Let git-checkout save the old branch as a symref in LAST_HEAD, and
make 'git checkout -' switch back to LAST_HEAD, like 'cd -' does in
the shell.
Signed-off-by: Thomas Rast <trast@xxxxxxxxxxxxxxx>
---
I really wished I had this earlier today. I'm just not sure if it's a
good idea, or even possible, to reserve the '-'. I can't seem to
check out a branch '-foo' with git-checkout, but it's easy to create
one with 'git branch -- -foo'. git-check-ref-format(1) doesn't forbid
it either, although the actual 'git check-ref-format -foo' exits with
status 1.
Documentation/git-checkout.txt | 3 +++
Documentation/gitrepository-layout.txt | 4 ++++
builtin-checkout.c | 26 +++++++++++++++++++++++++-
3 files changed, 32 insertions(+), 1 deletions(-)
diff --git a/Documentation/git-checkout.txt b/Documentation/git-checkout.txt
index 9cd5151..1397745 100644
--- a/Documentation/git-checkout.txt
+++ b/Documentation/git-checkout.txt
@@ -133,6 +133,9 @@ the conflicted merge in the specified paths.
+
When this parameter names a non-branch (but still a valid commit object),
your HEAD becomes 'detached'.
++
+You may also specify "`-`", which denotes the last branch you were on
+before the current HEAD.
Detached HEAD
diff --git a/Documentation/gitrepository-layout.txt b/Documentation/gitrepository-layout.txt
index 1befca9..f506c98 100644
--- a/Documentation/gitrepository-layout.txt
+++ b/Documentation/gitrepository-layout.txt
@@ -123,6 +123,10 @@ is often called 'detached HEAD', and almost all commands work
identically as normal. See linkgit:git-checkout[1] for
details.
+LAST_HEAD::
+ A symref that holds the value of HEAD before the last
+ branch switch.
+
branches::
A slightly deprecated way to store shorthands to be used
to specify URL to 'git-fetch', 'git-pull' and 'git-push'
diff --git a/builtin-checkout.c b/builtin-checkout.c
index b5dd9c0..356ad6c 100644
--- a/builtin-checkout.c
+++ b/builtin-checkout.c
@@ -480,6 +480,15 @@ static void report_tracking(struct branch_info *new)
strbuf_release(&sb);
}
+static void save_old_branch(struct branch_info *old, char *msg)
+{
+ if (old->path) {
+ create_symref("LAST_HEAD", old->path, msg);
+ } else
+ update_ref(msg, "LAST_HEAD", old->commit->object.sha1, NULL,
+ REF_NODEREF, DIE_ON_ERR);
+}
+
static void update_refs_for_switch(struct checkout_opts *opts,
struct branch_info *old,
struct branch_info *new)
@@ -505,12 +514,15 @@ static void update_refs_for_switch(struct checkout_opts *opts,
if (old->path && !strcmp(new->path, old->path))
fprintf(stderr, "Already on \"%s\"\n",
new->name);
- else
+ else {
fprintf(stderr, "Switched to%s branch \"%s\"\n",
opts->new_branch ? " a new" : "",
new->name);
+ save_old_branch(old, msg.buf);
+ }
}
} else if (strcmp(new->name, "HEAD")) {
+ save_old_branch(old, msg.buf);
update_ref(msg.buf, "HEAD", new->commit->object.sha1, NULL,
REF_NODEREF, DIE_ON_ERR);
if (!opts->quiet) {
@@ -533,6 +545,8 @@ static int switch_branches(struct checkout_opts *opts, struct branch_info *new)
int flag;
memset(&old, 0, sizeof(old));
old.path = resolve_ref("HEAD", rev, 0, &flag);
+ if (old.path)
+ old.path = strdup(old.path);
old.commit = lookup_commit_reference_gently(rev, 1);
if (!(flag & REF_ISSYMREF))
old.path = NULL;
@@ -604,6 +618,7 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
OPT_END(),
};
int has_dash_dash;
+ int flag;
memset(&opts, 0, sizeof(opts));
memset(&new, 0, sizeof(new));
@@ -671,6 +686,15 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
arg = argv[0];
has_dash_dash = (argc > 1) && !strcmp(argv[1], "--");
+ if (!strcmp(arg, "-")) {
+ arg = resolve_ref("LAST_HEAD", rev, 0, &flag);
+ if (!arg)
+ die("No last branch saved.");
+ if(!prefixcmp(arg, "refs/heads/"))
+ arg += 11;
+ arg = strdup(arg);
+ }
+
if (get_sha1(arg, rev)) {
if (has_dash_dash) /* case (1) */
die("invalid reference: %s", arg);
--
1.6.1.282.gae4091.dirty
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