From 4c68e7ddb59457efe9d3a141dc600feda86cbe67 Mon Sep 17 00:00:00 2001 From: Johannes Schindelin Date: Wed, 25 Apr 2018 14:28:54 +0200 Subject: 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 ] # The 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 parameter refers to the (possibly rewritten) revision to merge. Let's see an example of a todo list (the initial `label onto` command is an auto-generated convenience so that the label `onto` can be used to refer to the revision onto which we rebase): 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 ` 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 Signed-off-by: Junio C Hamano --- sequencer.c | 200 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 200 insertions(+) (limited to 'sequencer.c') diff --git a/sequencer.c b/sequencer.c index c9655edffa..94f4831a0c 100644 --- a/sequencer.c +++ b/sequencer.c @@ -1307,6 +1307,7 @@ 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, @@ -1327,6 +1328,7 @@ static struct { { 'x', "exec" }, { 'l', "label" }, { 't', "reset" }, + { 'm', "merge" }, { 0, "noop" }, { 'd', "drop" }, { 0, NULL } @@ -1754,9 +1756,14 @@ 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; @@ -1791,6 +1798,8 @@ 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"); @@ -1840,6 +1849,21 @@ 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'; @@ -2654,6 +2678,158 @@ 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 + /* + * In case of problems, we now want to return a positive + * value (a negative one would indicate that the `merge` + * command needs to be rescheduled). + */ + 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; @@ -2860,6 +3036,17 @@ 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))) reschedule = 1; + } else if (item->command == TODO_MERGE) { + if ((res = do_merge(item->commit, + item->arg, item->arg_len, + item->flags, opts)) < 0) + reschedule = 1; + else if (res > 0) + /* failed with merge conflicts */ + return error_with_patch(item->commit, + item->arg, + item->arg_len, opts, + res, 0); } else if (!is_noop(item->command)) return error(_("unknown command %d"), item->command); @@ -2871,6 +3058,11 @@ static int pick_commits(struct todo_list *todo_list, struct replay_opts *opts) todo_list->current--; if (save_todo(todo_list, opts)) return -1; + if (item->commit) + return error_with_patch(item->commit, + item->arg, + item->arg_len, opts, + res, 0); } todo_list->current++; @@ -3356,8 +3548,16 @@ 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'); -- cgit v1.3