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The current `update` command incorporates the superproject's gitlinked
SHA-1 ($sha1) into the submodule HEAD ($subsha1). Depending on the
options you use, it may checkout $sha1, rebase the $subsha1 onto
$sha1, or merge $sha1 into $subsha1. This helps you keep up with
changes in the upstream superproject.
However, it's also useful to stay up to date with changes in the
upstream subproject. Previous workflows for incorporating such
changes include the ungainly:
$ git submodule foreach 'git checkout $(git config --file $toplevel/.gitmodules submodule.$name.branch) && git pull'
With this patch, all of the useful functionality for incorporating
superproject changes can be reused to incorporate upstream subproject
updates. When you specify --remote, the target $sha1 is replaced with
a $sha1 of the submodule's origin/master tracking branch. If you want
to merge a different tracking branch, you can configure the
`submodule.<name>.branch` option in `.gitmodules`. You can override
the `.gitmodules` configuration setting for a particular superproject
by configuring the option in that superproject's default configuration
(using the usual configuration hierarchy, e.g. `.git/config`,
`~/.gitconfig`, etc.).
Previous use of submodule.<name>.branch
=======================================
Because we're adding a new configuration option, it's a good idea to
check if anyone else is already using the option. The foreach-pull
example above was described by Ævar in
commit f030c96d86
Author: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Date: Fri May 21 16:10:10 2010 +0000
git-submodule foreach: Add $toplevel variable
Gerrit uses the same interpretation for the setting, but because
Gerrit has direct access to the subproject repositories, it updates
the superproject repositories automatically when a subproject changes.
Gerrit also accepts the special value '.', which it expands into the
superproject's branch name.
Although the --remote functionality is using `submodule.<name>.branch`
slightly differently, the effect is the same. The foreach-pull
example uses the option to record the name of the local branch to
checkout before pulls. The tracking branch to be pulled is recorded
in `.git/modules/<name>/config`, which was initialized by the module
clone during `submodule add` or `submodule init`. Because the branch
name stored in `submodule.<name>.branch` was likely the same as the
branch name used during the initial `submodule add`, the same branch
will be pulled in each workflow.
Implementation details
======================
In order to ensure a current tracking branch state, `update --remote`
fetches the submodule's remote repository before calculating the
SHA-1. However, I didn't change the logic guarding the existing fetch:
if test -z "$nofetch"
then
# Run fetch only if $sha1 isn't present or it
# is not reachable from a ref.
(clear_local_git_env; cd "$path" &&
( (rev=$(git rev-list -n 1 $sha1 --not --all 2>/dev/null) &&
test -z "$rev") || git-fetch)) ||
die "$(eval_gettext "Unable to fetch in submodule path '\$path'")"
fi
There will not be a double-fetch, because the new $sha1 determined
after the `--remote` triggered fetch should always exist in the
repository. If it doesn't, it's because some racy process removed it
from the submodule's repository and we *should* be re-fetching.
Signed-off-by: W. Trevor King <wking@tremily.us>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
106 lines
3.8 KiB
Plaintext
106 lines
3.8 KiB
Plaintext
gitmodules(5)
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=============
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NAME
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----
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gitmodules - defining submodule properties
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SYNOPSIS
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--------
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$GIT_WORK_DIR/.gitmodules
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DESCRIPTION
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-----------
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The `.gitmodules` file, located in the top-level directory of a git
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working tree, is a text file with a syntax matching the requirements
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of linkgit:git-config[1].
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The file contains one subsection per submodule, and the subsection value
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is the name of the submodule. The name is set to the path where the
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submodule has been added unless it was customized with the '--name'
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option of 'git submodule add'. Each submodule section also contains the
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following required keys:
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submodule.<name>.path::
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Defines the path, relative to the top-level directory of the git
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working tree, where the submodule is expected to be checked out.
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The path name must not end with a `/`. All submodule paths must
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be unique within the .gitmodules file.
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submodule.<name>.url::
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Defines a URL from which the submodule repository can be cloned.
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This may be either an absolute URL ready to be passed to
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linkgit:git-clone[1] or (if it begins with ./ or ../) a location
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relative to the superproject's origin repository.
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submodule.<name>.update::
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Defines what to do when the submodule is updated by the superproject.
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If 'checkout' (the default), the new commit specified in the
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superproject will be checked out in the submodule on a detached HEAD.
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If 'rebase', the current branch of the submodule will be rebased onto
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the commit specified in the superproject. If 'merge', the commit
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specified in the superproject will be merged into the current branch
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in the submodule.
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If 'none', the submodule with name `$name` will not be updated
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by default.
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This config option is overridden if 'git submodule update' is given
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the '--merge', '--rebase' or '--checkout' options.
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submodule.<name>.branch::
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A remote branch name for tracking updates in the upstream submodule.
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If the option is not specified, it defaults to 'master'. See the
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`--remote` documentation in linkgit:git-submodule[1] for details.
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submodule.<name>.fetchRecurseSubmodules::
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This option can be used to control recursive fetching of this
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submodule. If this option is also present in the submodules entry in
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.git/config of the superproject, the setting there will override the
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one found in .gitmodules.
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Both settings can be overridden on the command line by using the
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"--[no-]recurse-submodules" option to "git fetch" and "git pull".
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submodule.<name>.ignore::
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Defines under what circumstances "git status" and the diff family show
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a submodule as modified. When set to "all", it will never be considered
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modified, "dirty" will ignore all changes to the submodules work tree and
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takes only differences between the HEAD of the submodule and the commit
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recorded in the superproject into account. "untracked" will additionally
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let submodules with modified tracked files in their work tree show up.
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Using "none" (the default when this option is not set) also shows
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submodules that have untracked files in their work tree as changed.
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If this option is also present in the submodules entry in .git/config of
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the superproject, the setting there will override the one found in
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.gitmodules.
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Both settings can be overridden on the command line by using the
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"--ignore-submodule" option.
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EXAMPLES
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--------
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Consider the following .gitmodules file:
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[submodule "libfoo"]
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path = include/foo
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url = git://foo.com/git/lib.git
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[submodule "libbar"]
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path = include/bar
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url = git://bar.com/git/lib.git
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This defines two submodules, `libfoo` and `libbar`. These are expected to
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be checked out in the paths 'include/foo' and 'include/bar', and for both
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submodules a URL is specified which can be used for cloning the submodules.
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SEE ALSO
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--------
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linkgit:git-submodule[1] linkgit:git-config[1]
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GIT
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---
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Part of the linkgit:git[1] suite
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