Hi Jonathan, Le 26/11/2019 à 19:41, Jonathan Tan a écrit : >> Currently, complete_action(), used by builtin/rebase.c to start a new >> rebase, calls sequencer_continue() to do it. Before the former calls >> pick_commits(), it >> >> - calls read_and_refresh_cache() -- this is unnecessary here as we've >> just called require_clean_work_tree() in complete_action() > > require_clean_work_tree() and read_and_refresh_cache() seem to be > different functions - can you explain why running the former is a good > substitute for running the latter? > They both refresh the index. require_clean_work_tree(), called when starting a new rebase, will also check if there are any unstaged or uncommitted changes, in which case we do not want to start a rebase. This is not what we want when resuming a rebase (with `rebase --continue'), because the changes might be the result of a conflict resolution. In this case, the last commit is amended, and the rebase is resumed. >> - calls read_populate_opts() -- this is unnecessary as we're starting a >> new rebase, so `opts' is fully populated > > My comment from [1] has not been addressed. Quoting it here: > >> So complete_action() (the function modified in this commit) is called >> only by do_interactive_rebase() (in builtin/rebase.c), which is only >> called by run_rebase_interactive() (in builtin/rebase.c) when command is >> ACTION_NONE, so indeed, we're starting a new rebase. But where the >> options fully populated? I see that in do_interactive_rebase(), it is >> initialized with get_replay_opts(), but that seems different from >> read_populate_opts(). > > [1] https://lore.kernel.org/git/20191119204146.168001-1-jonathantanmy@xxxxxxxxxx/ > Sorry. For the first part of your comment, I added a comment at the beginning of the message, although I did _not_ include an analysis on when complete_action() is used. get_replay_opts() converts a `struct rebase_options' (which contains the arguments passed to `git rebase') into a `struct replay_opts' which can be used by the sequencer, whereas read_populate_opts() loads the options from the disk. So, when are they written to the disk? In do_interactive_rebase() (builtin/rebase.c), after using get_replay_opts() to convert `opts' to `replay', init_basic_state() is called, which calls write_basic_state(), which write the options to the disk. Then, until complete_action() is called, `opts' is not modified. >> - loads the todo list -- this is unnecessary as we've just populated >> the todo list in complete_action() > > Both functions indeed have their own todo lists that they pass to > pick_commits(), but I don't see (at least, by glancing at the code) that > both these todo lists are identical. > Near the end of complete_action(), the todo list is written to the disk. The destination is obtained with rebase_path_todo(). read_populate_todo() will read a file and parse it. In the case of `rebase -i', the location is obtained with rebase_path_todo(), and only `total_nr' will be modified to contain the number of commands done and todo. In the case of a new rebase, the done list might not be empty after tajjimh skip_unnecessary_picks() from complete_action(). Skipped commands are moved from the todo list to the done list. As `total_nr' is not changed by skip_unnecessary_picks(), it is also equal to the number of commands remaining in the todo list and in the done list. So, when read_populate_todo() reads the list and the done list from the disk, as they should not have been modified, `total_nr' should remain the same, too. The only thing that can change is the internal buffer (`buf'), because skip_unnecessary_picks() don’t change it. Since ag/sequencer-reduce-rewriting-todo, it is no longer a textual representation of the todo list. Each command contains a pointer to a location in the buffer and a length to represent its argument. >> - commits any staged changes -- this is unnecessary as we're starting a >> new rebase, so there are no staged changes >> - calls record_in_rewritten() -- this is unnecessary as we're starting >> a new rebase. > > OK - I don't know enough about the rebase mechanism to verify these, but > these seem reasonable to me. > Cheers, Alban
