Teach Git to lazy-fetch missing objects in a subprocess instead of doing
it in-process. This allows any fatal errors that occur during the fetch
to be isolated and converted into an error return value, instead of
causing the current command being run to terminate.
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git diff" in a partial clone learned to avoid lazy loading blob
objects in more casese when they are not needed.
* jt/avoid-prefetch-when-able-in-diff:
diff: restrict when prefetching occurs
diff: refactor object read
diff: make diff_populate_filespec_options struct
promisor-remote: accept 0 as oid_nr in function
We return the length to a subset of a string using an "int *"
out-parameter. This is fine most of the time, as we'd expect config keys
to be relatively short, but it could behave oddly if we had a gigantic
config key. A more appropriate type is size_t.
Let's switch over, which lets our callers use size_t as appropriate
(they are bound by our type because they must pass the out-parameter as
a pointer). This is mostly just a cleanup to make it clear this code
handles long strings correctly. In practice, our config parser already
chokes on long key names (because of a similar int/size_t mixup!).
When doing an int/size_t conversion, we have to be careful that nobody
was trying to assign a negative value to the variable. I manually
confirmed that for each case here. They tend to just feed the result to
xmemdupz() or similar; in a few cases I adjusted the parameter types for
helper functions to make sure the size_t is preserved.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There are 3 callers to promisor_remote_get_direct() that first check if
the number of objects to be fetched is equal to 0. Fold that check into
promisor_remote_get_direct(), and in doing so, be explicit as to what
promisor_remote_get_direct() does if oid_nr is 0 (it returns 0, success,
immediately).
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Commit 6462d5eb9a ("fetch: remove fetch_if_missing=0", 2019-11-08)
strove to remove the need for fetch_if_missing=0 from the fetching
mechanism, so it is plausible to attempt removing fetch_if_missing=0
from the lazy-fetching mechanism in promisor-remote as well.
But doing so reveals a bug - when the server does not send an object
pointed to by a tag object, an infinite loop occurs: Git attempts to
fetch the missing object, which causes a deferencing of all refs (for
negotiation), which causes a lazy fetch of that missing object, and so
on. This bug is because of unnecessary use of the fetch negotiator
during lazy fetching - it is not used after initialization, but it is
still initialized (which causes the dereferencing of all refs).
Thus, when the negotiator is not used during fetching, refrain from
initializing it. Then, remove fetch_if_missing from promisor-remote.
Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Previously, when promisor_remote_move_to_tail() is called for a
promisor_remote which is currently the final element in promisors, a
cycle is created in the promisors linked list. This cycle leads to a
double free later on in promisor_remote_clear() when the final element
of the promisors list is removed: promisors is set to promisors->next (a
no-op, as promisors->next == promisors); the previous value of promisors
is free()'d; then the new value of promisors (which is equal to the
previous value of promisors) is also free()'d. This double-free error
was unrecoverable for the user without removing the filter or re-cloning
the repo and hoping to miss this edge case.
Now, when promisor_remote_move_to_tail() would be a no-op, just do a
no-op. In cases of promisor_remote_move_to_tail() where r is not already
at the tail of the list, it works as before.
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Emily Shaffer <emilyshaffer@google.com>
Acked-by: Christian Couder <christian.couder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Now that we can have a different default partial clone filter for
each promisor remote, let's hide core_partial_clone_filter_default
as a static in promisor-remote.c to avoid it being use for
anything other than managing backward compatibility.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Now that we have has_promisor_remote() and can use many
promisor remotes, let's hide repository_format_partial_clone
as a static in promisor-remote.c to avoid it being use
for anything other than managing backward compatibility.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
As fetch_objects() is now used only in promisor-remote.c
and should't be used outside it, let's move it into
promisor-remote.c, make it static there, and remove
fetch-object.{c,h}.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This makes it possible to specify a different partial clone
filter for each promisor remote.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A remote specified using the extensions.partialClone config
option should be considered a promisor remote too.
For simplicity and to make things predictable, this promisor
remote should be either always the last one we try to get
objects from, or the first one. So it should always be either
at the end of the promisor remote list, or at its start.
We decided to make it the last one we try, because it is
likely that someone using many promisor remotes is doing so
because the other promisor remotes are better for some reason
(maybe they are closer or faster for some kind of objects)
than the origin, and the origin is likely to be the remote
specified by extensions.partialClone.
This justification is not very strong, but one choice had to
be made, and anyway the long term plan should be to make the
order somehow fully configurable.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
We will need to reinitialize the promisor remote configuration
as we will make some changes to it in a later commit.
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This is implemented for now by calling fetch_objects(). It fetches
from all the promisor remotes.
Helped-by: Ramsay Jones <ramsay@ramsayjones.plus.com>
Helped-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The promisor-remote.{c,h} files will contain functions to
manage many promisor remotes.
We expect that there will not be a lot of promisor remotes,
so it is ok to use a simple linked list to manage them.
Helped-by: Jeff King <peff@peff.net>
Helped-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Christian Couder <chriscool@tuxfamily.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Jonathan Tan
Junio C Hamano
Jeff King
Emily Shaffer
Christian Couder