Allow checkout -B <current-branch> to update the current branch

When on master, "git checkout -B master <commit>" is a more natural way to
say "git reset --keep <commit>", which was originally invented for the
exact purpose of moving to the named commit while keeping the local changes
around.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/branch.c b/branch.c
index 025a97b..f85c438 100644 (file)
--- a/branch.c
+++ b/branch.c
@@ -160,7 +160,8 @@ int validate_new_branchname(const char *name, struct strbuf *ref,
 
 void create_branch(const char *head,
                   const char *name, const char *start_name,
-                  int force, int reflog, enum branch_track track)
+                  int force, int reflog, int clobber_head,
+                  enum branch_track track)
 {
        struct ref_lock *lock = NULL;
        struct commit *commit;
@@ -175,7 +176,8 @@ void create_branch(const char *head,
                explicit_tracking = 1;
 
        if (validate_new_branchname(name, &ref, force,
-                                   track == BRANCH_TRACK_OVERRIDE)) {
+                                   track == BRANCH_TRACK_OVERRIDE ||
+                                   clobber_head)) {
                if (!force)
                        dont_change_ref = 1;
                else

diff --git a/branch.h b/branch.h
index 1285158..e125ff4 100644 (file)
--- a/branch.h
+++ b/branch.h
@@ -13,7 +13,8 @@
  * branch for (if any).
  */
 void create_branch(const char *head, const char *name, const char *start_name,
-                  int force, int reflog, enum branch_track track);
+                  int force, int reflog,
+                  int clobber_head, enum branch_track track);
 
 /*
  * Validates that the requested branch may be created, returning the

diff --git a/builtin/branch.c b/builtin/branch.c
index 24f33b2..823789f 100644 (file)
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -737,7 +737,7 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
                if (kinds != REF_LOCAL_BRANCH)
                        die(_("-a and -r options to 'git branch' do not make sense with a branch name"));
                create_branch(head, argv[0], (argc == 2) ? argv[1] : head,
-                             force_create, reflog, track);
+                             force_create, reflog, 0, track);
        } else
                usage_with_options(builtin_branch_usage, options);
 

diff --git a/builtin/checkout.c b/builtin/checkout.c
index 2a80772..ca00a85 100644 (file)
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -540,7 +540,9 @@ static void update_refs_for_switch(struct checkout_opts *opts,
                else
                        create_branch(old->name, opts->new_branch, new->name,
                                      opts->new_branch_force ? 1 : 0,
-                                     opts->new_branch_log, opts->track);
+                                     opts->new_branch_log,
+                                     opts->new_branch_force ? 1 : 0,
+                                     opts->track);
                new->name = opts->new_branch;
                setup_branch_path(new);
        }
@@ -565,8 +567,12 @@ static void update_refs_for_switch(struct checkout_opts *opts,
                create_symref("HEAD", new->path, msg.buf);
                if (!opts->quiet) {
                        if (old->path && !strcmp(new->path, old->path)) {
-                               fprintf(stderr, _("Already on '%s'\n"),
-                                       new->name);
+                               if (opts->new_branch_force)
+                                       fprintf(stderr, _("Reset branch '%s'\n"),
+                                               new->name);
+                               else
+                                       fprintf(stderr, _("Already on '%s'\n"),
+                                               new->name);
                        } else if (opts->new_branch) {
                                if (opts->branch_exists)
                                        fprintf(stderr, _("Switched to and reset branch '%s'\n"), new->name);
@@ -1057,7 +1063,8 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
                struct strbuf buf = STRBUF_INIT;
 
                opts.branch_exists = validate_new_branchname(opts.new_branch, &buf,
-                                                            !!opts.new_branch_force, 0);
+                                                            !!opts.new_branch_force,
+                                                            !!opts.new_branch_force);
 
                strbuf_release(&buf);
        }

diff --git a/t/t2018-checkout-branch.sh b/t/t2018-checkout-branch.sh
index 75874e8..2741262 100755 (executable)
--- a/t/t2018-checkout-branch.sh
+++ b/t/t2018-checkout-branch.sh
@@ -189,12 +189,13 @@ test_expect_success 'checkout -b <describe>' '
        test_cmp expect actual
 '
 
-test_expect_success 'checkout -B to the current branch fails before merging' '
+test_expect_success 'checkout -B to the current branch works' '
        git checkout branch1 &&
+       git checkout -B branch1-scratch &&
+
        setup_dirty_mergeable &&
-       git commit -mfooble &&
-       test_must_fail git checkout -B branch1 initial &&
-       test_must_fail test_dirty_mergeable
+       git checkout -B branch1-scratch initial &&
+       test_dirty_mergeable
 '
 
 test_done