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NAME

       gitnamespaces - Git namespaces

SYNOPSIS

       GIT_NAMESPACE=<namespace> git upload-pack
       GIT_NAMESPACE=<namespace> git receive-pack

DESCRIPTION

       Git supports dividing the refs of a single repository into multiple
       namespaces, each of which has its own branches, tags, and HEAD. Git can
       expose each namespace as an independent repository to pull from and
       push to, while sharing the object store, and exposing all the refs to
       operations such as git-gc(1).

       Storing multiple repositories as namespaces of a single repository
       avoids storing duplicate copies of the same objects, such as when
       storing multiple branches of the same source. The alternates mechanism
       provides similar support for avoiding duplicates, but alternates do not
       prevent duplication between new objects added to the repositories
       without ongoing maintenance, while namespaces do.

       To specify a namespace, set the GIT_NAMESPACE environment variable to
       the namespace. For each ref namespace, git stores the corresponding
       refs in a directory under refs/namespaces/. For example,
       GIT_NAMESPACE=foo will store refs under refs/namespaces/foo/. You can
       also specify namespaces via the --namespace option to git(1).

       Note that namespaces which include a / will expand to a hierarchy of
       namespaces; for example, GIT_NAMESPACE=foo/bar will store refs under
       refs/namespaces/foo/refs/namespaces/bar/. This makes paths in
       GIT_NAMESPACE behave hierarchically, so that cloning with
       GIT_NAMESPACE=foo/bar produces the same result as cloning with
       GIT_NAMESPACE=foo and cloning from that repo with GIT_NAMESPACE=bar. It
       also avoids ambiguity with strange namespace paths such as
       foo/refs/heads/, which could otherwise generate directory/file
       conflicts within the refs directory.

       git-upload-pack(1) and git-receive-pack(1) rewrite the names of refs as
       specified by GIT_NAMESPACE. git-upload-pack and git-receive-pack will
       ignore all references outside the specified namespace.

       The smart HTTP server, git-http-backend(1), will pass GIT_NAMESPACE
       through to the backend programs; see git-http-backend(1) for sample
       configuration to expose repository namespaces as repositories.

       For a simple local test, you can use git-remote-ext(1):

           git clone ext::'git --namespace=foo %s /tmp/prefixed.git'

SECURITY

       Anyone with access to any namespace within a repository can potentially
       access objects from any other namespace stored in the same repository.
       You can't directly say "give me object ABCD" if you don't have a ref to
       it, but you can do some other sneaky things like:

        1. Claiming to push ABCD, at which point the server will optimize out
           the need for you to actually send it. Now you have a ref to ABCD
           and can fetch it (claiming not to have it, of course).

        2. Requesting other refs, claiming that you have ABCD, at which point
           the server may generate deltas against ABCD.

       None of this causes a problem if you only host public repositories, or
       if everyone who may read one namespace may also read everything in
       every other namespace (for instance, if everyone in an organization has
       read permission to every repository).