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2022-03-28fetch-pack: add refetchLibravatar Robert Coup1-0/+1
Allow a "refetch" where the contents of the local object store are ignored and a full fetch is performed, not attempting to find or negotiate common commits with the remote. A key use case is to apply a new partial clone blob/tree filter and refetch all the associated matching content, which would otherwise not be transferred when the commit objects are already present locally. Signed-off-by: Robert Coup <robert@coup.net.nz> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-05-05fetch: teach independent negotiation (no packfile)Libravatar Jonathan Tan1-0/+14
Currently, the packfile negotiation step within a Git fetch cannot be done independent of sending the packfile, even though there is at least one application wherein this is useful. Therefore, make it possible for this negotiation step to be done independently. A subsequent commit will use this for one such application - push negotiation. This feature is for protocol v2 only. (An implementation for protocol v0 would require a separate implementation in the fetch, transport, and transport helper code.) In the protocol, the main hindrance towards independent negotiation is that the server can unilaterally decide to send the packfile. This is solved by a "wait-for-done" argument: the server will then wait for the client to say "done". In practice, the client will never say it; instead it will cease requests once it is satisfied. In the client, the main change lies in the transport and transport helper code. fetch_refs_via_pack() performs everything needed - protocol version and capability checks, and the negotiation itself. There are 2 code paths that do not go through fetch_refs_via_pack() that needed to be individually excluded: the bundle transport (excluded through requiring smart_options, which the bundle transport doesn't support) and transport helpers that do not support takeover. If or when we support independent negotiation for protocol v0, we will need to modify these 2 code paths to support it. But for now, report failure if independent negotiation is requested in these cases. Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-01builtin/clone.c: add --reject-shallow optionLibravatar Li Linchao1-0/+1
In some scenarios, users may want more history than the repository offered for cloning, which happens to be a shallow repository, can give them. But because users don't know it is a shallow repository until they download it to local, we may want to refuse to clone this kind of repository, without creating any unnecessary files. The '--depth=x' option cannot be used as a solution; the source may be deep enough to give us 'x' commits when cloned, but the user may later need to deepen the history to arbitrary depth. Teach '--reject-shallow' option to "git clone" to abort as soon as we find out that we are cloning from a shallow repository. Signed-off-by: Li Linchao <lilinchao@oschina.cn> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-03Merge branch 'jt/lazy-fetch'Libravatar Junio C Hamano1-14/+0
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
2020-08-24(various): document from_promisor parameterLibravatar Jonathan Tan1-0/+8
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 <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-18fetch-pack: remove no_dependents codeLibravatar Jonathan Tan1-14/+0
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 <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-06-10fetch-pack: support more than one pack lockfileLibravatar Jonathan Tan1-1/+1
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 <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-03-20fetch_pack(): drop unused parametersLibravatar Jeff King1-2/+1
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 <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-10-04fetch-pack: exclude blobs when lazy-fetching treesLibravatar Jonathan Tan1-0/+7
A partial clone with missing trees can be obtained using "git clone --filter=tree:none <repo>". 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 <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-02Merge branch 'jt/fetch-nego-tip'Libravatar Junio C Hamano1-0/+7
"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
2018-07-03fetch-pack: support negotiation tip whitelistLibravatar Jonathan Tan1-0/+7
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 <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-03fetch-pack: write shallow, then check connectivityLibravatar Jonathan Tan1-0/+15
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 <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-04-24fetch: send server options when using protocol v2Libravatar Brandon Williams1-0/+1
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 <bmwill@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-04-24Merge branch 'bw/protocol-v2' into HEADLibravatar Junio C Hamano1-1/+3
* bw/protocol-v2: (35 commits) remote-curl: don't request v2 when pushing remote-curl: implement stateless-connect command http: eliminate "# service" line when using protocol v2 http: don't always add Git-Protocol header http: allow providing extra headers for http requests remote-curl: store the protocol version the server responded with remote-curl: create copy of the service name pkt-line: add packet_buf_write_len function transport-helper: introduce stateless-connect transport-helper: refactor process_connect_service transport-helper: remove name parameter connect: don't request v2 when pushing connect: refactor git_connect to only get the protocol version once fetch-pack: support shallow requests fetch-pack: perform a fetch using v2 upload-pack: introduce fetch server command push: pass ref prefixes when pushing fetch: pass ref prefixes when fetching ls-remote: pass ref prefixes when requesting a remote's refs transport: convert transport_get_remote_refs to take a list of ref prefixes ...
2018-03-15fetch-pack: perform a fetch using v2Libravatar Brandon Williams1-1/+3
When communicating with a v2 server, perform a fetch by requesting the 'fetch' command. Signed-off-by: Brandon Williams <bmwill@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-12-08fetch-pack, index-pack, transport: partial cloneLibravatar Jeff Hostetler1-0/+2
Signed-off-by: Jeff Hostetler <jeffhost@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-12-05introduce fetch-object: fetch one promisor objectLibravatar Jonathan Tan1-0/+8
Introduce fetch-object, providing the ability to fetch one object from a promisor remote. This uses fetch-pack. To do this, the transport mechanism has been updated with 2 flags, "from-promisor" to indicate that the resulting pack comes from a promisor remote (and thus should be annotated as such by index-pack), and "no-dependents" to indicate that only the objects themselves need to be fetched (but fetching additional objects is nevertheless safe). Whenever "no-dependents" is used, fetch-pack will refrain from using any object flags, because it is most likely invoked as part of a dynamic object fetch by another Git command (which may itself use object flags). An alternative to this is to leave fetch-pack alone, and instead update the allocation of flags so that fetch-pack's flags never overlap with any others, but this will end up shrinking the number of flags available to nearly every other Git command (that is, every Git command that accesses objects), so the approach in this commit was used instead. This will be tested in a subsequent commit. Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-31Rename sha1_array to oid_arrayLibravatar brian m. carlson1-2/+2
Since this structure handles an array of object IDs, rename it to struct oid_array. Also rename the accessor functions and the initialization constant. This commit was produced mechanically by providing non-Documentation files to the following Perl one-liners: perl -pi -E 's/struct sha1_array/struct oid_array/g' perl -pi -E 's/\bsha1_array_/oid_array_/g' perl -pi -E 's/SHA1_ARRAY_INIT/OID_ARRAY_INIT/g' Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-03-02fetch-pack: move code to report unmatched refs to a functionLibravatar Matt McCutchen1-0/+6
Prepare to reuse this code in transport.c for "git fetch". While we're here, internationalize the existing error message. Signed-off-by: Matt McCutchen <matt@mattmccutchen.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-06-13fetch, upload-pack: --deepen=N extends shallow boundary by N commitsLibravatar Nguyễn Thái Ngọc Duy1-0/+1
In git-fetch, --depth argument is always relative with the latest remote refs. This makes it a bit difficult to cover this use case, where the user wants to make the shallow history, say 3 levels deeper. It would work if remote refs have not moved yet, but nobody can guarantee that, especially when that use case is performed a couple months after the last clone or "git fetch --depth". Also, modifying shallow boundary using --depth does not work well with clones created by --since or --not. This patch fixes that. A new argument --deepen=<N> will add <N> more (*) parent commits to the current history regardless of where remote refs are. Have/Want negotiation is still respected. So if remote refs move, the server will send two chunks: one between "have" and "want" and another to extend shallow history. In theory, the client could send no "want"s in order to get the second chunk only. But the protocol does not allow that. Either you send no want lines, which means ls-remote; or you have to send at least one want line that carries deep-relative to the server.. The main work was done by Dongcan Jiang. I fixed it up here and there. And of course all the bugs belong to me. (*) We could even support --deepen=<N> where <N> is negative. In that case we can cut some history from the shallow clone. This operation (and --depth=<shorter depth>) does not require interaction with remote side (and more complicated to implement as a result). Helped-by: Duy Nguyen <pclouds@gmail.com> Helped-by: Eric Sunshine <sunshine@sunshineco.com> Helped-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Dongcan Jiang <dongcan.jiang@gmail.com> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-06-13fetch: define shallow boundary with --shallow-excludeLibravatar Nguyễn Thái Ngọc Duy1-0/+1
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-06-13fetch: define shallow boundary with --shallow-sinceLibravatar Nguyễn Thái Ngọc Duy1-0/+1
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-06-13fetch-pack: use a separate flag for fetch in deepening modeLibravatar Nguyễn Thái Ngọc Duy1-0/+1
The shallow repo could be deepened or shortened when then user gives --depth. But in future that won't be the only way to deepen/shorten a repo. Stop relying on args->depth in this mode. Future deepening methods can simply set this flag on instead of updating all these if expressions. The new name "deepen" was chosen after the command to define shallow boundary in pack protocol. New commands also follow this tradition. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2014-01-17Merge branch 'nd/shallow-clone'Libravatar Junio C Hamano1-13/+18
Fetching from a shallow-cloned repository used to be forbidden, primarily because the codepaths involved were not carefully vetted and we did not bother supporting such usage. This attempts to allow object transfer out of a shallow-cloned repository in a controlled way (i.e. the receiver become a shallow repository with truncated history). * nd/shallow-clone: (31 commits) t5537: fix incorrect expectation in test case 10 shallow: remove unused code send-pack.c: mark a file-local function static git-clone.txt: remove shallow clone limitations prune: clean .git/shallow after pruning objects clone: use git protocol for cloning shallow repo locally send-pack: support pushing from a shallow clone via http receive-pack: support pushing to a shallow clone via http smart-http: support shallow fetch/clone remote-curl: pass ref SHA-1 to fetch-pack as well send-pack: support pushing to a shallow clone receive-pack: allow pushes that update .git/shallow connected.c: add new variant that runs with --shallow-file add GIT_SHALLOW_FILE to propagate --shallow-file to subprocesses receive/send-pack: support pushing from a shallow clone receive-pack: reorder some code in unpack() fetch: add --update-shallow to accept refs that update .git/shallow upload-pack: make sure deepening preserves shallow roots fetch: support fetching from a shallow repository clone: support remote shallow repository ...
2013-12-10fetch: add --update-shallow to accept refs that update .git/shallowLibravatar Nguyễn Thái Ngọc Duy1-0/+1
The same steps are done as in when --update-shallow is not given. The only difference is we now add all shallow commits in "ours" and "theirs" to .git/shallow (aka "step 8"). Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-12-10clone: support remote shallow repositoryLibravatar Nguyễn Thái Ngọc Duy1-0/+4
Cloning from a shallow repository does not follow the "8 steps for new .git/shallow" because if it does we need to get through step 6 for all refs. That means commit walking down to the bottom. Instead the rule to create .git/shallow is simpler and, more importantly, cheap: if a shallow commit is found in the pack, it's probably used (i.e. reachable from some refs), so we add it. Others are dropped. One may notice this method seems flawed by the word "probably". A shallow commit may not be reachable from any refs at all if it's attached to an object island (a group of objects that are not reachable by any refs). If that object island is not complete, a new fetch request may send more objects to connect it to some ref. At that time, because we incorrectly installed the shallow commit in this island, the user will not see anything after that commit (fsck is still ok). This is not desired. Given that object islands are rare (C Git never sends such islands for security reasons) and do not really harm the repository integrity, a tradeoff is made to surprise the user occasionally but work faster everyday. A new option --strict could be added later that follows exactly the 8 steps. "git prune" can also learn to remove dangling objects _and_ the shallow commits that are attached to them from .git/shallow. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-12-10fetch-pack.h: one statement per bitfield declarationLibravatar Nguyễn Thái Ngọc Duy1-12/+12
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-12-09git fetch-pack: add --diag-urlLibravatar Torsten Bögershausen1-0/+1
The main purpose is to trace the URL parser called by git_connect() in connect.c The main features of the parser can be listed as this: - parse out host and path for URLs with a scheme (git:// file:// ssh://) - parse host names embedded by [] correctly - extract the port number, if present - separate URLs like "file" (which are local) from URLs like "host:repo" which should use ssh Add the new parameter "--diag-url" to "git fetch-pack", which prints the value for protocol, host and path to stderr and exits. Signed-off-by: Torsten Bögershausen <tboegi@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-07-08cache.h: move remote/connect API out of itLibravatar Junio C Hamano1-0/+1
The definition of "struct ref" in "cache.h", a header file so central to the system, always confused me. This structure is not about the local ref used by sha1-name API to name local objects. It is what refspecs are expanded into, after finding out what refs the other side has, to define what refs are updated after object transfer succeeds to what values. It belongs to "remote.h" together with "struct refspec". While we are at it, also move the types and functions related to the Git transport connection to a new header file connect.h Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-05-28clone: open a shortcut for connectivity checkLibravatar Nguyễn Thái Ngọc Duy1-1/+3
In order to make sure the cloned repository is good, we run "rev-list --objects --not --all $new_refs" on the repository. This is expensive on large repositories. This patch attempts to mitigate the impact in this special case. In the "good" clone case, we only have one pack. If all of the following are met, we can be sure that all objects reachable from the new refs exist, which is the intention of running "rev-list ...": - all refs point to an object in the pack - there are no dangling pointers in any object in the pack - no objects in the pack point to objects outside the pack The second and third checks can be done with the help of index-pack as a slight variation of --strict check (which introduces a new condition for the shortcut: pack transfer must be used and the number of objects large enough to call index-pack). The first is checked in check_everything_connected after we get an "ok" from index-pack. "index-pack + new checks" is still faster than the current "index-pack + rev-list", which is the whole point of this patch. If any of the conditions fail, we fall back to the good old but expensive "rev-list ..". In that case it's even more expensive because we have to pay for the new checks in index-pack. But that should only happen when the other side is either buggy or malicious. Cloning linux-2.6 over file:// before after real 3m25.693s 2m53.050s user 5m2.037s 4m42.396s sys 0m13.750s 0m16.574s A more realistic test with ssh:// over wireless before after real 11m26.629s 10m4.213s user 5m43.196s 5m19.444s sys 0m35.812s 0m37.630s This shortcut is not applied to shallow clones, partly because shallow clones should have no more objects than a usual fetch and the cost of rev-list is acceptable, partly to avoid dealing with corner cases when grafting is involved. This shortcut does not apply to unpack-objects code path either because the number of objects must be small in order to trigger that code path. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2013-02-07fetch: use struct ref to represent refs to be fetchedLibravatar Junio C Hamano1-6/+5
Even though "git fetch" has full infrastructure to parse refspecs to be fetched and match them against the list of refs to come up with the final list of refs to be fetched, the list of refs that are requested to be fetched were internally converted to a plain list of strings at the transport layer and then passed to the underlying fetch-pack driver. Stop this conversion and instead pass around an array of refs. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-09-12filter_refs(): delete matched refs from sought listLibravatar Michael Haggerty1-0/+7
Remove any references that are available from the remote from the sought list (rather than overwriting their names with NUL characters, as previously). Mark matching entries by writing a non-NULL pointer to string_list_item::util during the iteration, then use filter_string_list() later to filter out the entries that have been marked. Document this aspect of fetch_pack() in a comment in the header file. (More documentation is obviously still needed.) Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-09-12Change fetch_pack() and friends to take string_list argumentsLibravatar Michael Haggerty1-2/+3
Instead of juggling <nr_heads,heads> (sometimes called <nr_match,match>), pass around the list of references to be sought in a single string_list variable called "sought". Future commits will make more use of string_list functionality. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-09-12fetch_pack(): reindent function decl and defnLibravatar Michael Haggerty1-6/+6
Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2012-04-02fetch-pack: new --stdin option to read refs from stdinLibravatar Ivan Todoroski1-0/+1
If a remote repo has too many tags (or branches), cloning it over the smart HTTP transport can fail because remote-curl.c puts all the refs from the remote repo on the fetch-pack command line. This can make the command line longer than the global OS command line limit, causing fetch-pack to fail. This is especially a problem on Windows where the command line limit is orders of magnitude shorter than Linux. There are already real repos out there that msysGit cannot clone over smart HTTP due to this problem. Here is an easy way to trigger this problem: git init too-many-refs cd too-many-refs echo bla > bla.txt git add . git commit -m test sha=$(git rev-parse HEAD) tag=$(perl -e 'print "bla" x 30') for i in `seq 50000`; do echo $sha refs/tags/$tag-$i >> .git/packed-refs done Then share this repo over the smart HTTP protocol and try cloning it: $ git clone http://localhost/.../too-many-refs/.git Cloning into 'too-many-refs'... fatal: cannot exec 'fetch-pack': Argument list too long 50k tags is obviously an absurd number, but it is required to demonstrate the problem on Linux because it has a much more generous command line limit. On Windows the clone fails with as little as 500 tags in the above loop, which is getting uncomfortably close to the number of tags you might see in real long lived repos. This is not just theoretical, msysGit is already failing to clone our company repo due to this. It's a large repo converted from CVS, nearly 10 years of history. Four possible solutions were discussed on the Git mailing list (in no particular order): 1) Call fetch-pack multiple times with smaller batches of refs. This was dismissed as inefficient and inelegant. 2) Add option --refs-fd=$n to pass a an fd from where to read the refs. This was rejected because inheriting descriptors other than stdin/stdout/stderr through exec() is apparently problematic on Windows, plus it would require changes to the run-command API to open extra pipes. 3) Add option --refs-from=$tmpfile to pass the refs using a temp file. This was not favored because of the temp file requirement. 4) Add option --stdin to pass the refs on stdin, one per line. In the end this option was chosen as the most efficient and most desirable from scripting perspective. There was however a small complication when using stdin to pass refs to fetch-pack. The --stateless-rpc option to fetch-pack also uses stdin for communication with the remote server. If we are going to sneak refs on stdin line by line, it would have to be done very carefully in the presence of --stateless-rpc, because when reading refs line by line we might read ahead too much data into our buffer and eat some of the remote protocol data which is also coming on stdin. One way to solve this would be to refactor get_remote_heads() in fetch-pack.c to accept a residual buffer from our stdin line parsing above, but this function is used in several places so other callers would be burdened by this residual buffer interface even when most of them don't need it. In the end we settled on the following solution: If --stdin is specified without --stateless-rpc, fetch-pack would read the refs from stdin one per line, in a script friendly format. However if --stdin is specified together with --stateless-rpc, fetch-pack would read the refs from stdin in packetized format (pkt-line) with a flush packet terminating the list of refs. This way we can read the exact number of bytes that we need from stdin, and then get_remote_heads() can continue reading from the same fd without losing a single byte of remote protocol data. This way the --stdin option only loses generality and scriptability when used together with --stateless-rpc, which is not easily scriptable anyway because it also uses pkt-line when talking to the remote server. Signed-off-by: Ivan Todoroski <grnch@gmx.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2011-03-16standardize brace placement in struct definitionsLibravatar Jonathan Nieder1-2/+1
In a struct definitions, unlike functions, the prevailing style is for the opening brace to go on the same line as the struct name, like so: struct foo { int bar; char *baz; }; Indeed, grepping for 'struct [a-z_]* {$' yields about 5 times as many matches as 'struct [a-z_]*$'. Linus sayeth: Heretic people all over the world have claimed that this inconsistency is ... well ... inconsistent, but all right-thinking people know that (a) K&R are _right_ and (b) K&R are right. Signed-off-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2009-11-04Smart fetch over HTTP: client sideLibravatar Shawn O. Pearce1-1/+2
The git-remote-curl backend detects if the remote server supports the git-upload-pack service, and if so, runs git-fetch-pack locally in a pipe to generate the want/have commands. The advertisements from the server that were obtained during the discovery are passed into git-fetch-pack before the POST request starts, permitting server capability discovery and enablement. Common objects that are discovered are appended onto the request as have lines and are sent again on the next request. This allows the remote side to reinitialize its in-memory list of common objects during the next request. Because all requests are relatively short, below git-remote-curl's 1 MiB buffer limit, requests will use the standard Content-Length header and be valid HTTP/1.0 POST requests. This makes the fetch client more tolerant of proxy servers which don't support HTTP/1.1 or the chunked transfer encoding. Signed-off-by: Shawn O. Pearce <spearce@spearce.org> CC: Daniel Barkalow <barkalow@iabervon.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-03-04Teach fetch-pack/upload-pack about --include-tagLibravatar Shawn O. Pearce1-1/+2
The new protocol extension "include-tag" allows the client side of the connection (fetch-pack) to request that the server side of the native git protocol (upload-pack / pack-objects) use --include-tag as it prepares the packfile, thus ensuring that an annotated tag object will be included in the resulting packfile if the object it refers to was also included into the packfile. Signed-off-by: Shawn O. Pearce <spearce@spearce.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2008-02-05Reduce the number of connects when fetchingLibravatar Daniel Barkalow1-0/+2
This shares the connection between getting the remote ref list and getting objects in the first batch. (A second connection is still used to follow tags). When we do not fetch objects (i.e. either ls-remote disconnects after getting list of refs, or we decide we are already up-to-date), we clean up the connection properly; otherwise the connection is left open in need of cleaning up to avoid getting an error message from the remote end when ssh is used. Signed-off-by: Daniel Barkalow <barkalow@iabervon.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-09-19Always obtain fetch-pack arguments from struct fetch_pack_argsLibravatar Shawn O. Pearce1-3/+6
Copying the arguments from a fetch_pack_args into static globals within the builtin-fetch-pack module is error-prone and may lead rise to cases where arguments supplied via the struct from the new fetch_pack() API may not be honored by the implementation. Here we reorganize all of the static globals into a single static struct fetch_pack_args instance and use memcpy() to move the data from the caller supplied structure into the globals before we execute our pack fetching implementation. This strategy is more robust to additions and deletions of properties. As keep_pack is a single bit we have also introduced lock_pack to mean not only download and store the packfile via index-pack but also to lock it against repacking by creating a .keep file when the packfile itself is stored. The caller must remove the .keep file when it is safe to do so. Signed-off-by: Shawn O. Pearce <spearce@spearce.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-09-19Use 'unsigned:1' when we mean boolean optionsLibravatar Shawn O. Pearce1-6/+6
These options are all strictly boolean (true/false). Its easier to document this implicitly by making their storage type a single bit. There is no compelling memory space reduction reason for this change, it just makes the structure definition slightly more readable. Signed-off-by: Shawn O. Pearce <spearce@spearce.org>
2007-09-19Remove pack.keep after ref updates in git-fetchLibravatar Shawn O. Pearce1-1/+1
If we are using a native packfile to perform a git-fetch invocation and the received packfile contained more than the configured limits of fetch.unpackLimit/transfer.unpackLimit then index-pack will output a single line saying "keep\t$sha1\n" to stdout. This line needs to be captured and retained so we can delete the corresponding .keep file ("$GIT_DIR/objects/pack/pack-$sha1.keep") once all refs have been safely updated. This trick has long been in use with git-fetch.sh and its lower level helper git-fetch--tool as a way to allow index-pack to save the new packfile before the refs have been updated and yet avoid a race with any concurrently running git-repack process. It was unfortunately lost when git-fetch.sh was converted to pure C and fetch--tool was no longer being invoked. Signed-off-by: Shawn O. Pearce <spearce@spearce.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-09-19Make fetch-pack a builtin with an internal APILibravatar Daniel Barkalow1-0/+21
Signed-off-by: Daniel Barkalow <barkalow@iabervon.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>