generators
 # maybe @DavHau or @Qubasa can fix this at some point :)
 # @pytest.mark.with_core