The normal rule is anything outside refs/heads/ is detached. This
strictens the rule a bit more: if the branch is checked out (either in
$GIT_COMMON_DIR/HEAD or any $GIT_DIR/repos/.../HEAD) then it's
detached as well.
A hint is given so the user knows where to go and do something there
if they still want to checkout undetached here.
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@xxxxxxxxx>
---
builtin/checkout.c | 78 ++++++++++++++++++++++++++++++++++++++++++++++++++
t/t2025-checkout-to.sh | 15 ++++++++--
2 files changed, 90 insertions(+), 3 deletions(-)
diff --git a/builtin/checkout.c b/builtin/checkout.c
index f961604..7b86f2b 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -433,6 +433,11 @@ struct branch_info {
const char *name; /* The short name used */
const char *path; /* The full name of a real branch */
struct commit *commit; /* The named commit */
+ /*
+ * if not null the branch is detached because it's alrady
+ * checked out in this checkout
+ */
+ char *checkout;
};
static void setup_branch_path(struct branch_info *branch)
@@ -640,6 +645,11 @@ static void update_refs_for_switch(const struct checkout_opts *opts,
if (old->path && advice_detached_head)
detach_advice(new->name);
describe_detached_head(_("HEAD is now at"), new->commit);
+ if (new->checkout && !*new->checkout)
+ fprintf(stderr, _("hint: the main checkout is holding this branch\n"));
+ else if (new->checkout)
+ fprintf(stderr, _("hint: the linked checkout %s is holding this branch\n"),
+ new->checkout);
}
} else if (new->path) { /* Switch branches. */
create_symref("HEAD", new->path, msg.buf);
@@ -982,6 +992,71 @@ static const char *unique_tracking_name(const char *name, unsigned char *sha1)
return NULL;
}
+static int check_linked_checkout(struct branch_info *new,
+ const char *name, const char *path)
+{
+ struct strbuf sb = STRBUF_INIT;
+ char *start, *end;
+ if (strbuf_read_file(&sb, path, 0) < 0)
+ return 0;
+ if (!starts_with(sb.buf, "ref:")) {
+ strbuf_release(&sb);
+ return 0;
+ }
+
+ start = sb.buf + 4;
+ while (isspace(*start))
+ start++;
+ end = start;
+ while (*end && !isspace(*end))
+ end++;
+ if (!strncmp(start, new->path, end - start) &&
+ new->path[end - start] == '\0') {
+ strbuf_release(&sb);
+ new->path = NULL; /* detach */
+ new->checkout = xstrdup(name); /* reason */
+ return 1;
+ }
+ strbuf_release(&sb);
+ return 0;
+}
+
+static void check_linked_checkouts(struct branch_info *new)
+{
+ struct strbuf path = STRBUF_INIT;
+ DIR *dir;
+ struct dirent *d;
+
+ strbuf_addf(&path, "%s/repos", get_git_common_dir());
+ if ((dir = opendir(path.buf)) == NULL)
+ return;
+
+ strbuf_reset(&path);
+ strbuf_addf(&path, "%s/HEAD", get_git_common_dir());
+ /*
+ * $GIT_COMMON_DIR/HEAD is practically outside
+ * $GIT_DIR so resolve_ref_unsafe() won't work (it
+ * uses git_path). Parse the ref ourselves.
+ */
+ if (check_linked_checkout(new, "", path.buf)) {
+ strbuf_release(&path);
+ closedir(dir);
+ return;
+ }
+
+ while ((d = readdir(dir)) != NULL) {
+ if (!strcmp(d->d_name, ".") || !strcmp(d->d_name, ".."))
+ continue;
+ strbuf_reset(&path);
+ strbuf_addf(&path, "%s/repos/%s/HEAD",
+ get_git_common_dir(), d->d_name);
+ if (check_linked_checkout(new, d->d_name, path.buf))
+ break;
+ }
+ strbuf_release(&path);
+ closedir(dir);
+}
+
static int parse_branchname_arg(int argc, const char **argv,
int dwim_new_local_branch_ok,
struct branch_info *new,
@@ -1109,6 +1184,9 @@ static int parse_branchname_arg(int argc, const char **argv,
else
new->path = NULL; /* not an existing branch */
+ if (new->path)
+ check_linked_checkouts(new);
+
new->commit = lookup_commit_reference_gently(rev, 1);
if (!new->commit) {
/* not a commit */
diff --git a/t/t2025-checkout-to.sh b/t/t2025-checkout-to.sh
index 76eae4a..f6a5c47 100755
--- a/t/t2025-checkout-to.sh
+++ b/t/t2025-checkout-to.sh
@@ -13,13 +13,14 @@ test_expect_success 'checkout --to not updating paths' '
'
test_expect_success 'checkout --to a new worktree' '
+ git rev-parse HEAD >expect &&
git checkout --to here master &&
(
cd here &&
test_cmp ../init.t init.t &&
- git symbolic-ref HEAD >actual &&
- echo refs/heads/master >expect &&
- test_cmp expect actual &&
+ ! git symbolic-ref HEAD &&
+ git rev-parse HEAD >actual &&
+ test_cmp ../expect actual &&
git fsck
)
'
@@ -36,4 +37,12 @@ test_expect_success 'checkout --to a new worktree creating new branch' '
)
'
+test_expect_success 'detach if the same branch is already checked out' '
+ (
+ cd here &&
+ git checkout newmaster &&
+ test_must_fail git symbolic-ref HEAD
+ )
+'
+
test_done
--
1.8.5.2.240.g8478abd
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