minghua minghua - 3 months ago 62
Git Question

git shallow clone (clone --depth) misses remote branches

After cloning a remote repository it does not show any remote branch by -a option. What could be the problem? How to debug it? In this snippet two of the remote branches are not shown:

$ git clone --depth 1 git://git.savannah.gnu.org/pythonwebkit.git
$ cd pythonwebkit
$ git branch -a
* master
remotes/origin/HEAD -> origin/master
remotes/origin/master
$ git --version
git version 1.8.3.1


Tried the same command on another machine, it works well:

$ git clone --depth 1 git://git.savannah.gnu.org/pythonwebkit.git
Receiving objects: 100% (186886/186886), 818.91 MiB | 3.44 MiB/s, done.
$ cd pythonwebkit/
$ git branch -a
* master
remotes/origin/HEAD -> origin/master
remotes/origin/debian
remotes/origin/master
remotes/origin/python_codegen
$ git --version
git version 1.7.1


Tried also cloning another repo, it works well. Though I can try it on this machine again, but it would be better to know what's wrong.

Any suggestions or hints will be more than welcome.

Edit: Answer summary: Since git version 1.8.3.2 the "--depth" and "--no-single-branch" need to be used together to get the same behavior as before. This is deemed a bug fix.

Answer

The behavior is correct, after the last revision the master-branch is (since this is the primary remote's HEAD) the only remote-branch in the repository:

florianb$ git branch -a
        * master
          remotes/origin/HEAD -> origin/master
          remotes/origin/master

The full clone offers new (all) branches:

florianb$ git branch -a
        * master
          remotes/origin/HEAD -> origin/master
          remotes/origin/debian
          remotes/origin/master
          remotes/origin/python_codegen

Shallow clones

Due to the shallow-description in the technical documentation, a "git-clone --depth 20 repo [...] result[s in] commit chains with a length of at most 20." A shallow clone therefore should contain the requested depth of commits, from the tip of a branch.

As - in addition - the documentation of git clone for the --single-branch-option describes:

"Clone only the history leading to the tip of a single branch, either specified by the --branch option or the primary branch remote's HEAD points at. When creating a shallow clone with the --depth option, this is the default, unless --no-single-branch is given to fetch the histories near the tips of all branches."

Therefore a shallow clone (with the depth-option) only fetches only one single branch (at your requested depth).


Unfortunately both options (--depth and --single-branch) have been faulty in the past and the use of shallow clones implicits unresolved problems (as you can read in the link I posted above), which is caused by the given history-rewrite. This leads in overall to somewhat complicated behavior in special cases.

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