view tests/notcapable @ 33668:cde4cfeb6e3e stable

ui: restore behavior to ignore some I/O errors (issue5658)

e9646ff34d55 and 1bfb9a63b98e refactored ui methods to no longer
silently swallow some IOError instances. This is arguably the
correct thing to do. However, it had the unfortunate side-effect
of causing StdioError to bubble up to sensitive code like
transaction aborts, leading to an uncaught exceptions and failures
to e.g. roll back a transaction. This could occur when a remote
HTTP or SSH client connection dropped. The new behavior is
resulting in semi-frequent "abandonded transaction" errors on
multiple high-volume repositories at Mozilla.

This commit effectively reverts e9646ff34d55 and 1bfb9a63b98e to
restore the old behavior.

I agree with the principle that I/O errors shouldn't be ignored.
That makes this change... unfortunate. However, our hands are tied
for what to do on stable. I think the proper solution is for the
ui's behavior to be configurable (possibly via a context manager).
During critical sections like transaction rollback and abort, it
should be possible to suppress errors. But this feature would not
be appropriate on stable.

# Disable the $CAP wire protocol capability.

if test -z "$CAP"
then
    echo "CAP environment variable not set."
fi

cat > notcapable-$CAP.py << EOF
from mercurial import extensions, peer, localrepo
def extsetup():
    extensions.wrapfunction(peer.peerrepository, 'capable', wrapcapable)
    extensions.wrapfunction(localrepo.localrepository, 'peer', wrappeer)
def wrapcapable(orig, self, name, *args, **kwargs):
    if name in '$CAP'.split(' '):
        return False
    return orig(self, name, *args, **kwargs)
def wrappeer(orig, self):
    # Since we're disabling some newer features, we need to make sure local
    # repos add in the legacy features again.
    return localrepo.locallegacypeer(self)
EOF

echo '[extensions]' >> $HGRCPATH
echo "notcapable-$CAP = `pwd`/notcapable-$CAP.py" >> $HGRCPATH