rebase -i: learn to rebase root commit

diff --git a/builtin-checkout.c b/builtin-checkout.c
index 06904c3bd3595b4c8cbc6c66d3a1b9c364381bd6..c2c05613b67d7cc8bd3500bdbca4fc3533afaeee 100644 (file)
--- a/builtin-checkout.c
+++ b/builtin-checkout.c
@@ -228,7 +228,8 @@ static int checkout_paths(struct tree *source_tree, const char **pathspec,
        struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
 
        newfd = hold_locked_index(lock_file, 1);
-       read_cache();
+       if (read_cache() < 0)
+               return error("corrupt index file");
 
        if (source_tree)
                read_tree_some(source_tree, pathspec);
@@ -371,7 +372,9 @@ static int merge_working_tree(struct checkout_opts *opts,
        int ret;
        struct lock_file *lock_file = xcalloc(1, sizeof(struct lock_file));
        int newfd = hold_locked_index(lock_file, 1);
-       read_cache();
+
+       if (read_cache() < 0)
+               return error("corrupt index file");
 
        if (opts->force) {
                ret = reset_tree(new->commit->tree, opts, 1);
@@ -397,8 +400,7 @@ static int merge_working_tree(struct checkout_opts *opts,
                }
 
                /* 2-way merge to the new branch */
-               topts.initial_checkout = (!active_nr &&
-                                         (old->commit == new->commit));
+               topts.initial_checkout = is_cache_unborn();
                topts.update = 1;
                topts.merge = 1;
                topts.gently = opts->merge;
@@ -554,7 +556,7 @@ static int switch_branches(struct checkout_opts *opts, struct branch_info *new)
        if (!opts->quiet && !old.path && old.commit && new->commit != old.commit)
                describe_detached_head("Previous HEAD position was", old.commit);
 
-       if (!old.commit) {
+       if (!old.commit && !opts->force) {
                if (!opts->quiet) {
                        fprintf(stderr, "warning: You appear to be on a branch yet to be born.\n");
                        fprintf(stderr, "warning: Forcing checkout of %s.\n", new->name);