From: phillip.wood123@gmail.com Date: Wed, 03 Apr 2024 13:42:19 GMT Subject: Re: [PATCH] rebase -i: improve error message when picking merge Message-ID: In-Reply-To: If anyone has time to review this I'd be very grateful. I've added a couple of people to the cc list who have recently contributed to the sequencer but if anyone else fancies taking a look please do. Thanks Phillip On 26/02/2024 10:58, Phillip Wood via GitGitGadget wrote: > From: Phillip Wood > > The only todo commands that accept a merge commit are "merge" and > "reset". All the other commands like "pick" or "reword" fail when they > try to pick a a merge commit and print the message > > error: commit abc123 is a merge but no -m option was given. > > followed by a hint about the command being rescheduled. This message is > designed to help the user when they cherry-pick a merge and forget to > pass "-m". For users who are rebasing the message is confusing as there > is no way for rebase to cherry-pick the merge. > > Improve the user experience by detecting the error when the todo list is > parsed rather than waiting for the "pick" command to fail and print a > message recommending the "merge" command instead. We recommend "merge" > rather than "exec git cherry-pick -m ..." on the assumption that > cherry-picking merges is relatively rare and it is more likely that the > user chose "pick" by a mistake. > > It would be possible to support cherry-picking merges by allowing the > user to pass "-m" to "pick" commands but that adds complexity to do > something that can already be achieved with > > exec git cherry-pick -m1 abc123 > > The change is relatively straight forward but is complicated slightly as > we now need to tell the parser if we're rebasing or not. > > Reported-by: Stefan Haller > Signed-off-by: Phillip Wood > --- > rebase -i: improve error message when picking merge > > Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1672%2Fphillipwood%2Frebase-reject-merges-v1 > Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1672/phillipwood/rebase-reject-merges-v1 > Pull-Request: https://github.com/gitgitgadget/git/pull/1672 > > builtin/rebase.c | 2 +- > rebase-interactive.c | 7 ++--- > sequencer.c | 49 ++++++++++++++++++++++++++++++----- > sequencer.h | 2 +- > t/t3404-rebase-interactive.sh | 33 +++++++++++++++++++++++ > 5 files changed, 81 insertions(+), 12 deletions(-) > > diff --git a/builtin/rebase.c b/builtin/rebase.c > index 5b086f651a6..a33e41c44da 100644 > --- a/builtin/rebase.c > +++ b/builtin/rebase.c > @@ -297,7 +297,7 @@ static int do_interactive_rebase(struct rebase_options *opts, unsigned flags) > else { > discard_index(&the_index); > if (todo_list_parse_insn_buffer(the_repository, todo_list.buf.buf, > - &todo_list)) > + &todo_list, 1)) > BUG("unusable todo list"); > > ret = complete_action(the_repository, &replay, flags, > diff --git a/rebase-interactive.c b/rebase-interactive.c > index d9718409b3d..78d5ed1a41d 100644 > --- a/rebase-interactive.c > +++ b/rebase-interactive.c > @@ -114,7 +114,8 @@ int edit_todo_list(struct repository *r, struct todo_list *todo_list, > * it. If there is an error, we do not return, because the user > * might want to fix it in the first place. */ > if (!initial) > - incorrect = todo_list_parse_insn_buffer(r, todo_list->buf.buf, todo_list) | > + incorrect = todo_list_parse_insn_buffer(r, todo_list->buf.buf, > + todo_list, 1) | > file_exists(rebase_path_dropped()); > > if (todo_list_write_to_file(r, todo_list, todo_file, shortrevisions, shortonto, > @@ -134,7 +135,7 @@ int edit_todo_list(struct repository *r, struct todo_list *todo_list, > if (initial && new_todo->buf.len == 0) > return -3; > > - if (todo_list_parse_insn_buffer(r, new_todo->buf.buf, new_todo)) { > + if (todo_list_parse_insn_buffer(r, new_todo->buf.buf, new_todo, 1)) { > fprintf(stderr, _(edit_todo_list_advice)); > return -4; > } > @@ -234,7 +235,7 @@ int todo_list_check_against_backup(struct repository *r, struct todo_list *todo_ > int res = 0; > > if (strbuf_read_file(&backup.buf, rebase_path_todo_backup(), 0) > 0) { > - todo_list_parse_insn_buffer(r, backup.buf.buf, &backup); > + todo_list_parse_insn_buffer(r, backup.buf.buf, &backup, 1); > res = todo_list_check(&backup, todo_list); > } > > diff --git a/sequencer.c b/sequencer.c > index 91de546b323..cf808c24d20 100644 > --- a/sequencer.c > +++ b/sequencer.c > @@ -2550,8 +2550,37 @@ static int check_label_or_ref_arg(enum todo_command command, const char *arg) > return 0; > } > > +static int error_merge_commit(enum todo_command command) > +{ > + switch(command) { > + case TODO_PICK: > + return error(_("'%s' does not accept merge commits, " > + "please use '%s'"), > + todo_command_info[command].str, "merge -C"); > + > + case TODO_REWORD: > + return error(_("'%s' does not accept merge commits, " > + "please use '%s'"), > + todo_command_info[command].str, "merge -c"); > + > + case TODO_EDIT: > + return error(_("'%s' does not accept merge commits, " > + "please use '%s' followed by '%s'"), > + todo_command_info[command].str, > + "merge -C", "break"); > + > + case TODO_FIXUP: > + case TODO_SQUASH: > + return error(_("cannot squash merge commit into another commit")); > + > + default: > + BUG("unexpected todo_command"); > + } > +} > + > static int parse_insn_line(struct repository *r, struct todo_item *item, > - const char *buf, const char *bol, char *eol) > + const char *buf, const char *bol, char *eol, > + int rebasing) > { > struct object_id commit_oid; > char *end_of_object_name; > @@ -2655,7 +2684,12 @@ static int parse_insn_line(struct repository *r, struct todo_item *item, > return status; > > item->commit = lookup_commit_reference(r, &commit_oid); > - return item->commit ? 0 : -1; > + if (!item->commit) > + return -1; > + if (rebasing && item->command != TODO_MERGE && > + item->commit->parents && item->commit->parents->next) > + return error_merge_commit(item->command); > + return 0; > } > > int sequencer_get_last_command(struct repository *r UNUSED, enum replay_action *action) > @@ -2686,7 +2720,7 @@ int sequencer_get_last_command(struct repository *r UNUSED, enum replay_action * > } > > int todo_list_parse_insn_buffer(struct repository *r, char *buf, > - struct todo_list *todo_list) > + struct todo_list *todo_list, int rebasing) > { > struct todo_item *item; > char *p = buf, *next_p; > @@ -2704,7 +2738,7 @@ int todo_list_parse_insn_buffer(struct repository *r, char *buf, > > item = append_new_todo(todo_list); > item->offset_in_buf = p - todo_list->buf.buf; > - if (parse_insn_line(r, item, buf, p, eol)) { > + if (parse_insn_line(r, item, buf, p, eol, rebasing)) { > res = error(_("invalid line %d: %.*s"), > i, (int)(eol - p), p); > item->command = TODO_COMMENT + 1; > @@ -2852,7 +2886,8 @@ static int read_populate_todo(struct repository *r, > if (strbuf_read_file_or_whine(&todo_list->buf, todo_file) < 0) > return -1; > > - res = todo_list_parse_insn_buffer(r, todo_list->buf.buf, todo_list); > + res = todo_list_parse_insn_buffer(r, todo_list->buf.buf, todo_list, > + is_rebase_i(opts)); > if (res) { > if (is_rebase_i(opts)) > return error(_("please fix this using " > @@ -2882,7 +2917,7 @@ static int read_populate_todo(struct repository *r, > struct todo_list done = TODO_LIST_INIT; > > if (strbuf_read_file(&done.buf, rebase_path_done(), 0) > 0 && > - !todo_list_parse_insn_buffer(r, done.buf.buf, &done)) > + !todo_list_parse_insn_buffer(r, done.buf.buf, &done, 1)) > todo_list->done_nr = count_commands(&done); > else > todo_list->done_nr = 0; > @@ -6286,7 +6321,7 @@ int complete_action(struct repository *r, struct replay_opts *opts, unsigned fla > strbuf_release(&buf2); > /* Nothing is done yet, and we're reparsing, so let's reset the count */ > new_todo.total_nr = 0; > - if (todo_list_parse_insn_buffer(r, new_todo.buf.buf, &new_todo) < 0) > + if (todo_list_parse_insn_buffer(r, new_todo.buf.buf, &new_todo, 1) < 0) > BUG("invalid todo list after expanding IDs:\n%s", > new_todo.buf.buf); > > diff --git a/sequencer.h b/sequencer.h > index dcef7bb99c0..ed2c4b38514 100644 > --- a/sequencer.h > +++ b/sequencer.h > @@ -136,7 +136,7 @@ struct todo_list { > } > > int todo_list_parse_insn_buffer(struct repository *r, char *buf, > - struct todo_list *todo_list); > + struct todo_list *todo_list, int rebasing); > int todo_list_write_to_file(struct repository *r, struct todo_list *todo_list, > const char *file, const char *shortrevisions, > const char *shortonto, int num, unsigned flags); > diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh > index 64b641002e4..20b8589ad07 100755 > --- a/t/t3404-rebase-interactive.sh > +++ b/t/t3404-rebase-interactive.sh > @@ -2203,6 +2203,39 @@ test_expect_success 'bad labels and refs rejected when parsing todo list' ' > test_path_is_missing execed > ' > > +test_expect_success 'non-merge commands reject merge commits' ' > + test_when_finished "test_might_fail git rebase --abort" && > + git checkout E && > + git merge I && > + oid=$(git rev-parse HEAD) && > + cat >todo <<-EOF && > + pick $oid > + reword $oid > + edit $oid > + fixup $oid > + squash $oid > + EOF > + ( > + set_replace_editor todo && > + test_must_fail git rebase -i HEAD 2>actual > + ) && > + cat >expect <<-EOF && > + error: ${SQ}pick${SQ} does not accept merge commits, please use ${SQ}merge -C${SQ} > + error: invalid line 1: pick $oid > + error: ${SQ}reword${SQ} does not accept merge commits, please use ${SQ}merge -c${SQ} > + error: invalid line 2: reword $oid > + error: ${SQ}edit${SQ} does not accept merge commits, please use ${SQ}merge -C${SQ} followed by ${SQ}break${SQ} > + error: invalid line 3: edit $oid > + error: cannot squash merge commit into another commit > + error: invalid line 4: fixup $oid > + error: cannot squash merge commit into another commit > + error: invalid line 5: squash $oid > + You can fix this with ${SQ}git rebase --edit-todo${SQ} and then run ${SQ}git rebase --continue${SQ}. > + Or you can abort the rebase with ${SQ}git rebase --abort${SQ}. > + EOF > + test_cmp expect actual > +' > + > # This must be the last test in this file > test_expect_success '$EDITOR and friends are unchanged' ' > test_editor_unchanged > > base-commit: c875e0b8e036c12cfbf6531962108a063c7a821c