1gitnamespaces(7) 2================ 3 4NAME 5---- 6gitnamespaces - Git namespaces 7 8SYNOPSIS 9-------- 10[verse] 11GIT_NAMESPACE=<namespace> 'git upload-pack' 12GIT_NAMESPACE=<namespace> 'git receive-pack' 13 14 15DESCRIPTION 16----------- 17 18Git supports dividing the refs of a single repository into multiple 19namespaces, each of which has its own branches, tags, and HEAD. Git can 20expose each namespace as an independent repository to pull from and push 21to, while sharing the object store, and exposing all the refs to 22operations such as linkgit:git-gc[1]. 23 24Storing multiple repositories as namespaces of a single repository 25avoids storing duplicate copies of the same objects, such as when 26storing multiple branches of the same source. The alternates mechanism 27provides similar support for avoiding duplicates, but alternates do not 28prevent duplication between new objects added to the repositories 29without ongoing maintenance, while namespaces do. 30 31To specify a namespace, set the `GIT_NAMESPACE` environment variable to 32the namespace. For each ref namespace, git stores the corresponding 33refs in a directory under `refs/namespaces/`. For example, 34`GIT_NAMESPACE=foo` will store refs under `refs/namespaces/foo/`. You 35can also specify namespaces via the `--namespace` option to 36linkgit:git[1]. 37 38Note that namespaces which include a `/` will expand to a hierarchy of 39namespaces; for example, `GIT_NAMESPACE=foo/bar` will store refs under 40`refs/namespaces/foo/refs/namespaces/bar/`. This makes paths in 41`GIT_NAMESPACE` behave hierarchically, so that cloning with 42`GIT_NAMESPACE=foo/bar` produces the same result as cloning with 43`GIT_NAMESPACE=foo` and cloning from that repo with `GIT_NAMESPACE=bar`. It 44also avoids ambiguity with strange namespace paths such as `foo/refs/heads/`, 45which could otherwise generate directory/file conflicts within the `refs` 46directory. 47 48linkgit:git-upload-pack[1] and linkgit:git-receive-pack[1] rewrite the 49names of refs as specified by `GIT_NAMESPACE`. git-upload-pack and 50git-receive-pack will ignore all references outside the specified 51namespace. 52 53The smart HTTP server, linkgit:git-http-backend[1], will pass 54GIT_NAMESPACE through to the backend programs; see 55linkgit:git-http-backend[1] for sample configuration to expose 56repository namespaces as repositories. 57 58For a simple local test, you can use linkgit:git-remote-ext[1]: 59 60---------- 61git clone ext::'git --namespace=foo %s /tmp/prefixed.git' 62---------- 63 64SECURITY 65-------- 66 67Anyone with access to any namespace within a repository can potentially 68access objects from any other namespace stored in the same repository. 69You can't directly say "give me object ABCD" if you don't have a ref to 70it, but you can do some other sneaky things like: 71 72. Claiming to push ABCD, at which point the server will optimize out the 73 need for you to actually send it. Now you have a ref to ABCD and can 74 fetch it (claiming not to have it, of course). 75 76. Requesting other refs, claiming that you have ABCD, at which point the 77 server may generate deltas against ABCD. 78 79None of this causes a problem if you only host public repositories, or 80if everyone who may read one namespace may also read everything in every 81other namespace (for instance, if everyone in an organization has read 82permission to every repository).