libxcrypt: Add check for enabledCryptSchemeIds

pkgs/development/libraries/libxcrypt/check_passthru_matches.py

···
+import tarfile
+import sys
+
+
+def process_columns(line: list[str]) -> tuple[str, list[str]]:
+    match line:
+        case [name, h_prefix, nrbytes, flags]:
+            return (h_prefix, flags.lower().split(","))
+        case other:
+            raise Exception("Unsupported hashes.conf line format", other)
+
+
+def find_tar_file(tar: tarfile.TarFile, requested_name: str):
+    """Attempts to find a single file with given name in tarball."""
+    all_names = tar.getnames()
+
+    if requested_name in all_names:
+        return requested_name
+
+    requested_suffix = f"/{requested_name}"
+    candidate_names = [name for name in all_names if name.endswith(requested_suffix)]
+    match candidate_names:
+        case [real_name]:
+            return real_name
+        case other:
+            raise KeyError(
+                f"Could not locate a single {requested_name} in the contents of the tarball."
+            )
+
+
+hashes_path = "lib/hashes.conf"
+
+
+def main() -> None:
+    match sys.argv:
+        case [_name, src, enable_hashes, "--", *enabled_crypt_scheme_ids]:
+            pass
+        case other:
+            raise Exception(
+                "Incorrect number of arguments. Usage: check_passthru_matches.py <src> <enable_hashes> -- <enabled_crypt_scheme_ids...>"
+            )
+
+    with tarfile.open(src, "r") as tar:
+        real_hashes_path = find_tar_file(tar, hashes_path)
+        config = tar.extractfile(real_hashes_path).read().decode("utf-8")
+
+    formats = [
+        process_columns(columns)
+        for line in config.splitlines()
+        if not line.startswith("#") and len(columns := line.split()) > 0
+    ]
+    expected_supported_formats = set(
+        prefix
+        for (prefix, flags) in formats
+        if enable_hashes in flags or enable_hashes == "all"
+    )
+    passthru_supported_schemes = set(
+        f"${scheme}$" for scheme in enabled_crypt_scheme_ids
+    )
+
+    assert (
+        len(expected_supported_formats - passthru_supported_schemes) == 0
+    ), f"libxcrypt package enables the following crypt schemes that are not listed in passthru.enabledCryptSchemeIds: {expected_supported_formats - passthru_supported_schemes}"
+    assert (
+        len(passthru_supported_schemes - expected_supported_formats) == 0
+    ), f"libxcrypt package lists the following crypt schemes in passthru.enabledCryptSchemeIds that are not supported: {passthru_supported_schemes - expected_supported_formats}"
+
+
+if __name__ == "__main__":
+    main()

pkgs/development/libraries/libxcrypt/default.nix

···
 # Update the enabled crypt scheme ids in passthru when the enabled hashes change
 , enableHashes ? "strong"
 , nixosTests
+, runCommand
+, python3
 }:
 
-stdenv.mkDerivation rec {
+stdenv.mkDerivation (finalAttrs: {
   pname = "libxcrypt";
   version = "4.4.33";
 
   src = fetchurl {
-    url = "https://github.com/besser82/libxcrypt/releases/download/v${version}/libxcrypt-${version}.tar.xz";
+    url = "https://github.com/besser82/libxcrypt/releases/download/v${finalAttrs.version}/libxcrypt-${finalAttrs.version}.tar.xz";
     hash = "sha256-6HrPnGUsVzpHE9VYIVn5jzBdVu1fdUzmT1fUGU1rOm8=";
   };
 
···
   passthru = {
     tests = {
       inherit (nixosTests) login shadow;
+
+      passthruMatches = runCommand "libxcrypt-test-passthru-matches" { } ''
+        ${python3.interpreter} "${./check_passthru_matches.py}" ${lib.escapeShellArgs ([ finalAttrs.src enableHashes "--" ] ++ finalAttrs.passthru.enabledCryptSchemeIds)}
+        touch "$out"
+      '';
     };
     enabledCryptSchemeIds = [
       # https://github.com/besser82/libxcrypt/blob/v4.4.33/lib/hashes.conf
···
     maintainers = with maintainers; [ dottedmag hexa ];
     license = licenses.lgpl21Plus;
   };
-}
+})