From 7fb8e163bdfdc5ffb69b98f3f05ef0dbade4e677 Mon Sep 17 00:00:00 2001 From: Pete Wyckoff Date: Sun, 22 Apr 2012 16:30:58 -0400 Subject: git-remote-testgit: fix race when spawning fast-import Test "pushing to local repo" in t5800-remote-helpers can hang due to a race condition in git-remote-testgit. Fix it by setting stdin to unbuffered. On the writer side, "git push" invokes push_refs_with_export(), which sends to stdout the command "export\n" and immediately starts up "git fast-export". The latter writes its output stream to the same stdout. On the reader side, remote helper "git-remote-testgit" reads from stdin to get its next command. It uses getc() to read characters from libc up until \n. Libc has buffered a potentially much larger chunk of stdin. When it sees the "export\n" command, it forks "git fast-import" to read the stream. If fast-export finishes before git fast-import starts, the fast-export output can end up in libc's buffer in git-remote-testgit, rather than in git fast-import. The latter hangs indefinitely on a now-empty stdin. Signed-off-by: Pete Wyckoff Signed-off-by: Junio C Hamano --- git-remote-testgit.py | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'git-remote-testgit.py') diff --git a/git-remote-testgit.py b/git-remote-testgit.py index 3dc4851cfc..5f3ebd244d 100644 --- a/git-remote-testgit.py +++ b/git-remote-testgit.py @@ -22,6 +22,7 @@ except ImportError: _digest = sha.new import sys import os +import time sys.path.insert(0, os.getenv("GITPYTHONLIB",".")) from git_remote_helpers.util import die, debug, warn @@ -204,6 +205,11 @@ def read_one_line(repo): """Reads and processes one command. """ + sleepy = os.environ.get("GIT_REMOTE_TESTGIT_SLEEPY") + if sleepy: + debug("Sleeping %d sec before readline" % int(sleepy)) + time.sleep(int(sleepy)) + line = sys.stdin.readline() cmdline = line @@ -258,6 +264,7 @@ def main(args): more = True + sys.stdin = os.fdopen(sys.stdin.fileno(), 'r', 0) while (more): more = read_one_line(repo) -- cgit v1.2.3