bitbake: fetch2/git: Use git shallow fetch to implement clone_shallow_local()

This patch can make the following settings much more faster:
BB_GIT_SHALLOW = "1"
BB_GENERATE_MIRROR_TARBALLS = "1"

* The previous implementation was:
  - Make a full clone for the repo from local ud.clonedir
  - Use git-make-shallow to remove unneeded revs

  It was very slow for recipes which have a lot of SRC_URIs, for example
  vulkan-samples and docker-compose, the docker-compose can't be done after 5
  hours.

  $ bitbake vulkan-samples -cfetch
  Before: 12 minutes
  Now: 2 minutes

  $ bitbake docker-compose -cfetch
  Before: More than 300 minutes
  Now: 15 minutes

* The patch uses git shallow fetch to fetch the repo from local
  ud.clonedir:
  - For BB_GIT_SHALLOW_DEPTH: git fetch --depth <depth> rev
  - For BB_GIT_SHALLOW_REVS: git fetch --shallow-exclude=<revs> rev

  Then the git repo will be shallow, and git-make-shallow is not needed any
  more.

  And git shallow fetch will download less commits than before since it doesn't
  need "rev^" to parse the dependencies, the previous code always need 'rev^'.

(Bitbake rev: a5a569c075224fe41707cfa9123c442d1fda2fbf)

Signed-off-by: Robert Yang <liezhi.yang@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

0 files changed, 0 insertions, 0 deletions