git/fetch-pack.h, branch v2.30.2

Merge branch 'jt/lazy-fetch'

2020-09-03T19:37:04Z

Updates to on-demand fetching code in lazily cloned repositories. * jt/lazy-fetch: fetch: no FETCH_HEAD display if --no-write-fetch-head fetch-pack: remove no_dependents code promisor-remote: lazy-fetch objects in subprocess fetch-pack: do not lazy-fetch during ref iteration fetch: only populate existing_refs if needed fetch: avoid reading submodule config until needed fetch: allow refspecs specified through stdin negotiator/noop: add noop fetch negotiator

(various): document from_promisor parameter

2020-08-25T00:30:08Z

88e2f9ed8e ("introduce fetch-object: fetch one promisor object", 2017-12-05) plumbed through the from_promisor parameter but did not document it everywhere it appeared. Add the documentation. (It also plumbed through the no_dependents parameter, but I have left that alone because it is being removed in a commit under review [1].) [1] https://lore.kernel.org/git/e8f16d69089a5011c355d5939c56fa53b7a1eb2d.1597184949.git.jonathantanmy@google.com/ Signed-off-by: Jonathan Tan Signed-off-by: Junio C Hamano

fetch-pack: remove no_dependents code

2020-08-18T23:46:53Z

Now that Git has switched to using a subprocess to lazy-fetch missing objects, remove the no_dependents code as it is no longer used. Signed-off-by: Jonathan Tan Signed-off-by: Junio C Hamano

fetch-pack: support more than one pack lockfile

2020-06-11T01:06:34Z

Whenever a fetch results in a packfile being downloaded, a .keep file is generated, so that the packfile can be preserved (from, say, a running "git repack") until refs are written referring to the contents of the packfile. In a subsequent patch, a successful fetch using protocol v2 may result in more than one .keep file being generated. Therefore, teach fetch_pack() and the transport mechanism to support multiple .keep files. Implementation notes: - builtin/fetch-pack.c normally does not generate .keep files, and thus is unaffected by this or future changes. However, it has an undocumented "--lock-pack" feature, used by remote-curl.c when implementing the "fetch" remote helper command. In keeping with the remote helper protocol, only one "lock" line will ever be written; the rest will result in warnings to stderr. However, in practice, warnings will never be written because the remote-curl.c "fetch" is only used for protocol v0/v1 (which will not generate multiple .keep files). (Protocol v2 uses the "stateless-connect" command, not the "fetch" command.) - connected.c has an optimization in that connectivity checks on a ref need not be done if the target object is in a pack known to be self-contained and connected. If there are multiple packfiles, this optimization can no longer be done. Signed-off-by: Jonathan Tan Signed-off-by: Junio C Hamano

fetch_pack(): drop unused parameters

2019-03-20T09:34:09Z

We don't need the caller of fetch_pack() to pass in "dest", which is the remote URL. Since ba227857d2 (Reduce the number of connects when fetching, 2008-02-04), the caller is responsible for calling git_connect() itself, and our "dest" parameter is unused. That commit also started passing us the resulting "conn" child_process from git_connect(). But likewise, we do not need do anything with it. The descriptors in "fd" are enough for us, and the caller is responsible for cleaning up "conn". We can just drop both parameters. Signed-off-by: Jeff King Signed-off-by: Junio C Hamano

fetch-pack: exclude blobs when lazy-fetching trees

2018-10-04T13:03:49Z

A partial clone with missing trees can be obtained using "git clone --filter=tree:none ". In such a repository, when a tree needs to be lazily fetched, any tree or blob it directly or indirectly references is fetched as well, regardless of whether the original command required those objects, or if the local repository already had some of them. This is because the fetch protocol, which the lazy fetch uses, does not allow clients to request that only the wanted objects be sent, which would be the ideal solution. This patch implements a partial solution: specify the "blob:none" filter, somewhat reducing the fetch payload. This change has no effect when lazily fetching blobs (due to how filters work). And if lazily fetching a commit (such repositories are difficult to construct and is not a use case we support very well, but it is possible), referenced commits and trees are still fetched - only the blobs are not fetched. The necessary code change is done in fetch_pack() instead of somewhere closer to where the "filter" instruction is written to the wire so that only one part of the code needs to be changed in order for users of all protocol versions to benefit from this optimization. Signed-off-by: Jonathan Tan Signed-off-by: Junio C Hamano

Merge branch 'jt/fetch-nego-tip'

2018-08-02T22:30:43Z

"git fetch" learned a new option "--negotiation-tip" to limit the set of commits it tells the other end as "have", to reduce wasted bandwidth and cycles, which would be helpful when the receiving repository has a lot of refs that have little to do with the history at the remote it is fetching from. * jt/fetch-nego-tip: fetch-pack: support negotiation tip whitelist

fetch-pack: support negotiation tip whitelist

2018-07-03T22:00:41Z

During negotiation, fetch-pack eventually reports as "have" lines all commits reachable from all refs. Allow the user to restrict the commits sent in this way by providing a whitelist of tips; only the tips themselves and their ancestors will be sent. Both globs and single objects are supported. This feature is only supported for protocols that support connect or stateless-connect (such as HTTP with protocol v2). This will speed up negotiation when the repository has multiple relatively independent branches (for example, when a repository interacts with multiple repositories, such as with linux-next [1] and torvalds/linux [2]), and the user knows which local branch is likely to have commits in common with the upstream branch they are fetching. [1] https://kernel.googlesource.com/pub/scm/linux/kernel/git/next/linux-next/ [2] https://kernel.googlesource.com/pub/scm/linux/kernel/git/torvalds/linux/ Signed-off-by: Jonathan Tan 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

fetch: send server options when using protocol v2

2018-04-24T02:24:40Z

Teach fetch to optionally accept server options by specifying them on the cmdline via '-o' or '--server-option'. These server options are sent to the remote end when performing a fetch communicating using protocol version 2. If communicating using a protocol other than v2 the provided options are ignored and not sent to the remote end. Signed-off-by: Brandon Williams Signed-off-by: Junio C Hamano