diff --git a/scripts/filter_lint_by_diff.py b/scripts/filter_lint_by_diff.py
index 534c642a6ba..7a4c506e27e 100755
--- a/scripts/filter_lint_by_diff.py
+++ b/scripts/filter_lint_by_diff.py
@@ -11,20 +11,19 @@
 added_lines = set()
 repository_root = sys.argv[2]
 
-with open(sys.argv[1], "r") as f:
-  diff = unidiff.PatchSet(f)
-  for diff_file in diff:
-    filename = diff_file.target_file
-    # Skip files deleted in the tip (b side of the diff):
-    if filename == "/dev/null":
-      continue
-    assert filename.startswith("b/")
-    filename = os.path.join(repository_root, filename[2:])
-    added_lines.add((filename, 0))
-    for diff_hunk in diff_file:
-      for diff_line in diff_hunk:
-        if diff_line.line_type == "+":
-          added_lines.add((filename, diff_line.target_line_no))
+diff = unidiff.PatchSet.from_filename(sys.argv[1])
+for diff_file in diff:
+  filename = diff_file.target_file
+  # Skip files deleted in the tip (b side of the diff):
+  if filename == "/dev/null":
+    continue
+  assert filename.startswith("b/")
+  filename = os.path.join(repository_root, filename[2:])
+  added_lines.add((filename, 0))
+  for diff_hunk in diff_file:
+    for diff_line in diff_hunk:
+      if diff_line.line_type == "+":
+        added_lines.add((filename, diff_line.target_line_no))
 
 for l in sys.stdin:
   bits = l.split(":")