Raise errors from threads in whitenoise.compress (#615)

docs/changelog.rst

@@ -2,6 +2,14 @@
 Changelog
 =========
 
+Unreleased
+----------
+
+* Raise any errors from threads in the ``whitenoise.compress`` command.
+
+  Regression in 6.8.0.
+  Thanks to Tom Grainger for the spotting this with a `comment on PR #484 <https://github.com/evansd/whitenoise/pull/484#discussion_r1818989096>`__.
+
 6.8.0 (2024-10-28)
 ------------------
 

src/whitenoise/compress.py

@@ -5,6 +5,7 @@
 import os
 import re
 from concurrent.futures import ThreadPoolExecutor
+from concurrent.futures import as_completed
 from io import BytesIO
 
 try:
@@ -181,12 +182,18 @@ def main(argv=None):
     )
 
     with ThreadPoolExecutor() as executor:
+        futures = []
         for dirpath, _dirs, files in os.walk(args.root):
             for filename in files:
                 if compressor.should_compress(filename):
-                    executor.submit(
-                        compressor.compress, os.path.join(dirpath, filename)
+                    futures.append(
+                        executor.submit(
+                            compressor.compress, os.path.join(dirpath, filename)
+                        )
                     )
+        # Trigger any errors
+        for future in as_completed(futures):
+            future.result()
 
     return 0
 

tests/test_compress.py

@@ -6,6 +6,7 @@
 import re
 import shutil
 import tempfile
+from unittest import mock
 
 import pytest
 
@@ -84,3 +85,13 @@ def test_compressed_effectively_no_orig_size():
     assert not compressor.is_compressed_effectively(
         "test_encoding", "test_path", 0, "test_data"
     )
+
+
+def test_main_error(files_dir):
+    with (
+        pytest.raises(ValueError) as excinfo,
+        mock.patch.object(Compressor, "compress", side_effect=ValueError("woops")),
+    ):
+        compress_main([files_dir, "--quiet"])
+
+    assert excinfo.value.args == ("woops",)