branch: make create_branch accept a merge base rev
When we ran something like $ git checkout -b test master... it would fail with the message fatal: Not a valid object name: 'master...'. This was caused by the call to `create_branch` where `start_name` is expected to be a valid rev. However, git-checkout allows the branch to be a valid _merge base_ rev (i.e. with a "...") so it was possible for an invalid rev to be passed in. Make `create_branch` accept a merge base rev so that this case does not error out. As a side-effect, teach git-branch how to handle merge base revs as well. Helped-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Denton Liu <liu.denton@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Denton Liu committed
Apr 27, 2019 at 05:02 UTC
e3d6539d58238f046ff955330f6e10c447150164
5 files changed
+33
-6
Documentation/git-branch.txt
+5
-1
@@ -45,7 +45,11 @@ argument is missing it defaults to `HEAD` (i.e. the tip of the current
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branch).
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The command's second form creates a new branch head named <branchname>
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-which points to the current `HEAD`, or <start-point> if given.
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+which points to the current `HEAD`, or <start-point> if given. As a
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+special case, for <start-point>, you may use `"A...B"` as a shortcut for
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+the merge base of `A` and `B` if there is exactly one merge base. You
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+can leave out at most one of `A` and `B`, in which case it defaults to
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+`HEAD`.
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Note that this will create the new branch, but it will not switch the
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working tree to it; use "git checkout <newbranch>" to switch to the
Documentation/git-checkout.txt
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@@ -301,6 +301,10 @@ leave out at most one of `A` and `B`, in which case it defaults to `HEAD`.
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<start_point>::
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The name of a commit at which to start the new branch; see
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linkgit:git-branch[1] for details. Defaults to HEAD.
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++
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+As a special case, you may use `"A...B"` as a shortcut for the
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+merge base of `A` and `B` if there is exactly one merge base. You can
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+leave out at most one of `A` and `B`, in which case it defaults to `HEAD`.
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<tree-ish>::
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Tree to checkout from (when paths are given). If not specified,
branch.c
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-1
@@ -268,7 +268,7 @@ void create_branch(struct repository *r,
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}
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real_ref = NULL;
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- if (get_oid(start_name, &oid)) {
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+ if (get_oid_mb(start_name, &oid)) {
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if (explicit_tracking) {
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if (advice_set_upstream_failure) {
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error(_(upstream_missing), start_name);
t/t2018-checkout-branch.sh
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@@ -66,6 +66,13 @@ test_expect_success 'checkout -b to a new branch, set to HEAD' '
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do_checkout branch2
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'
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+test_expect_success 'checkout -b to a merge base' '
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+ test_when_finished "
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+ git checkout branch1 &&
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+ test_might_fail git branch -D branch2" &&
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+ git checkout -b branch2 branch1...
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+'
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+
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test_expect_success 'checkout -b to a new branch, set to an explicit ref' '
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test_when_finished "
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git checkout branch1 &&
@@ -126,6 +133,12 @@ test_expect_success 'checkout -B to an existing branch resets branch to HEAD' '
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do_checkout branch2 "" -B
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'
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+test_expect_success 'checkout -B to a merge base' '
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+ git checkout branch1 &&
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+
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+ git checkout -B branch2 branch1...
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+'
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+
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test_expect_success 'checkout -B to an existing branch from detached HEAD resets branch to HEAD' '
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git checkout $(git rev-parse --verify HEAD) &&
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t/t3200-branch.sh
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-4
@@ -42,6 +42,10 @@ test_expect_success 'git branch a/b/c should create a branch' '
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git branch a/b/c && test_path_is_file .git/refs/heads/a/b/c
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'
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+test_expect_success 'git branch mb master... should create a branch' '
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+ git branch mb master... && test_path_is_file .git/refs/heads/mb
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+'
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+
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test_expect_success 'git branch HEAD should fail' '
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test_must_fail git branch HEAD
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'
@@ -292,8 +296,8 @@ test_expect_success 'git branch --list -v with --abbrev' '
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test_expect_success 'git branch --column' '
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COLUMNS=81 git branch --column=column >actual &&
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cat >expected <<\EOF &&
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- a/b/c bam foo l * master n o/p r
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- abc bar j/k m/m master2 o/o q
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+ a/b/c bam foo l * master mb o/o q
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+ abc bar j/k m/m master2 n o/p r
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EOF
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test_cmp expected actual
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'
@@ -315,6 +319,7 @@ test_expect_success 'git branch --column with an extremely long branch name' '
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m/m
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* master
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master2
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+ mb
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n
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o/o
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o/p
@@ -332,8 +337,8 @@ test_expect_success 'git branch with column.*' '
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git config --unset column.branch &&
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git config --unset column.ui &&
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cat >expected <<\EOF &&
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- a/b/c bam foo l * master n o/p r
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- abc bar j/k m/m master2 o/o q
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+ a/b/c bam foo l * master mb o/o q
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+ abc bar j/k m/m master2 n o/p r
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EOF
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test_cmp expected actual
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'
@@ -357,6 +362,7 @@ test_expect_success 'git branch -v with column.ui ignored' '
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m/m
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* master
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master2
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+ mb
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n
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o/o
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o/p