Nix >=2.20 breakage fixes (#98)

Author: goodlyrottenapple

src/kup/__main__.py

@@ -249,13 +249,15 @@ def reload_packages(load_versions: bool = True) -> None:
     if os.path.exists(f'{os.getenv("HOME")}/.nix-profile/manifest.json'):
         manifest_file = open(f'{os.getenv("HOME")}/.nix-profile/manifest.json')
         manifest = json.loads(manifest_file.read())['elements']
+        if type(manifest) is list:
+            manifest = dict(enumerate(manifest))
         manifest_file.close()
     else:
-        manifest = []
+        manifest = {}
 
     pinned_package_cache_reverse = {v: k for k, v in pinned_package_cache.items()}
     packages = {}
-    for idx, m in enumerate(manifest):
+    for idx, m in manifest.items():
         # fix potential inconsistencies between nix profiles
         # sometimes storing url/originalUrl and sometimes uri/originalUri
         if 'uri' in m:

src/kup/nix.py

@@ -86,6 +86,23 @@ def nix_raw(
     .replace('"', '')
 )
 
+# based on https://github.com/NixOS/nixpkgs/blob/d329d65edb3680f5aa7cc46b364a564bab27f8c7/nixos/modules/config/nix.nix#L114
+# to remove warnings about deprecated nix command
+SHOW_CONFIG_COMMAND = (
+    nix_raw(
+        [
+            'eval',
+            '--impure',
+            '--expr',
+            'if builtins.compareVersions builtins.nixVersion "2.20pre" == -1 then "show-config" else "config show"',
+        ],
+        extra_flags=[],
+    )
+    .decode('utf8')
+    .strip()
+    .replace('"', '')
+)
+
 USER = pwd.getpwuid(os.getuid())[0]
 USER_IS_ROOT = os.geteuid() == 0
 
@@ -98,9 +115,11 @@ def nix_raw(
 def check_substituters() -> Tuple[bool, bool]:
     global TRUSTED_USERS, CURRENT_SUBSTITUTERS, CURRENT_TRUSTED_PUBLIC_KEYS, CURRENT_NETRC_FILE
     try:
-        result = nix_raw(['show-config', '--json'], extra_flags=[])
+        cmd = SHOW_CONFIG_COMMAND.split()
+        cmd.append('--json')
+        result = nix_raw(cmd, extra_flags=[])
     except Exception:
-        rich.print("⚠️ [yellow]Could not run 'nix show-config'.")
+        rich.print(f"⚠️ [yellow]Could not run 'nix {SHOW_CONFIG_COMMAND}'.")
         return False, False
     config = json.loads(result)
     try:

src/kup/package.py

@@ -165,7 +165,7 @@ def __init__(
         github_package: GithubPackage,
         package_name: PackageName,
         path: str,
-        index: int = -1,
+        index: Union[int, str] = -1,
     ):
         self.path = path
         self.index = index
@@ -237,7 +237,7 @@ def __init__(
         status: str,
         commit: str,
         tag: Optional[str] = None,
-        index: int = -1,
+        index: Union[int, str] = -1,
         ssh_git: bool = False,
         access_token: Optional[str] = None,
         substituters: Optional[list[str]] = None,
@@ -283,7 +283,7 @@ def concrete(
             )
 
     @staticmethod
-    def parse(url: str, package: GithubPackage, idx: int, load_versions: bool) -> 'ConcretePackage':
+    def parse(url: str, package: GithubPackage, idx: Union[int, str], load_versions: bool) -> 'ConcretePackage':
         global tag_cache
         if package.ssh_git:
             commit = url.split('&rev=')[1]