On 18/01/18 15:35, Johannes Schindelin wrote:
>
> In the upcoming commits, we will teach the sequencer to recreate merges.
> This will be done in a very different way from the unfortunate design of
> `git rebase --preserve-merges` (which does not allow for reordering
> commits, or changing the branch topology).
>
> The main idea is to introduce new todo list commands, to support
> labeling the current revision with a given name, resetting the current
> revision to a previous state, merging labeled revisions.
I think this would be a great improvement to rebase -i, thanks for
working on it.
> This idea was developed in Git for Windows' Git garden shears (that are
> used to maintain the "thicket of branches" on top of upstream Git), and
> this patch is part of the effort to make it available to a wider
> audience, as well as to make the entire process more robust (by
> implementing it in a safe and portable language rather than a Unix shell
> script).
>
> This commit implements the commands to label, and to reset to, given
> revisions. The syntax is:
>
> label <name>
> reset <name>
If I've understood the code below correctly then reset will clobber
untracked files, this is the opposite behaviour to what happens when
tries to checkout <onto> at the start of a rebase - then it will fail if
untracked files would be overwritten.
> As a convenience shortcut, also to improve readability of the generated
> todo list, a third command is introduced: bud. It simply resets to the
> "onto" revision, i.e. the commit onto which we currently rebase.
I found the whole bud business bewildering at first, reading the other
replies it seems I wasn't the only one to be befuddled by it. Having
seen an example I can see what it's trying to do but I still think it
adds more confusion than value.
> Internally, the `label <name>` command creates the ref
> `refs/rewritten/<name>`. This makes it possible to work with the labeled
> revisions interactively, or in a scripted fashion (e.g. via the todo
> list command `exec`).
If a user has two work trees and runs a rebase in each with the same
label name, they'll clobber each other. I'd suggest storing them under
refs/rewritten/<branch-name or detached HEAD SHA> instead. If the user
tries to rebase a second worktree with the same detached HEAD as an
existing rebase then refuse to start.
> Signed-off-by: Johannes Schindelin <johannes.schinde...@gmx.de>
> ---
> git-rebase--interactive.sh | 3 +
> sequencer.c | 181
> ++++++++++++++++++++++++++++++++++++++++++++-
> 2 files changed, 180 insertions(+), 4 deletions(-)
>
> diff --git a/git-rebase--interactive.sh b/git-rebase--interactive.sh
> index d47bd29593a..3d2cd19d65a 100644
> --- a/git-rebase--interactive.sh
> +++ b/git-rebase--interactive.sh
> @@ -162,6 +162,9 @@ s, squash = use commit, but meld into previous commit
> f, fixup = like \"squash\", but discard this commit's log message
> x, exec = run command (the rest of the line) using shell
> d, drop = remove commit
> +l, label = label current HEAD with a name
> +t, reset = reset HEAD to a label
> +b, bud = reset HEAD to the revision labeled 'onto'
>
> These lines can be re-ordered; they are executed from top to bottom.
> " | git stripspace --comment-lines >>"$todo"
> diff --git a/sequencer.c b/sequencer.c
> index 4d3f60594cb..91cc55a002f 100644
> --- a/sequencer.c
> +++ b/sequencer.c
> @@ -21,6 +21,8 @@
> #include "log-tree.h"
> #include "wt-status.h"
> #include "hashmap.h"
> +#include "unpack-trees.h"
> +#include "worktree.h"
>
> #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
>
> @@ -116,6 +118,13 @@ static GIT_PATH_FUNC(rebase_path_stopped_sha,
> "rebase-merge/stopped-sha")
> static GIT_PATH_FUNC(rebase_path_rewritten_list,
> "rebase-merge/rewritten-list")
> static GIT_PATH_FUNC(rebase_path_rewritten_pending,
> "rebase-merge/rewritten-pending")
> +
> +/*
> + * The path of the file listing refs that need to be deleted after the rebase
> + * finishes. This is used by the `merge` command.
> + */
> +static GIT_PATH_FUNC(rebase_path_refs_to_delete,
> "rebase-merge/refs-to-delete")
> +
> /*
> * The following files are written by git-rebase just after parsing the
> * command-line (and are only consumed, not modified, by the sequencer).
> @@ -767,6 +776,9 @@ enum todo_command {
> TODO_SQUASH,
> /* commands that do something else than handling a single commit */
> TODO_EXEC,
> + TODO_LABEL,
> + TODO_RESET,
> + TODO_BUD,
> /* commands that do nothing but are counted for reporting progress */
> TODO_NOOP,
> TODO_DROP,
> @@ -785,6 +797,9 @@ static struct {
> { 'f', "fixup" },
> { 's', "squash" },
> { 'x', "exec" },
> + { 'l', "label" },
> + { 't', "reset" },
> + { 'b', "bud" },
> { 0, "noop" },
> { 'd', "drop" },
> { 0, NULL }
> @@ -1253,7 +1268,8 @@ static int parse_insn_line(struct todo_item *item,
> const char *bol, char *eol)
> if (skip_prefix(bol, todo_command_info[i].str, &bol)) {
> item->command = i;
> break;
> - } else if (bol[1] == ' ' && *bol == todo_command_info[i].c) {
> + } else if ((bol + 1 == eol || bol[1] == ' ') &&
> + *bol == todo_command_info[i].c) {
> bol++;
> item->command = i;
> break;
> @@ -1265,7 +1281,7 @@ static int parse_insn_line(struct todo_item *item,
> const char *bol, char *eol)
> padding = strspn(bol, " \t");
> bol += padding;
>
> - if (item->command == TODO_NOOP) {
> + if (item->command == TODO_NOOP || item->command == TODO_BUD) {
> if (bol != eol)
> return error(_("%s does not accept arguments: '%s'"),
> command_to_string(item->command), bol);
> @@ -1279,7 +1295,8 @@ static int parse_insn_line(struct todo_item *item,
> const char *bol, char *eol)
> return error(_("missing arguments for %s"),
> command_to_string(item->command));
>
> - if (item->command == TODO_EXEC) {
> + if (item->command == TODO_EXEC || item->command == TODO_LABEL ||
> + item->command == TODO_RESET) {
> item->commit = NULL;
> item->arg = bol;
> item->arg_len = (int)(eol - bol);
> @@ -1919,6 +1936,139 @@ static int do_exec(const char *command_line)
> return status;
> }
>
> +static int safe_append(const char *filename, const char *fmt, ...)
> +{
> + va_list ap;
> + struct lock_file lock = LOCK_INIT;
> + int fd = hold_lock_file_for_update(&lock, filename, 0);
> + struct strbuf buf = STRBUF_INIT;
> +
> + if (fd < 0)
> + return error_errno(_("could not lock '%s'"), filename);
> +
> + if (strbuf_read_file(&buf, filename, 0) < 0 && errno != ENOENT)
> + return error_errno(_("could not read '%s'"), filename);
> + strbuf_complete(&buf, '\n');
> + va_start(ap, fmt);
> + strbuf_vaddf(&buf, fmt, ap);
> + va_end(ap);
> +
> + if (write_in_full(fd, buf.buf, buf.len) < 0) {
> + rollback_lock_file(&lock);
> + return error_errno(_("could not write to '%s'"), filename);
> + }
> + if (commit_lock_file(&lock) < 0) {
> + rollback_lock_file(&lock);
> + return error(_("failed to finalize '%s'."), filename);
> + }
> +
> + return 0;
> +}
> +
> +static int do_label(const char *name, int len)
> +{
> + struct ref_store *refs = get_main_ref_store();
> + struct ref_transaction *transaction;
> + struct strbuf ref_name = STRBUF_INIT, err = STRBUF_INIT;
> + struct strbuf msg = STRBUF_INIT;
> + int ret = 0;
> + struct object_id head_oid;
> +
> + strbuf_addf(&ref_name, "refs/rewritten/%.*s", len, name);
> + strbuf_addf(&msg, "label '%.*s'", len, name);
The other reflog messages below have a (rebase -i) prefix
> +
> + transaction = ref_store_transaction_begin(refs, &err);
> + if (!transaction ||
> + get_oid("HEAD", &head_oid) ||
> + ref_transaction_update(transaction, ref_name.buf, &head_oid, NULL,
> + 0, msg.buf, &err) < 0 ||
> + ref_transaction_commit(transaction, &err)) {
> + error("%s", err.buf);
if get_oid() fails then err is empty so there wont be an message after
the 'error: '
> + ret = -1;
> + }
> + ref_transaction_free(transaction);
> + strbuf_release(&err);
> + strbuf_release(&msg);
> +
> + if (!ret)
> + ret = safe_append(rebase_path_refs_to_delete(),
> + "%s\n", ref_name.buf);
> + strbuf_release(&ref_name);
> +
> + return ret;
> +}
> +
> +static int do_reset(const char *name, int len)
> +{
> + struct strbuf ref_name = STRBUF_INIT;
> + struct object_id oid;
> + struct lock_file lock = LOCK_INIT;
> + struct tree_desc desc;
> + struct tree *tree;
> + struct unpack_trees_options opts;
> + int ret = 0, i;
> +
> + if (hold_locked_index(&lock, LOCK_REPORT_ON_ERROR) < 0)
> + return -1;
> +
> + for (i = 0; i < len; i++)
> + if (isspace(name[i]))
> + len = i;
If name starts with any white space then I think this effectively
truncates name to a bunch of white space which doesn't sound right. I'm
not sure how this is being called, but it might be better to clean up
name when the to-do list is parsed instead.
> +
> + strbuf_addf(&ref_name, "refs/rewritten/%.*s", len, name);
> + if (get_oid(ref_name.buf, &oid) &&
> + get_oid(ref_name.buf + strlen("refs/rewritten/"), &oid)) {
> + error(_("could not read '%s'"), ref_name.buf);
> + rollback_lock_file(&lock);
> + strbuf_release(&ref_name);
> + return -1;
> + }
> +
> + memset(&opts, 0, sizeof(opts));
> + opts.head_idx = 1;
> + opts.src_index = &the_index;
> + opts.dst_index = &the_index;
> + opts.fn = oneway_merge;
> + opts.merge = 1;
> + opts.update = 1;
> + opts.reset = 1;
> +
> + read_cache_unmerged();
> + if (!fill_tree_descriptor(&desc, &oid)) {
> + error(_("Failed to find tree of %s."), oid_to_hex(&oid));
> + rollback_lock_file(&lock);
> + free((void *)desc.buffer);
> + strbuf_release(&ref_name);
> + return -1;
> + }
> +
> + if (unpack_trees(1, &desc, &opts)) {
> + rollback_lock_file(&lock);
> + free((void *)desc.buffer);
> + strbuf_release(&ref_name);
> + return -1;
> + }
> +
> + tree = parse_tree_indirect(&oid);
> + prime_cache_tree(&the_index, tree);
> +
> + if (write_locked_index(&the_index, &lock, COMMIT_LOCK) < 0)
> + ret = error(_("could not write index"));
> + free((void *)desc.buffer);
> +
> + if (!ret) {
> + struct strbuf msg = STRBUF_INIT;
> +
> + strbuf_addf(&msg, "(rebase -i) reset '%.*s'", len, name);
> + ret = update_ref(msg.buf, "HEAD", &oid, NULL, 0,
> + UPDATE_REFS_MSG_ON_ERR);
> + strbuf_release(&msg);
> + }
> +
> + strbuf_release(&ref_name);
> + return ret;
> +}
> +
> static int is_final_fixup(struct todo_list *todo_list)
> {
> int i = todo_list->current;
> @@ -2102,7 +2252,13 @@ static int pick_commits(struct todo_list *todo_list,
> struct replay_opts *opts)
> /* `current` will be incremented below */
> todo_list->current = -1;
> }
> - } else if (!is_noop(item->command))
> + } else if (item->command == TODO_LABEL)
> + res = do_label(item->arg, item->arg_len);
> + else if (item->command == TODO_RESET)
> + res = do_reset(item->arg, item->arg_len);
> + else if (item->command == TODO_BUD)
> + res = do_reset("onto", 4);
> + else if (!is_noop(item->command))
> return error(_("unknown command %d"), item->command);
>
> todo_list->current++;
> @@ -2207,6 +2363,23 @@ static int pick_commits(struct todo_list *todo_list,
> struct replay_opts *opts)
> }
> apply_autostash(opts);
>
> + strbuf_reset(&buf);
> + if (strbuf_read_file(&buf, rebase_path_refs_to_delete(), 0)
> + > 0) {
> + char *p = buf.buf;
> + while (*p) {
> + char *eol = strchr(p, '\n');
> + if (eol)
> + *eol = '\0';
> + if (delete_ref("(rebase -i) cleanup",
> + p, NULL, 0) < 0)
> + warning(_("could not delete '%s'"), p);
> + if (!eol)
> + break;
> + p = eol + 1;
> + }
> + }
> +
> fprintf(stderr, "Successfully rebased and updated %s.\n",
> head_ref.buf);
>
>
