Issue #23347, asyncio: send_signal(), terminate(), kill() don't check if the

transport was closed. The check broken a Tulip example and this limitation is
arbitrary. Check if _proc is None should be enough.

Enhance also close(): do nothing when called the second time.

1 files changed, 3 insertions, 4 deletions

diff --git a/Lib/asyncio/base_subprocess.py b/Lib/asyncio/base_subprocess.py
index 70676ab..02b9e89 100644
--- a/Lib/asyncio/base_subprocess.py
+++ b/Lib/asyncio/base_subprocess.py
@@ -84,6 +84,8 @@ class BaseSubprocessTransport(transports.SubprocessTransport):
         raise NotImplementedError
 
     def close(self):
+        if self._closed:
+            return
         self._closed = True
 
         for proto in self._pipes.values():
@@ -100,8 +102,7 @@ class BaseSubprocessTransport(transports.SubprocessTransport):
             except ProcessLookupError:
                 pass
 
-            # Don't clear the _proc reference yet because _post_init() may
-            # still run
+            # Don't clear the _proc reference yet: _post_init() may still run
 
     # On Python 3.3 and older, objects with a destructor part of a reference
     # cycle are never destroyed. It's not more the case on Python 3.4 thanks
@@ -125,8 +126,6 @@ class BaseSubprocessTransport(transports.SubprocessTransport):
             return None
 
     def _check_proc(self):
-        if self._closed:
-            raise ValueError("operation on closed transport")
         if self._proc is None:
             raise ProcessLookupError()