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Author	SHA1	Message	Date
Junio C Hamano	d21c463d55	fetch/receive: remove over-pessimistic connectivity check Git 1.7.8 introduced an object and history re-validation step after "fetch" or "push" causes new history to be added to a receiving repository. This is to protect a malicious server or pushing client from corrupting the repository by taking advantage of an existing corrupt object that is unconnected to existing history. But this check is way over-pessimistic. During "fetch" or "receive-pack" (the server side of "push"), unpack-objects and index-pack already validate individual objects that are received, and the only thing we would want to catch are corrupted objects that already happen to exist in our repository but are not referenced from our refs. Such objects must have been written by an earlier run of our codepaths that write out loose objects or packfiles, and they must have done the validation of individual objects when they did so. The only thing left to worry about is the connectivity integrity, which can be checked with "rev-list --objects", which is much cheaper. We have been paying the 5x to 8x runtime overhead the --verify-objects often adds for no real gain. Revert check_everything_connected() not to use this over-pessimistic check. Credit goes to Nguyễn Thái Ngọc Duy, who originally identified the performance regression and endured multiple rounds of reviews to fix it. Signed-off-by: Junio C Hamano <gitster@pobox.com>	13 years ago
Junio C Hamano	f96400cb46	check_everything_connected(): libify Extract the helper function and the type definition of the iterator function it uses out of builtin/fetch.c into a separate source and a header file. Signed-off-by: Junio C Hamano <gitster@pobox.com>	14 years ago

Author

SHA1

Message

Date

Junio C Hamano

d21c463d55

fetch/receive: remove over-pessimistic connectivity check

Git 1.7.8 introduced an object and history re-validation step after
"fetch" or "push" causes new history to be added to a receiving
repository. This is to protect a malicious server or pushing client from
corrupting the repository by taking advantage of an existing corrupt
object that is unconnected to existing history.

But this check is way over-pessimistic.  During "fetch" or "receive-pack"
(the server side of "push"), unpack-objects and index-pack already
validate individual objects that are received, and the only thing we would
want to catch are corrupted objects that already happen to exist in our
repository but are not referenced from our refs.  Such objects must have
been written by an earlier run of our codepaths that write out loose
objects or packfiles, and they must have done the validation of individual
objects when they did so.  The only thing left to worry about is the
connectivity integrity, which can be checked with "rev-list --objects",
which is much cheaper.  We have been paying the 5x to 8x runtime overhead
the --verify-objects often adds for no real gain.

Revert check_everything_connected() not to use this over-pessimistic
check.

Credit goes to Nguyễn Thái Ngọc Duy, who originally identified the
performance regression and endured multiple rounds of reviews to fix it.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

13 years ago

Junio C Hamano

f96400cb46

check_everything_connected(): libify

Extract the helper function and the type definition of the iterator
function it uses out of builtin/fetch.c into a separate source and a
header file.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

14 years ago

2 Commits (a2f7b6f8a9775df0994a161f5e9e103b60886dc7)