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Diffstat (limited to 'Documentation/gitsubmodules.txt')
| -rw-r--r-- | Documentation/gitsubmodules.txt | 100 |
1 files changed, 79 insertions, 21 deletions
diff --git a/Documentation/gitsubmodules.txt b/Documentation/gitsubmodules.txt index 030c974c25..3b9faabdbb 100644 --- a/Documentation/gitsubmodules.txt +++ b/Documentation/gitsubmodules.txt @@ -36,8 +36,8 @@ The `gitlink` entry contains the object name of the commit that the superproject expects the submodule's working directory to be at. The section `submodule.foo.*` in the `.gitmodules` file gives additional -hints to Gits porcelain layer such as where to obtain the submodule via -the `submodule.foo.url` setting. +hints to Git's porcelain layer. For example, the `submodule.foo.url` +setting specifies where to obtain the submodule. Submodules can be used for at least two different use cases: @@ -51,18 +51,21 @@ Submodules can be used for at least two different use cases: 2. Splitting a (logically single) project into multiple repositories and tying them back together. This can be used to - overcome current limitations of Gits implementation to have + overcome current limitations of Git's implementation to have finer grained access: - * Size of the git repository: + * Size of the Git repository: In its current form Git scales up poorly for large repositories containing content that is not compressed by delta computation between trees. - However you can also use submodules to e.g. hold large binary assets - and these repositories are then shallowly cloned such that you do not + For example, you can use submodules to hold large binary assets + and these repositories can be shallowly cloned such that you do not have a large history locally. * Transfer size: In its current form Git requires the whole working tree present. It does not allow partial trees to be transferred in fetch or clone. + If the project you work on consists of multiple repositories tied + together as submodules in a superproject, you can avoid fetching the + working trees of the repositories you are not interested in. * Access control: By restricting user access to submodules, this can be used to implement read/write policies for different users. @@ -73,9 +76,10 @@ The configuration of submodules Submodule operations can be configured using the following mechanisms (from highest to lowest precedence): - * The command line for those commands that support taking submodule specs. - Most commands have a boolean flag '--recurse-submodules' whether to - recurse into submodules. Examples are `ls-files` or `checkout`. + * The command line for those commands that support taking submodules + as part of their pathspecs. Most commands have a boolean flag + `--recurse-submodules` which specify whether to recurse into submodules. + Examples are `grep` and `checkout`. Some commands take enums, such as `fetch` and `push`, where you can specify how submodules are affected. @@ -87,8 +91,8 @@ Submodule operations can be configured using the following mechanisms For example an effect from the submodule's `.gitignore` file would be observed when you run `git status --ignore-submodules=none` in the superproject. This collects information from the submodule's working -directory by running `status` in the submodule, which does pay attention -to its `.gitignore` file. +directory by running `status` in the submodule while paying attention +to the `.gitignore` file of the submodule. + The submodule's `$GIT_DIR/config` file would come into play when running `git push --recurse-submodules=check` in the superproject, as this would @@ -97,20 +101,20 @@ remotes are configured in the submodule as usual in the `$GIT_DIR/config` file. * The configuration file `$GIT_DIR/config` in the superproject. - Typical configuration at this place is controlling if a submodule - is recursed into at all via the `active` flag for example. + Git only recurses into active submodules (see "ACTIVE SUBMODULES" + section below). + If the submodule is not yet initialized, then the configuration -inside the submodule does not exist yet, so configuration where to +inside the submodule does not exist yet, so where to obtain the submodule from is configured here for example. - * the `.gitmodules` file inside the superproject. Additionally to the - required mapping between submodule's name and path, a project usually + * The `.gitmodules` file inside the superproject. A project usually uses this file to suggest defaults for the upstream collection - of repositories. + of repositories for the mapping that is required between a + submodule's name and its path. + -This file mainly serves as the mapping between name and path in -the superproject, such that the submodule's git directory can be +This file mainly serves as the mapping between the name and path of submodules +in the superproject, such that the submodule's Git directory can be located. + If the submodule has never been initialized, this is the only place @@ -137,8 +141,8 @@ directory is automatically moved to `$GIT_DIR/modules/<name>/` of the superproject. * Deinitialized submodule: A `gitlink`, and a `.gitmodules` entry, -but no submodule working directory. The submodule's git directory -may be there as after deinitializing the git directory is kept around. +but no submodule working directory. The submodule's Git directory +may be there as after deinitializing the Git directory is kept around. The directory which is supposed to be the working directory is empty instead. + A submodule can be deinitialized by running `git submodule deinit`. @@ -160,6 +164,60 @@ from another repository. To completely remove a submodule, manually delete `$GIT_DIR/modules/<name>/`. +ACTIVE SUBMODULES +----------------- + +A submodule is considered active, + + (a) if `submodule.<name>.active` is set to `true` + or + (b) if the submodule's path matches the pathspec in `submodule.active` + or + (c) if `submodule.<name>.url` is set. + +and these are evaluated in this order. + +For example: + + [submodule "foo"] + active = false + url = https://example.org/foo + [submodule "bar"] + active = true + url = https://example.org/bar + [submodule "baz"] + url = https://example.org/baz + +In the above config only the submodule 'bar' and 'baz' are active, +'bar' due to (a) and 'baz' due to (c). 'foo' is inactive because +(a) takes precedence over (c) + +Note that (c) is a historical artefact and will be ignored if the +(a) and (b) specify that the submodule is not active. In other words, +if we have an `submodule.<name>.active` set to `false` or if the +submodule's path is excluded in the pathspec in `submodule.active`, the +url doesn't matter whether it is present or not. This is illustrated in +the example that follows. + + [submodule "foo"] + active = true + url = https://example.org/foo + [submodule "bar"] + url = https://example.org/bar + [submodule "baz"] + url = https://example.org/baz + [submodule "bob"] + ignore = true + [submodule] + active = b* + active = :(exclude) baz + +In here all submodules except 'baz' (foo, bar, bob) are active. +'foo' due to its own active flag and all the others due to the +submodule active pathspec, which specifies that any submodule +starting with 'b' except 'baz' are also active, regardless of the +presence of the .url field. + Workflow for a third party library ---------------------------------- |