rebase -i: learn to rebase root commit

diff --git a/builtin-checkout.c b/builtin-checkout.c
index b572b3bf69c791912717eae313942316cd77ac37..c2c05613b67d7cc8bd3500bdbca4fc3533afaeee 100644 (file)
--- a/builtin-checkout.c
+++ b/builtin-checkout.c
@@ -47,7 +47,7 @@ static int post_checkout_hook(struct commit *old, struct commit *new,
 
        memset(&proc, 0, sizeof(proc));
        argv[0] = name;
-       argv[1] = xstrdup(sha1_to_hex(old->object.sha1));
+       argv[1] = xstrdup(sha1_to_hex(old ? old->object.sha1 : null_sha1));
        argv[2] = xstrdup(sha1_to_hex(new->object.sha1));
        argv[3] = changed ? "1" : "0";
        argv[4] = NULL;
@@ -206,6 +206,8 @@ static int checkout_merged(int pos, struct checkout *state)
        ce = make_cache_entry(create_ce_mode(active_cache[pos+1]->ce_mode),
                              sha1,
                              path, 2, 0);
+       if (!ce)
+               die("make_cache_entry failed for path '%s'", path);
        status = checkout_entry(ce, state, NULL);
        return status;
 }
@@ -226,7 +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);
@@ -308,8 +311,7 @@ static void show_local_changes(struct object *head)
 
 static void describe_detached_head(char *msg, struct commit *commit)
 {
-       struct strbuf sb;
-       strbuf_init(&sb, 0);
+       struct strbuf sb = STRBUF_INIT;
        parse_commit(commit);
        pretty_print_commit(CMIT_FMT_ONELINE, commit, &sb, 0, NULL, NULL, 0, 0);
        fprintf(stderr, "%s %s... %s\n", msg,
@@ -358,8 +360,7 @@ struct branch_info {
 
 static void setup_branch_path(struct branch_info *branch)
 {
-       struct strbuf buf;
-       strbuf_init(&buf, 0);
+       struct strbuf buf = STRBUF_INIT;
        strbuf_addstr(&buf, "refs/heads/");
        strbuf_addstr(&buf, branch->name);
        branch->path = strbuf_detach(&buf, NULL);
@@ -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;
@@ -482,7 +484,7 @@ static void update_refs_for_switch(struct checkout_opts *opts,
                                   struct branch_info *old,
                                   struct branch_info *new)
 {
-       struct strbuf msg;
+       struct strbuf msg = STRBUF_INIT;
        const char *old_desc;
        if (opts->new_branch) {
                create_branch(old->name, opts->new_branch, new->name, 0,
@@ -491,12 +493,11 @@ static void update_refs_for_switch(struct checkout_opts *opts,
                setup_branch_path(new);
        }
 
-       strbuf_init(&msg, 0);
        old_desc = old->name;
-       if (!old_desc)
+       if (!old_desc && old->commit)
                old_desc = sha1_to_hex(old->commit->object.sha1);
        strbuf_addf(&msg, "checkout: moving from %s to %s",
-                   old_desc, new->name);
+                   old_desc ? old_desc : "(invalid)", new->name);
 
        if (new->path) {
                create_symref("HEAD", new->path, msg.buf);
@@ -552,10 +553,10 @@ static int switch_branches(struct checkout_opts *opts, struct branch_info *new)
         * a new commit, we want to mention the old commit once more
         * to remind the user that it might be lost.
         */
-       if (!opts->quiet && !old.path && new->commit != old.commit)
+       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);
@@ -636,9 +637,6 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
                git_xmerge_config("merge.conflictstyle", conflict_style, NULL);
        }
 
-       if (!opts.new_branch && (opts.track != git_branch_track))
-               die("git checkout: --track and --no-track require -b");
-
        if (opts.force && opts.merge)
                die("git checkout: -f and -m are incompatible");
 
@@ -736,8 +734,7 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
        }
 
        if (opts.new_branch) {
-               struct strbuf buf;
-               strbuf_init(&buf, 0);
+               struct strbuf buf = STRBUF_INIT;
                strbuf_addstr(&buf, "refs/heads/");
                strbuf_addstr(&buf, opts.new_branch);
                if (!get_sha1(buf.buf, rev))