signal errors during black_bindings

Author: jepler

tools/black_bindings.py

@@ -28,7 +28,7 @@ def transform(fn, s):
         )
     except subprocess.CalledProcessError as e:
         print(f"{fn}:0: Failed to process block:\n{s}")
-        return s
+        raise
 
     result = result.stdout[len(prefix) :]
     result = (result.rstrip()).split("\n")
@@ -58,6 +58,11 @@ def process_one_file(fn):
     # Use a thread pool because most processing is inside black!
     executor = ThreadPoolExecutor(max_workers=os.cpu_count())
     futures = [executor.submit(process_one_file, fn) for fn in sys.argv[1:]]
+    status = 0
     for f in futures:
-        f.result()
+        try:
+            f.result()
+        except Exception as e:
+            status = 1
     executor.shutdown()
+    raise SystemExit(status)