git/t/t5527-fetch-odd-refs.sh
Jeff King 8e9faf27c1 pkt-line: allow writing of LARGE_PACKET_MAX buffers
When we send out pkt-lines with refnames, we use a static
1000-byte buffer. This means that the maximum size of a ref
over the git protocol is around 950 bytes (the exact size
depends on the protocol line being written, but figure on a sha1
plus some boilerplate).

This is enough for any sane workflow, but occasionally odd
things happen (e.g., a bug may create a ref "foo/foo/foo/..."
accidentally).  With the current code, you cannot even use
"push" to delete such a ref from a remote.

Let's switch to using a strbuf, with a hard-limit of
LARGE_PACKET_MAX (which is specified by the protocol).  This
matches the size of the readers, as of 74543a0 (pkt-line:
provide a LARGE_PACKET_MAX static buffer, 2013-02-20).
Versions of git older than that will complain about our
large packets, but it's really no worse than the current
behavior. Right now the sender barfs with "impossibly long
line" trying to send the packet, and afterwards the reader
will barf with "protocol error: bad line length %d", which
is arguably better anyway.

Note that we're not really _solving_ the problem here, but
just bumping the limits. In theory, the length of a ref is
unbounded, and pkt-line can only represent sizes up to
65531 bytes. So we are just bumping the limit, not removing
it.  But hopefully 64K should be enough for anyone.

As a bonus, by using a strbuf for the formatting we can
eliminate an unnecessary copy in format_buf_write.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-12-10 13:09:21 -08:00

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#!/bin/sh
test_description='test fetching of oddly-named refs'
. ./test-lib.sh
# afterwards we will have:
# HEAD - two
# refs/for/refs/heads/master - one
# refs/heads/master - three
test_expect_success 'setup repo with odd suffix ref' '
echo content >file &&
git add . &&
git commit -m one &&
git update-ref refs/for/refs/heads/master HEAD &&
echo content >>file &&
git commit -a -m two &&
echo content >>file &&
git commit -a -m three &&
git checkout HEAD^
'
test_expect_success 'suffix ref is ignored during fetch' '
git clone --bare file://"$PWD" suffix &&
echo three >expect &&
git --git-dir=suffix log -1 --format=%s refs/heads/master >actual &&
test_cmp expect actual
'
test_expect_success 'try to create repo with absurdly long refname' '
ref240=$_z40/$_z40/$_z40/$_z40/$_z40/$_z40 &&
ref1440=$ref240/$ref240/$ref240/$ref240/$ref240/$ref240 &&
git init long &&
(
cd long &&
test_commit long &&
test_commit master
) &&
if git -C long update-ref refs/heads/$ref1440 long; then
test_set_prereq LONG_REF
else
echo >&2 "long refs not supported"
fi
'
test_expect_success LONG_REF 'fetch handles extremely long refname' '
git fetch long refs/heads/*:refs/remotes/long/* &&
cat >expect <<-\EOF &&
long
master
EOF
git for-each-ref --format="%(subject)" refs/remotes/long >actual &&
test_cmp expect actual
'
test_expect_success LONG_REF 'push handles extremely long refname' '
git push long :refs/heads/$ref1440 &&
git -C long for-each-ref --format="%(subject)" refs/heads >actual &&
echo master >expect &&
test_cmp expect actual
'
test_done