gh-109709: Fix asyncio test_stdin_broken_pipe() (#109710)

Replace harcoded sleep of 500 ms with synchronization using a pipe.

Fix also Process._feed_stdin(): catch also BrokenPipeError on
stdin.write(input), not only on stdin.drain().

1 files changed, 8 insertions, 6 deletions

diff --git a/Lib/asyncio/subprocess.py b/Lib/asyncio/subprocess.py
index c4e5ba2..043359b 100644
--- a/Lib/asyncio/subprocess.py
+++ b/Lib/asyncio/subprocess.py
@@ -147,15 +147,17 @@ class Process:
 
     async def _feed_stdin(self, input):
         debug = self._loop.get_debug()
-        if input is not None:
-            self.stdin.write(input)
-            if debug:
-                logger.debug(
-                    '%r communicate: feed stdin (%s bytes)', self, len(input))
         try:
+            if input is not None:
+                self.stdin.write(input)
+                if debug:
+                    logger.debug(
+                        '%r communicate: feed stdin (%s bytes)', self, len(input))
+
             await self.stdin.drain()
         except (BrokenPipeError, ConnectionResetError) as exc:
-            # communicate() ignores BrokenPipeError and ConnectionResetError
+            # communicate() ignores BrokenPipeError and ConnectionResetError.
+            # write() and drain() can raise these exceptions.
             if debug:
                 logger.debug('%r communicate: stdin got %r', self, exc)