[PATCH v3 0/2] allow checkout and branch to create branches on a merge base

[Denton Liu <liu.denton@gmail.com>]

Thanks again for the review, Junio.

I've squashed 2/3 and 3/3 together and made that documentation change I
was talking about earlier.

---

Changes since v2:

* Squashed 2/3 with 3/3
* Document merge base syntax for <start_point> in git-checkout.txt

Changes since v1:

* Moved multiple `test_when_finished` calls that appeared in "reverse
  order" into one call that appears in the logical order
* Made create_branch handle merge base revs instead of putting a hack
  into checkout

Denton Liu (2):
  t2018: cleanup in current test
  branch: make create_branch accept a merge base rev

 Documentation/git-branch.txt   |  6 +++-
 Documentation/git-checkout.txt |  4 +++
 branch.c                       |  2 +-
 t/t2018-checkout-branch.sh     | 56 ++++++++++++++++++----------------
 t/t3200-branch.sh              | 14 ++++++---
 5 files changed, 50 insertions(+), 32 deletions(-)

Range-diff against v2:
1:  9d04faf29d = 1:  9d04faf29d t2018: cleanup in current test
2:  5e8320cd80 < -:  ---------- t2018: demonstrate checkout -b merge base bug
3:  c91c7535a7 ! 2:  bb25852740 branch: make create_branch accept a merge base rev
    @@ -41,6 +41,21 @@
      Note that this will create the new branch, but it will not switch the
      working tree to it; use "git checkout <newbranch>" to switch to the
     
    + diff --git a/Documentation/git-checkout.txt b/Documentation/git-checkout.txt
    + --- a/Documentation/git-checkout.txt
    + +++ b/Documentation/git-checkout.txt
    +@@
    + <start_point>::
    + 	The name of a commit at which to start the new branch; see
    + 	linkgit:git-branch[1] for details. Defaults to HEAD.
    +++
    ++As a special case, you may use `"A...B"` as a shortcut for the
    ++merge base of `A` and `B` if there is exactly one merge base. You can
    ++leave out at most one of `A` and `B`, in which case it defaults to `HEAD`.
    + 
    + <tree-ish>::
    + 	Tree to checkout from (when paths are given). If not specified,
    +
      diff --git a/branch.c b/branch.c
      --- a/branch.c
      +++ b/branch.c
    @@ -61,20 +76,29 @@
      	do_checkout branch2
      '
      
    --test_expect_failure 'checkout -b to a merge base' '
     +test_expect_success 'checkout -b to a merge base' '
    ++	test_when_finished "
    ++		git checkout branch1 &&
    ++		test_might_fail git branch -D branch2" &&
    ++	git checkout -b branch2 branch1...
    ++'
    ++
    + test_expect_success 'checkout -b to a new branch, set to an explicit ref' '
      	test_when_finished "
      		git checkout branch1 &&
    - 		test_might_fail git branch -D branch2" &&
     @@
      	do_checkout branch2 "" -B
      '
      
    --test_expect_failure 'checkout -B to a merge base' '
     +test_expect_success 'checkout -B to a merge base' '
    - 	git checkout branch1 &&
    ++	git checkout branch1 &&
    ++
    ++	git checkout -B branch2 branch1...
    ++'
    ++
    + test_expect_success 'checkout -B to an existing branch from detached HEAD resets branch to HEAD' '
    + 	git checkout $(git rev-parse --verify HEAD) &&
      
    - 	git checkout -B branch2 branch1...
     
      diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh
      --- a/t/t3200-branch.sh
-- 
2.21.0.1000.g11cd861522