git/Documentation/config/fetch.txt
Derrick Stolee c429bed102 bundle-uri: store fetch.bundleCreationToken
When a bundle list specifies the "creationToken" heuristic, the Git
client downloads the list and then starts downloading bundles in
descending creationToken order. This process stops as soon as all
downloaded bundles can be applied to the repository (because all
required commits are present in the repository or in the downloaded
bundles).

When checking the same bundle list twice, this strategy requires
downloading the bundle with the maximum creationToken again, which is
wasteful. The creationToken heuristic promises that the client will not
have a use for that bundle if its creationToken value is at most the
previous creationToken value.

To prevent these wasteful downloads, create a fetch.bundleCreationToken
config setting that the Git client sets after downloading bundles. This
value allows skipping that maximum bundle download when this config
value is the same value (or larger).

To test that this works correctly, we can insert some "duplicate"
fetches into existing tests and demonstrate that only the bundle list is
downloaded.

The previous logic for downloading bundles by creationToken worked even
if the bundle list was empty, but now we have logic that depends on the
first entry of the list. Terminate early in the (non-sensical) case of
an empty bundle list.

Signed-off-by: Derrick Stolee <derrickstolee@github.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2023-01-31 08:57:48 -08:00

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fetch.recurseSubmodules::
This option controls whether `git fetch` (and the underlying fetch
in `git pull`) will recursively fetch into populated submodules.
This option can be set either to a boolean value or to 'on-demand'.
Setting it to a boolean changes the behavior of fetch and pull to
recurse unconditionally into submodules when set to true or to not
recurse at all when set to false. When set to 'on-demand', fetch and
pull will only recurse into a populated submodule when its
superproject retrieves a commit that updates the submodule's
reference.
Defaults to 'on-demand', or to the value of 'submodule.recurse' if set.
fetch.fsckObjects::
If it is set to true, git-fetch-pack will check all fetched
objects. See `transfer.fsckObjects` for what's
checked. Defaults to false. If not set, the value of
`transfer.fsckObjects` is used instead.
fetch.fsck.<msg-id>::
Acts like `fsck.<msg-id>`, but is used by
linkgit:git-fetch-pack[1] instead of linkgit:git-fsck[1]. See
the `fsck.<msg-id>` documentation for details.
fetch.fsck.skipList::
Acts like `fsck.skipList`, but is used by
linkgit:git-fetch-pack[1] instead of linkgit:git-fsck[1]. See
the `fsck.skipList` documentation for details.
fetch.unpackLimit::
If the number of objects fetched over the Git native
transfer is below this
limit, then the objects will be unpacked into loose object
files. However if the number of received objects equals or
exceeds this limit then the received pack will be stored as
a pack, after adding any missing delta bases. Storing the
pack from a push can make the push operation complete faster,
especially on slow filesystems. If not set, the value of
`transfer.unpackLimit` is used instead.
fetch.prune::
If true, fetch will automatically behave as if the `--prune`
option was given on the command line. See also `remote.<name>.prune`
and the PRUNING section of linkgit:git-fetch[1].
fetch.pruneTags::
If true, fetch will automatically behave as if the
`refs/tags/*:refs/tags/*` refspec was provided when pruning,
if not set already. This allows for setting both this option
and `fetch.prune` to maintain a 1=1 mapping to upstream
refs. See also `remote.<name>.pruneTags` and the PRUNING
section of linkgit:git-fetch[1].
fetch.output::
Control how ref update status is printed. Valid values are
`full` and `compact`. Default value is `full`. See section
OUTPUT in linkgit:git-fetch[1] for detail.
fetch.negotiationAlgorithm::
Control how information about the commits in the local repository
is sent when negotiating the contents of the packfile to be sent by
the server. Set to "consecutive" to use an algorithm that walks
over consecutive commits checking each one. Set to "skipping" to
use an algorithm that skips commits in an effort to converge
faster, but may result in a larger-than-necessary packfile; or set
to "noop" to not send any information at all, which will almost
certainly result in a larger-than-necessary packfile, but will skip
the negotiation step. Set to "default" to override settings made
previously and use the default behaviour. The default is normally
"consecutive", but if `feature.experimental` is true, then the
default is "skipping". Unknown values will cause 'git fetch' to
error out.
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See also the `--negotiate-only` and `--negotiation-tip` options to
linkgit:git-fetch[1].
fetch.showForcedUpdates::
Set to false to enable `--no-show-forced-updates` in
linkgit:git-fetch[1] and linkgit:git-pull[1] commands.
Defaults to true.
fetch.parallel::
Specifies the maximal number of fetch operations to be run in parallel
at a time (submodules, or remotes when the `--multiple` option of
linkgit:git-fetch[1] is in effect).
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A value of 0 will give some reasonable default. If unset, it defaults to 1.
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For submodules, this setting can be overridden using the `submodule.fetchJobs`
config setting.
fetch.writeCommitGraph::
Set to true to write a commit-graph after every `git fetch` command
that downloads a pack-file from a remote. Using the `--split` option,
most executions will create a very small commit-graph file on top of
the existing commit-graph file(s). Occasionally, these files will
merge and the write may take longer. Having an updated commit-graph
file helps performance of many Git commands, including `git merge-base`,
`git push -f`, and `git log --graph`. Defaults to false.
fetch.bundleURI::
This value stores a URI for downloading Git object data from a bundle
URI before performing an incremental fetch from the origin Git server.
This is similar to how the `--bundle-uri` option behaves in
linkgit:git-clone[1]. `git clone --bundle-uri` will set the
`fetch.bundleURI` value if the supplied bundle URI contains a bundle
list that is organized for incremental fetches.
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If you modify this value and your repository has a `fetch.bundleCreationToken`
value, then remove that `fetch.bundleCreationToken` value before fetching from
the new bundle URI.
fetch.bundleCreationToken::
When using `fetch.bundleURI` to fetch incrementally from a bundle
list that uses the "creationToken" heuristic, this config value
stores the maximum `creationToken` value of the downloaded bundles.
This value is used to prevent downloading bundles in the future
if the advertised `creationToken` is not strictly larger than this
value.
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The creation token values are chosen by the provider serving the specific
bundle URI. If you modify the URI at `fetch.bundleURI`, then be sure to
remove the value for the `fetch.bundleCreationToken` value before fetching.