diff --git a/Lib/subprocess.py b/Lib/subprocess.py index 7c7ee51f514..6911cd8e859 100644 --- a/Lib/subprocess.py +++ b/Lib/subprocess.py @@ -2097,6 +2097,10 @@ class Popen: self.stdin.flush() except BrokenPipeError: pass # communicate() must ignore BrokenPipeError. + except ValueError: + # ignore ValueError: I/O operation on closed file. + if not self.stdin.closed: + raise if not input: try: self.stdin.close() diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py index b869e30135e..806a1e3fa30 100644 --- a/Lib/test/test_subprocess.py +++ b/Lib/test/test_subprocess.py @@ -1160,6 +1160,19 @@ class ProcessTestCase(BaseTestCase): self.assertEqual(stdout, b"bananasplit") self.assertEqual(stderr, b"") + def test_communicate_stdin_closed_before_call(self): + # gh-70560, gh-74389: stdin.close() before communicate() + # should not raise ValueError from stdin.flush() + with subprocess.Popen([sys.executable, "-c", + 'import sys; sys.exit(0)'], + stdin=subprocess.PIPE, + stdout=subprocess.PIPE, + stderr=subprocess.PIPE) as p: + p.stdin.close() # Close stdin before communicate + # This should not raise ValueError + (stdout, stderr) = p.communicate() + self.assertEqual(p.returncode, 0) + def test_universal_newlines_and_text(self): args = [ sys.executable, "-c", diff --git a/Misc/NEWS.d/next/Library/2025-11-29-04-20-44.gh-issue-74389.pW3URj.rst b/Misc/NEWS.d/next/Library/2025-11-29-04-20-44.gh-issue-74389.pW3URj.rst new file mode 100644 index 00000000000..a9bf5f80d80 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2025-11-29-04-20-44.gh-issue-74389.pW3URj.rst @@ -0,0 +1,3 @@ +When the stdin being used by a :class:`subprocess.Popen` instance is closed, +this is now ignored in :meth:`subprocess.Popen.communicate` instead of +leaving the class in an inconsistent state.