git/connected.h, branch v2.32.2

connected: always use partial clone optimization

2020-03-29T17:37:44Z

With 50033772d5 ("connected: verify promisor-ness of partial clone", 2020-01-30), the fast path (checking promisor packs) in check_connected() now passes a subset of the slow path (rev-list) - if all objects to be checked are found in promisor packs, both the fast path and the slow path will pass; otherwise, the fast path will definitely not pass. This means that we can always attempt the fast path whenever we need to do the slow path. The fast path is currently guarded by a flag; therefore, remove that flag. Also, make the fast path fallback to the slow path - if the fast path fails, the failing OID and all remaining OIDs will be passed to rev-list. The main user-visible benefit is the performance of fetch from a partial clone - specifically, the speedup of the connectivity check done before the fetch. In particular, a no-op fetch into a partial clone on my computer was sped up from 7 seconds to 0.01 seconds. This is a complement to the work in 2df1aa239c ("fetch: forgo full connectivity check if --filter", 2020-01-30), which is the child of the aforementioned 50033772d5. In that commit, the connectivity check *after* the fetch was sped up. The addition of the fast path might cause performance reductions in these cases: - If a partial clone or a fetch into a partial clone fails, Git will fruitlessly run rev-list (it is expected that everything fetched would go into promisor packs, so if that didn't happen, it is most likely that rev-list will fail too). - Any connectivity checks done by receive-pack, in the (in my opinion, unlikely) event that a partial clone serves receive-pack. I think that these cases are rare enough, and the performance reduction in this case minor enough (additional object DB access), that the benefit of avoiding a flag outweighs these. Signed-off-by: Jonathan Tan Reviewed-by: Josh Steadmon Signed-off-by: Junio C Hamano

connected: verify promisor-ness of partial clone

2020-01-30T18:55:31Z

Commit dfa33a298d ("clone: do faster object check for partial clones", 2019-04-21) optimized the connectivity check done when cloning with --filter to check only the existence of objects directly pointed to by refs. But this is not sufficient: they also need to be promisor objects. Make this check more robust by instead checking that these objects are promisor objects, that is, they appear in a promisor pack. Signed-off-by: Jonathan Tan Reviewed-by: Jonathan Nieder Signed-off-by: Junio C Hamano

clone: do faster object check for partial clones

2019-04-21T05:08:53Z

For partial clones, doing a full connectivity check is wasteful; we skip promisor objects (which, for a partial clone, is all known objects), and enumerating them all to exclude them from the connectivity check can take a significant amount of time on large repos. At most, we want to make sure that we get the objects referred to by any wanted refs. For partial clones, just check that these objects were transferred. Signed-off-by: Josh Steadmon Signed-off-by: Junio C Hamano

connected: document connectivity in partial clones

2018-09-21T20:20:47Z

In acb0c57260 ("fetch: support filters", 2017-12-08), check_connected() was extended to allow objects to either be promised to be available (if the repository is a partial clone) or to be present; previously, this function required the latter. However, this change was not reflected in the documentation of that function. Update the documentation accordingly. Signed-off-by: Jonathan Tan Signed-off-by: Junio C Hamano

Add missing includes and forward declarations

2018-08-15T18:52:09Z

I looped over the toplevel header files, creating a temporary two-line C program for each consisting of #include "git-compat-util.h" #include $HEADER This patch is the result of manually fixing errors in compiling those tiny programs. Signed-off-by: Elijah Newren Signed-off-by: Junio C Hamano

fetch-pack: write shallow, then check connectivity

2018-07-03T21:57:44Z

When fetching, connectivity is checked after the shallow file is updated. There are 2 issues with this: (1) the connectivity check is only performed up to ancestors of existing refs (which is not thorough enough if we were deepening an existing ref in the first place), and (2) there is no rollback of the shallow file if the connectivity check fails. To solve (1), update the connectivity check to check the ancestry chain completely in the case of a deepening fetch by refraining from passing "--not --all" when invoking rev-list in connected.c. To solve (2), have fetch_pack() perform its own connectivity check before updating the shallow file. To support existing use cases in which "git fetch-pack" is used to download objects without much regard as to the connectivity of the resulting objects with respect to the existing repository, the connectivity check is only done if necessary (that is, the fetch is not a clone, and the fetch involves shallow/deepen functionality). "git fetch" still performs its own connectivity check, preserving correctness but sometimes performing redundant work. This redundancy is mitigated by the fact that fetch_pack() reports if it has performed a connectivity check itself, and if the transport supports connect or stateless-connect, it will bubble up that report so that "git fetch" knows not to perform the connectivity check in such a case. This was noticed when a user tried to deepen an existing repository by fetching with --no-shallow from a server that did not send all necessary objects - the connectivity check as run by "git fetch" succeeded, but a subsequent "git fsck" failed. Signed-off-by: Jonathan Tan Signed-off-by: Junio C Hamano

Convert check_connected to use struct object_id

2017-10-16T02:05:50Z

Convert check_connected and the callbacks it takes to use struct object_id. Signed-off-by: brian m. carlson Signed-off-by: Junio C Hamano

check_connected: accept an env argument

2016-10-10T20:54:02Z

This lets callers influence the environment seen by rev-list, which will be useful when we start providing quarantined objects. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano

check_connected: add progress flag

2016-07-20T19:11:09Z

Connectivity checks have to traverse the entire object graph in the worst case (e.g., a full clone or a full push). For large repositories like linux.git, this can take 30-60 seconds, during which time git may produce little or no output. Let's add the option of showing progress, which is taken care of by rev-list. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano

check_connected: relay errors to alternate descriptor

2016-07-20T19:11:01Z

Unless the "quiet" flag is given, check_connected sends any errors to the stderr of the caller (because the child rev-list inherits that descriptor). However, server-side callers may want to send these over a sideband channel instead. Let's make that possible. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano