fix(sources): skip non-regular files in scan_compiled_extensions

pathlib.Path.walk() lists symlinks to directories as filenames rather
than dirnames. This causes scan_compiled_extensions to attempt to
open() them, resulting in IsADirectoryError. Add an is_file() check
to skip non-regular files before attempting to read their contents.

Closes: #1001
Closes: #1004
Co-Authored-By: Mike DePaulo <mikedep333@redhat.com>
Co-Authored-By: Claude Opus 4.6 <claude@anthropic.com>
Signed-off-by: pmattsso <pmattsso@redhat.com>

Author: 2 people

src/fromager/sources.py

@@ -865,6 +865,10 @@ def scan_compiled_extensions(
                 logger.debug("file %s has a binary extension suffix", relpath)
                 issues.append(relpath)
             elif suffix not in ignore_suffixes:
+                # Path.walk() lists symlinks to directories as filenames
+                # rather than dirnames, causing IsADirectoryError on open().
+                if not filepath.is_file():
+                    continue
                 with filepath.open("rb") as f:
                     header = f.read(_MAGIC_HEADERS_READ)
                 if header.startswith(magic_headers):