The "split" subcommand of "git subtree" (in contrib/) incorrectly
skipped merges when it shouldn't, which was corrected.

* dw/subtree-split-do-not-drop-merge:
  contrib/subtree: fix "subtree split" skipped-merge bug

* dg/subtree-test:
  contrib/subtree: Make testing easier

"git subtree" (in contrib/) records the tag object name in the
commit log message when a subtree is added using a tag, without
peeling it down to the underlying commit.  The tag needs to be
peeled when "git subtree split" wants to work on the commit, but
the command forgot to do so.

* rm/subtree-unwrap-tags:
  contrib/subtree: unwrap tag refs

'git subtree split' can incorrectly skip a merge even when both parents
act on the subtree, provided the merge results in a tree identical to
one of the parents. Fix by copying the merge if at least one parent is
non-identical, and the non-identical parent is not an ancestor of the
identical parent.

Also, add a test case which checks that a descendant remains a
descendent on the subtree in this case.

Signed-off-by: Dave Ware <davidw@realtimegenomics.com>
Reviewed-by: David A. Greene <greened@obbligato.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Add some Makefile dependencies to ensure an updated git-subtree
gets copied to the main area before testing begins.

Signed-off-by: David A. Greene <greened@obbligato.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Test cleanups for the subtree project.

* dg/subtree-test-cleanup:
  contrib/subtree: Handle '--prefix' argument with a slash appended
  contrib/subtree: Make each test self-contained
  contrib/subtree: Add split tests
  contrib/subtree: Add merge tests
  contrib/subtree: Add tests for subtree add
  contrib/subtree: Add test for missing subtree
  contrib/subtree: Clean and refactor test code

If a subtree was added using a tag ref, the tag ref is stored in
the subtree commit message instead of the underlying commit's ref.
To split or push subsequent changes to the subtree, the subtree
command needs to unwrap the tag ref.  This patch makes it do so.

The problem was described in a message to the mailing list from
Junio C Hamano dated 29 Apr 2014, with the subject "Re: git subtree
issue in more recent versions". The archived message can be found
at <http://comments.gmane.org/gmane.comp.version-control.git/247503>.

Signed-off-by: Rob Mayoff <mayoff@dqd.com>
Signed-off-by: Jeff King <peff@peff.net>

'git subtree merge' will fail if the argument of '--prefix' has a slash
appended.

Signed-off-by: Techlive Zheng <techlivezheng@gmail.com>
Signed-off-by: David A. Greene <greened@obbligato.org>
Signed-off-by: Jeff King <peff@peff.net>

Each test runs a full repository creation and any subtree actions
needed to perform the test.  Each test starts with a clean slate,
making debugging and post-mortem analysis much easier.

Signed-off-by: Techlive Zheng <techlivezheng@gmail.com>
Signed-off-by: David A. Greene <greened@obbligato.org>
Signed-off-by: Jeff King <peff@peff.net>

Add tests to check various options to split.  Check combinations of
--prefix, --message, --annotate, --branch and --rejoin.

Signed-off-by: Techlive Zheng <techlivezheng@gmail.com>
Signed-off-by: David A. Greene <greened@obbligato.org>
Signed-off-by: Jeff King <peff@peff.net>