Since bad input causes py_compile.py to issue an error like this:

  File "/usr/local/Cellar/python@3.8/3.8.3/Frameworks/Python.framework/Versions/3.8/lib/python3.8/py_compile.py", line 213, in main
    if quiet < 2:
NameError: name 'quiet' is not defined

I suggest, to save long review of a larger PR elsewhere, can we please just initially apply a patch like this:

[~/src/cpython(git:py_compile-quiet-not-initialised)]fleet2*> diff
+ exec git diff
diff --git a/Lib/py_compile.py b/Lib/py_compile.py
index 21736896af..cea851274d 100644
--- a/Lib/py_compile.py
+++ b/Lib/py_compile.py
@@ -186,6 +186,7 @@ def main(args=None):
     """
     if args is None:
         args = sys.argv[1:]
+    quiet = 0
     rv = 0
     if args == ['-']:
         while True:

Then the runtime issue goes away, and adding the feature fully can be addressed in a more leisurely fashion.