Support zstd-compressed SBOM

CHANGELOG.md

@@ -6,6 +6,8 @@ All notable changes to this project will be documented in this file.
 
 ### Added
 
+ - Support zstd-compressed SPDX files.
+
 ### Changed
 
 - Add custom `HelpFormatter` to render boolean flags in a compact `--[no-]flag` format instead of the default `--flag, --no-flag`.

pyproject.toml

@@ -20,6 +20,10 @@ classifiers = [
     "Topic :: Software Development :: Build Tools",
 ]
 
+dependencies = [
+    "backports.zstd; python_version < '3.14'"
+]
+
 [project.scripts]
 spdx-diff = "spdx_diff.cli:main"
 

src/spdx_diff/cli.py

@@ -16,6 +16,11 @@
 from collections import defaultdict
 from typing import Any
 
+if sys.version_info >= (3, 14):
+    from compression import zstd
+else:
+    from backports import zstd
+
 from . import __version__
 
 _logger = logging.getLogger(__name__)
@@ -53,9 +58,14 @@ def _parse(self, json_path: pathlib.Path) -> None:
         :param json_path: Path the JSON file.
         """
         _logger.info("Opening SPDX file: %s", json_path)
+
         try:
-            with json_path.open(encoding="utf-8") as f:
-                data = json.load(f)
+            if json_path.suffix == ".zst":
+                with zstd.open(json_path, "rt") as f:
+                    data = json.load(f)
+            else:
+                with json_path.open(encoding="utf-8") as f:
+                    data = json.load(f)
         except (OSError, ValueError) as e:
             raise ValueError("Failed to read or parse %s", json_path) from e