switch: make --orphan switch to an empty tree
Switching and creating branches always involves knowing the <start-point> to begin the new branch from. Sometimes, people want to create a new branch that does not have any commits yet; --orphan is a flag to allow that. --orphan overrides the default of HEAD for <start-point> instead causing us to start from an empty history with all tracked files removed from the index and working tree. The use of --orphan is incompatible with specifying a <start-point>. A note on the implementation. An alternative is just create a dummy commit in-core with empty tree and switch to it. But there's a chance the commit's SHA-1 may end up somewhere permanent like reflog. It's best to make sure "commit" pointer is NULL to avoid it. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
Nguyễn Thái Ngọc Duy committed
Mar 29, 2019 at 17:39 UTC
1806c29f2eb5f7e4b5952f4fcc75f2afe279f1a4
1 file changed
+31
-8
builtin/checkout.c
+31
-8
@@ -58,6 +58,7 @@ struct checkout_opts {
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int switch_branch_doing_nothing_is_ok;
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int only_merge_on_switching_branches;
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int can_switch_when_in_progress;
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+ int orphan_from_empty_tree;
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const char *new_branch;
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const char *new_branch_force;
@@ -568,15 +569,21 @@ static int merge_working_tree(const struct checkout_opts *opts,
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{
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int ret;
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struct lock_file lock_file = LOCK_INIT;
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+ struct tree *new_tree;
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hold_locked_index(&lock_file, LOCK_DIE_ON_ERROR);
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if (read_cache_preload(NULL) < 0)
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return error(_("index file corrupt"));
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resolve_undo_clear();
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+ if (opts->new_orphan_branch && opts->orphan_from_empty_tree) {
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+ if (new_branch_info->commit)
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+ BUG("'switch --orphan' should never accept a commit as starting point");
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+ new_tree = parse_tree_indirect(the_hash_algo->empty_tree);
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+ } else
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+ new_tree = get_commit_tree(new_branch_info->commit);
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if (opts->discard_changes) {
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- ret = reset_tree(get_commit_tree(new_branch_info->commit),
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- opts, 1, writeout_error);
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+ ret = reset_tree(new_tree, opts, 1, writeout_error);
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if (ret)
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return ret;
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} else {
@@ -614,7 +621,8 @@ static int merge_working_tree(const struct checkout_opts *opts,
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&old_branch_info->commit->object.oid :
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the_hash_algo->empty_tree);
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init_tree_desc(&trees[0], tree->buffer, tree->size);
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- tree = parse_tree_indirect(&new_branch_info->commit->object.oid);
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+ parse_tree(new_tree);
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+ tree = new_tree;
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init_tree_desc(&trees[1], tree->buffer, tree->size);
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ret = unpack_trees(2, trees, &topts);
@@ -663,7 +671,7 @@ static int merge_working_tree(const struct checkout_opts *opts,
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o.verbosity = 0;
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work = write_tree_from_memory(&o);
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- ret = reset_tree(get_commit_tree(new_branch_info->commit),
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+ ret = reset_tree(new_tree,
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opts, 1,
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writeout_error);
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if (ret)
@@ -672,13 +680,13 @@ static int merge_working_tree(const struct checkout_opts *opts,
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o.branch1 = new_branch_info->name;
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o.branch2 = "local";
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ret = merge_trees(&o,
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- get_commit_tree(new_branch_info->commit),
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+ new_tree,
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work,
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get_commit_tree(old_branch_info->commit),
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&result);
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if (ret < 0)
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exit(128);
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- ret = reset_tree(get_commit_tree(new_branch_info->commit),
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+ ret = reset_tree(new_tree,
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opts, 0,
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writeout_error);
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strbuf_release(&o.obuf);
@@ -696,7 +704,7 @@ static int merge_working_tree(const struct checkout_opts *opts,
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if (write_locked_index(&the_index, &lock_file, COMMIT_LOCK))
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die(_("unable to write new index file"));
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- if (!opts->discard_changes && !opts->quiet)
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+ if (!opts->discard_changes && !opts->quiet && new_branch_info->commit)
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show_local_changes(&new_branch_info->commit->object, &opts->diff_options);
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return 0;
@@ -897,7 +905,10 @@ static void orphaned_commit_warning(struct commit *old_commit, struct commit *ne
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add_pending_object(&revs, object, oid_to_hex(&object->oid));
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for_each_ref(add_pending_uninteresting_ref, &revs);
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- add_pending_oid(&revs, "HEAD", &new_commit->object.oid, UNINTERESTING);
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+ if (new_commit)
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+ add_pending_oid(&revs, "HEAD",
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+ &new_commit->object.oid,
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+ UNINTERESTING);
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if (prepare_revision_walk(&revs))
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die(_("internal error in revision walk"));
@@ -932,6 +943,14 @@ static int switch_branches(const struct checkout_opts *opts,
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if (old_branch_info.path)
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skip_prefix(old_branch_info.path, "refs/heads/", &old_branch_info.name);
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+ if (opts->new_orphan_branch && opts->orphan_from_empty_tree) {
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+ if (new_branch_info->name)
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+ BUG("'switch --orphan' should never accept a commit as starting point");
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+ new_branch_info->commit = NULL;
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+ new_branch_info->name = "(empty)";
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+ do_merge = 1;
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+ }
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+
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if (!new_branch_info->name) {
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new_branch_info->name = "HEAD";
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new_branch_info->commit = old_branch_info.commit;
@@ -1268,6 +1287,8 @@ static int checkout_branch(struct checkout_opts *opts,
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if (opts->new_orphan_branch) {
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if (opts->track != BRANCH_TRACK_UNSPECIFIED)
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die(_("'%s' cannot be used with '%s'"), "--orphan", "-t");
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+ if (opts->orphan_from_empty_tree && new_branch_info->name)
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+ die(_("'%s' cannot take <start-point>"), "--orphan");
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} else if (opts->force_detach) {
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if (opts->track != BRANCH_TRACK_UNSPECIFIED)
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die(_("'%s' cannot be used with '%s'"), "--detach", "-t");
@@ -1553,6 +1574,7 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
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opts.accept_pathspec = 1;
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opts.implicit_detach = 1;
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opts.can_switch_when_in_progress = 1;
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+ opts.orphan_from_empty_tree = 0;
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options = parse_options_dup(checkout_options);
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options = add_common_options(&opts, options);
@@ -1589,6 +1611,7 @@ int cmd_switch(int argc, const char **argv, const char *prefix)
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opts.only_merge_on_switching_branches = 1;
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opts.implicit_detach = 0;
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opts.can_switch_when_in_progress = 0;
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+ opts.orphan_from_empty_tree = 1;
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options = parse_options_dup(switch_options);
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options = add_common_options(&opts, options);