git reset and similar commands use -- to disambiguate between
revisions and paths on the command line. The same syntax is not
necessary to specify a revision to git checkout (for convenience
and historical reasons, revisions are preferred over paths), but
for consistency it is accepted:
git checkout master --; # check out master branch, not "master" file.
The autovivification of branches introduced by 70c9ac2f1 (DWIM "git
checkout frotz" to "git checkout -b frotz origin/frotz", 2009-10-18)
is currently disabled by that syntax, for no good reason. Paranoid
scripts can still use
git checkout --no-guess master
or even better,
old=$(git rev-parse --verify HEAD)
new=$(git rev-parse --verify refs/heads/master^0)
git read-tree -m -u --exclude-standard $old $new
git symbolic-ref -m "$me: switching branches" HEAD refs/heads/master
Requested-by: Dun Peal <dunpealer@xxxxxxxxx>
Signed-off-by: Jonathan Nieder <jrnieder@xxxxxxxxx>
---
Junio C Hamano wrote:
> That looks simpler than what I just did. Can we have a few tests, too?
Sure. The tests are not too heavy, though (e.g., no "ambiguous
ref" stuff).
>> - !check_filename(NULL, arg) &&
>> + (has_dash_dash || !check_filename(NULL, arg)) &&
>> argc == 1) {
Should have been (argc == 2) in the has_dash_dash case.
builtin/checkout.c | 19 ++++++---
t/t2010-checkout-ambiguous.sh | 83 +++++++++++++++++++++++++++++++++++++++++
2 files changed, 96 insertions(+), 6 deletions(-)
diff --git a/builtin/checkout.c b/builtin/checkout.c
index 9240faf..6c3de9f 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -771,6 +771,12 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
* <ref> must be a valid tree, everything after the '--' must be
* a path.
*
+ * Except: with no paths, if <something> does not resolve as
+ * an object, no -t nor -b was given, and there is a tracking
+ * branch whose name is <something> in one and only one remote,
+ * then this is a short-hand to fork local <something> from
+ * that remote-tracking branch.
+ *
* case 2: git checkout -- [<paths>]
*
* everything after the '--' must be paths.
@@ -808,23 +814,24 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
arg = "@{-1}";
if (get_sha1_mb(arg, rev)) {
- if (has_dash_dash) /* case (1) */
- die("invalid reference: %s", arg);
+ trace_printf("trace: guess = %d\n", dwim_new_local_branch);
if (!patch_mode &&
dwim_new_local_branch &&
opts.track == BRANCH_TRACK_UNSPECIFIED &&
!opts.new_branch &&
- !check_filename(NULL, arg) &&
- argc == 1) {
+ (has_dash_dash || !check_filename(NULL, arg)) &&
+ (argc == has_dash_dash ? 2 : 1)) {
const char *remote = unique_tracking_name(arg);
if (!remote || get_sha1(remote, rev))
goto no_reference;
opts.new_branch = arg;
arg = remote;
/* DWIMmed to create local branch */
- }
- else
+ } else if (has_dash_dash) { /* case (1) */
+ die("invalid reference: %s", arg);
+ } else {
goto no_reference;
+ }
}
/* we can't end up being in (2) anymore, eat the argument */
diff --git a/t/t2010-checkout-ambiguous.sh b/t/t2010-checkout-ambiguous.sh
index 7cc0a35..80ac7b5 100755
--- a/t/t2010-checkout-ambiguous.sh
+++ b/t/t2010-checkout-ambiguous.sh
@@ -4,10 +4,25 @@ test_description='checkout and pathspecs/refspecs ambiguities'
. ./test-lib.sh
+test_branch_is () {
+ echo "refs/heads/$1" >expect &&
+ git symbolic-ref HEAD >actual &&
+ test_cmp expect actual
+}
+
test_expect_success 'setup' '
+ git init upstream &&
+ (
+ cd upstream &&
+ test_commit upstream-commit &&
+ git branch -m upstream-topic
+ ) &&
+ git remote add upstream upstream &&
+ git fetch upstream &&
echo hello >world &&
echo hello >all &&
git add all world &&
+ test_tick &&
git commit -m initial &&
git branch world
'
@@ -32,6 +47,74 @@ test_expect_success 'non ambiguous call' '
git checkout all
'
+test_expect_success "autovivification (Dscho's DWIM)" '
+ git checkout master &&
+ test_might_fail git branch -D upstream-topic &&
+ git checkout upstream-topic &&
+ git diff --exit-code upstream-topic upstream/upstream-topic &&
+ test_branch_is upstream-topic
+'
+
+test_expect_success 'autovivification with --' '
+ git checkout master &&
+ test_might_fail git branch -D upstream-topic &&
+ git checkout upstream-topic -- &&
+ git diff --exit-code upstream-topic upstream/upstream-topic &&
+ test_branch_is upstream-topic
+'
+
+test_expect_success 'no autovivification after --' '
+ git checkout master &&
+ test_might_fail git branch -D upstream-topic &&
+ test_must_fail git checkout -- upstream-topic &&
+ test_branch_is master
+'
+
+test_expect_success '--no-guess defeats autovivification' '
+ git checkout master &&
+ test_might_fail git branch -D upstream-topic &&
+ test_must_fail git checkout --no-guess upstream-topic &&
+ test_must_fail git checkout --no-guess upstream-topic -- &&
+ test_branch_is master
+'
+
+test_expect_success 'paths defeat autovivification' '
+ git checkout master &&
+ test_might_fail git branch -D upstream-topic &&
+ test_must_fail git checkout upstream-topic -- . &&
+ test_must_fail git checkout upstream-topic . &&
+ test_branch_is master
+'
+
+test_expect_success 'real branch defeats autovivification' '
+ git checkout master &&
+ git update-ref refs/heads/upstream-topic HEAD^0 &&
+ git checkout upstream-topic &&
+ test_must_fail git diff --exit-code upstream-topic upstream/upstream-topic &&
+ test_branch_is upstream-topic
+'
+
+test_expect_success '-t defeats autovivification' '
+ git checkout master &&
+ test_might_fail git branch -D upstream-topic &&
+ test_must_fail git checkout -t upstream-topic &&
+ test_branch_is master
+'
+
+test_expect_success 'checkout of remote-tracking branch detaches HEAD' '
+ git checkout master &&
+ test_might_fail git branch -D upstream-topic &&
+ git checkout upstream/upstream-topic &&
+ test_must_fail git symbolic-ref HEAD
+'
+
+test_expect_success 'checkout -t of remote-tracking branch does not detach HEAD' '
+ git checkout master &&
+ test_might_fail git branch -D upstream-topic &&
+ git checkout -t upstream/upstream-topic &&
+ test_branch_is upstream-topic
+'
+
test_expect_success 'allow the most common case' '
git checkout world &&
test "refs/heads/world" = "$(git symbolic-ref HEAD)"
--
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