sequencer: introduce the `merge` command
This patch is part of the effort to reimplement `--preserve-merges` with
a substantially improved design, a design that has been developed in the
Git for Windows project to maintain the dozens of Windows-specific patch
series on top of upstream Git.
The previous patch implemented the `label` and `reset` commands to label
commits and to reset to labeled commits. This patch adds the `merge`
command, with the following syntax:
merge [-C <commit>] <rev> # <oneline>
The <commit> parameter in this instance is the *original* merge commit,
whose author and message will be used for the merge commit that is about
to be created.
The <rev> parameter refers to the (possibly rewritten) revision to
merge. Let's see an example of a todo list:
label onto
# Branch abc
reset onto
pick deadbeef Hello, world!
label abc
reset onto
pick cafecafe And now for something completely different
merge -C baaabaaa abc # Merge the branch 'abc' into master
To edit the merge commit's message (a "reword" for merges, if you will),
use `-c` (lower-case) instead of `-C`; this convention was borrowed from
`git commit` that also supports `-c` and `-C` with similar meanings.
To create *new* merges, i.e. without copying the commit message from an
existing commit, simply omit the `-C <commit>` parameter (which will
open an editor for the merge message):
merge abc
This comes in handy when splitting a branch into two or more branches.
Note: this patch only adds support for recursive merges, to keep things
simple. Support for octopus merges will be added later in a separate
patch series, support for merges using strategies other than the
recursive merge is left for the future.
Signed-off-by: Johannes Schindelin <johannes.schinde...@gmx.de>
# The commit message #2 will be skipped:
# fixup! sequencer: introduce the `merge` command
---
git-rebase--interactive.sh | 4 +
sequencer.c | 184 +++++++++++++++++++++++++++++++++++++
2 files changed, 188 insertions(+)
diff --git a/git-rebase--interactive.sh b/git-rebase--interactive.sh
index e8d3a7d7588..ccd5254d1c9 100644
--- a/git-rebase--interactive.sh
+++ b/git-rebase--interactive.sh
@@ -164,6 +164,10 @@ x, exec <commit> = run command (the rest of the line)
using shell
d, drop <commit> = remove commit
l, label <label> = label current HEAD with a name
t, reset <label> = reset HEAD to a label
+m, merge [-C <commit> | -c <commit>] <label> [# <oneline>]
+. create a merge commit using the original merge commit's
+. message (or the oneline, if no original merge commit was
+. specified). Use -c <commit> to reword the commit message.
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 9e09026b594..90b2fac96b1 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -1305,6 +1305,7 @@ enum todo_command {
TODO_EXEC,
TODO_LABEL,
TODO_RESET,
+ TODO_MERGE,
/* commands that do nothing but are counted for reporting progress */
TODO_NOOP,
TODO_DROP,
@@ -1325,6 +1326,7 @@ static struct {
{ 'x', "exec" },
{ 'l', "label" },
{ 't', "reset" },
+ { 'm', "merge" },
{ 0, "noop" },
{ 'd', "drop" },
{ 0, NULL }
@@ -1752,9 +1754,14 @@ static int read_and_refresh_cache(struct replay_opts
*opts)
return 0;
}
+enum todo_item_flags {
+ TODO_EDIT_MERGE_MSG = 1
+};
+
struct todo_item {
enum todo_command command;
struct commit *commit;
+ unsigned int flags;
const char *arg;
int arg_len;
size_t offset_in_buf;
@@ -1789,6 +1796,8 @@ static int parse_insn_line(struct todo_item *item, const
char *bol, char *eol)
char *end_of_object_name;
int i, saved, status, padding;
+ item->flags = 0;
+
/* left-trim */
bol += strspn(bol, " \t");
@@ -1838,6 +1847,21 @@ static int parse_insn_line(struct todo_item *item, const
char *bol, char *eol)
return 0;
}
+ if (item->command == TODO_MERGE) {
+ if (skip_prefix(bol, "-C", &bol))
+ bol += strspn(bol, " \t");
+ else if (skip_prefix(bol, "-c", &bol)) {
+ bol += strspn(bol, " \t");
+ item->flags |= TODO_EDIT_MERGE_MSG;
+ } else {
+ item->flags |= TODO_EDIT_MERGE_MSG;
+ item->commit = NULL;
+ item->arg = bol;
+ item->arg_len = (int)(eol - bol);
+ return 0;
+ }
+ }
+
end_of_object_name = (char *) bol + strcspn(bol, " \t\n");
saved = *end_of_object_name;
*end_of_object_name = '\0';
@@ -2646,6 +2670,153 @@ static int do_reset(const char *name, int len, struct
replay_opts *opts)
return ret;
}
+static int do_merge(struct commit *commit, const char *arg, int arg_len,
+ int flags, struct replay_opts *opts)
+{
+ int run_commit_flags = (flags & TODO_EDIT_MERGE_MSG) ?
+ EDIT_MSG | VERIFY_MSG : 0;
+ struct strbuf ref_name = STRBUF_INIT;
+ struct commit *head_commit, *merge_commit, *i;
+ struct commit_list *bases, *j, *reversed = NULL;
+ struct merge_options o;
+ int merge_arg_len, oneline_offset, ret;
+ static struct lock_file lock;
+ const char *p;
+
+ if (hold_locked_index(&lock, LOCK_REPORT_ON_ERROR) < 0) {
+ ret = -1;
+ goto leave_merge;
+ }
+
+ head_commit = lookup_commit_reference_by_name("HEAD");
+ if (!head_commit) {
+ ret = error(_("cannot merge without a current revision"));
+ goto leave_merge;
+ }
+
+ oneline_offset = arg_len;
+ merge_arg_len = strcspn(arg, " \t\n");
+ p = arg + merge_arg_len;
+ p += strspn(p, " \t\n");
+ if (*p == '#' && (!p[1] || isspace(p[1]))) {
+ p += 1 + strspn(p + 1, " \t\n");
+ oneline_offset = p - arg;
+ } else if (p - arg < arg_len)
+ BUG("octopus merges are not supported yet: '%s'", p);
+
+ strbuf_addf(&ref_name, "refs/rewritten/%.*s", merge_arg_len, arg);
+ merge_commit = lookup_commit_reference_by_name(ref_name.buf);
+ if (!merge_commit) {
+ /* fall back to non-rewritten ref or commit */
+ strbuf_splice(&ref_name, 0, strlen("refs/rewritten/"), "", 0);
+ merge_commit = lookup_commit_reference_by_name(ref_name.buf);
+ }
+
+ if (!merge_commit) {
+ ret = error(_("could not resolve '%s'"), ref_name.buf);
+ goto leave_merge;
+ }
+
+ if (commit) {
+ const char *message = get_commit_buffer(commit, NULL);
+ const char *body;
+ int len;
+
+ if (!message) {
+ ret = error(_("could not get commit message of '%s'"),
+ oid_to_hex(&commit->object.oid));
+ goto leave_merge;
+ }
+ write_author_script(message);
+ find_commit_subject(message, &body);
+ len = strlen(body);
+ ret = write_message(body, len, git_path_merge_msg(), 0);
+ unuse_commit_buffer(commit, message);
+ if (ret) {
+ error_errno(_("could not write '%s'"),
+ git_path_merge_msg());
+ goto leave_merge;
+ }
+ } else {
+ struct strbuf buf = STRBUF_INIT;
+ int len;
+
+ strbuf_addf(&buf, "author %s", git_author_info(0));
+ write_author_script(buf.buf);
+ strbuf_reset(&buf);
+
+ if (oneline_offset < arg_len) {
+ p = arg + oneline_offset;
+ len = arg_len - oneline_offset;
+ } else {
+ strbuf_addf(&buf, "Merge branch '%.*s'",
+ merge_arg_len, arg);
+ p = buf.buf;
+ len = buf.len;
+ }
+
+ ret = write_message(p, len, git_path_merge_msg(), 0);
+ strbuf_release(&buf);
+ if (ret) {
+ error_errno(_("could not write '%s'"),
+ git_path_merge_msg());
+ goto leave_merge;
+ }
+ }
+
+ write_message(oid_to_hex(&merge_commit->object.oid), GIT_SHA1_HEXSZ,
+ git_path_merge_head(), 0);
+ write_message("no-ff", 5, git_path_merge_mode(), 0);
+
+ bases = get_merge_bases(head_commit, merge_commit);
+ for (j = bases; j; j = j->next)
+ commit_list_insert(j->item, &reversed);
+ free_commit_list(bases);
+
+ read_cache();
+ init_merge_options(&o);
+ o.branch1 = "HEAD";
+ o.branch2 = ref_name.buf;
+ o.buffer_output = 2;
+
+ ret = merge_recursive(&o, head_commit, merge_commit, reversed, &i);
+ if (ret <= 0)
+ fputs(o.obuf.buf, stdout);
+ strbuf_release(&o.obuf);
+ if (ret < 0) {
+ error(_("could not even attempt to merge '%.*s'"),
+ merge_arg_len, arg);
+ goto leave_merge;
+ }
+ /*
+ * The return value of merge_recursive() is 1 on clean, and 0 on
+ * unclean merge.
+ *
+ * Let's reverse that, so that do_merge() returns 0 upon success and
+ * 1 upon failed merge (keeping the return value -1 for the cases where
+ * we will want to reschedule the `merge` command).
+ */
+ ret = !ret;
+
+ if (active_cache_changed &&
+ write_locked_index(&the_index, &lock, COMMIT_LOCK)) {
+ ret = error(_("merge: Unable to write new index file"));
+ goto leave_merge;
+ }
+
+ rollback_lock_file(&lock);
+ if (ret)
+ rerere(opts->allow_rerere_auto);
+ else
+ ret = run_git_commit(git_path_merge_msg(), opts,
+ run_commit_flags);
+
+leave_merge:
+ strbuf_release(&ref_name);
+ rollback_lock_file(&lock);
+ return ret;
+}
+
static int is_final_fixup(struct todo_list *todo_list)
{
int i = todo_list->current;
@@ -2852,6 +3023,11 @@ static int pick_commits(struct todo_list *todo_list,
struct replay_opts *opts)
} else if (item->command == TODO_RESET) {
if ((res = do_reset(item->arg, item->arg_len, opts)))
goto reschedule;
+ } else if (item->command == TODO_MERGE) {
+ res = do_merge(item->commit, item->arg, item->arg_len,
+ item->flags, opts);
+ if (res < 0)
+ goto reschedule;
} else if (!is_noop(item->command))
return error(_("unknown command %d"), item->command);
@@ -3334,8 +3510,16 @@ int transform_todos(unsigned flags)
short_commit_name(item->commit) :
oid_to_hex(&item->commit->object.oid);
+ if (item->command == TODO_MERGE) {
+ if (item->flags & TODO_EDIT_MERGE_MSG)
+ strbuf_addstr(&buf, " -c");
+ else
+ strbuf_addstr(&buf, " -C");
+ }
+
strbuf_addf(&buf, " %s", oid);
}
+
/* add all the rest */
if (!item->arg_len)
strbuf_addch(&buf, '\n');
--
2.17.0.windows.1.4.g7e4058d72e3
