fix: write debug log for binary files (#190)

* fix: write debug log for binary files

It took several hours to find out why package-lock.json file was not being scanned. Turns out it was marked a binary and therefore was skipped. Verbose logging would have saved tons of time.

* fix lint issue

Co-authored-by: Joey Wilhelm <tarkatronic@gmail.com>

tartufo/scanner.py

@@ -388,10 +388,11 @@ def _iter_diff_index(
         """
         diff: git.Diff
         for diff in diff_index:
+            file_path = diff.b_path if diff.b_path else diff.a_path
             printable_diff: str = diff.diff.decode("utf-8", errors="replace")
             if printable_diff.startswith("Binary files"):
+                self.logger.debug("Binary file skipped: %s", file_path)
                 continue
-            file_path = diff.b_path if diff.b_path else diff.a_path
             if self.should_scan(file_path):
                 yield (printable_diff, file_path)