project.RemoteFetch: Handle depth cases more robustly

The fetch logic for the case where depth is set and revision is a
SHA1 has several failure modes that are not handled well by the
current logic.

1) 'git fetch <SHA1>' requires git version >= 1.8.3
2) 'git fetch <SHA1>' can be prevented by a configuration option on the server.
3) 'git fetch --depth=<N> <refspec>' can fail to contain a SHA1 specified by
   the manifest.

Each of these cases cause infinite recursion when _RemoteFetch() tries to call
itself with current_branch_only=False because current_branch_only is set to
True when depth != None.

To try to prevent the infinite recursion, we set self.clone_depth to None
before the first retry of _RemoteFetch(). This will allow the Fetch to
eventually succeed in the case where clone-depth is specified in the manifest.
A user specified depth from the init command will still recurse infinitely.

In addition, never try to fetch a SHA1 directly if the git version being used
is not at least 1.8.3.

Change-Id: I802fc17878c0929cfd63fff611633c1d3b54ecd3

0 files changed, 0 insertions, 0 deletions