diff options
| author | Pete Wyckoff <pw@padd.com> | 2012-04-23 00:30:58 +0400 |
|---|---|---|
| committer | Junio C Hamano <gitster@pobox.com> | 2012-04-25 01:54:24 +0400 |
| commit | 7fb8e163bdfdc5ffb69b98f3f05ef0dbade4e677 (patch) | |
| tree | fd59cfc42d64520337820b4485c744096db4d4fd | |
| parent | fdec2eb8ebbf995a77e2ab9971565c792b52944a (diff) | |
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 <pw@padd.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
| -rw-r--r-- | git-remote-testgit.py | 7 | ||||
| -rwxr-xr-x | t/t5800-remote-helpers.sh | 13 |
2 files changed, 20 insertions, 0 deletions
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) diff --git a/t/t5800-remote-helpers.sh b/t/t5800-remote-helpers.sh index 1c62001fce..5702334510 100755 --- a/t/t5800-remote-helpers.sh +++ b/t/t5800-remote-helpers.sh @@ -72,6 +72,19 @@ test_expect_success 'pushing to local repo' ' compare_refs localclone HEAD server HEAD ' +# Generally, skip this test. It demonstrates a now-fixed race in +# git-remote-testgit, but is too slow to leave in for general use. +: test_expect_success 'racily pushing to local repo' ' + test_when_finished "rm -rf server2 localclone2" && + cp -a server server2 && + git clone "testgit::${PWD}/server2" localclone2 && + (cd localclone2 && + echo content >>file && + git commit -a -m three && + GIT_REMOTE_TESTGIT_SLEEPY=2 git push) && + compare_refs localclone2 HEAD server2 HEAD +' + test_expect_success 'synch with changes from localclone' ' (cd clone && git pull) |