Re: [PATCH v7 07/16] sequencer: refactor sequencer_add_exec_commands() to work on a todo_list

[Alban Gruin <alban.gruin@gmail.com>]

Hi Phillip,

Le 12/02/2019 à 11:52, Phillip Wood a écrit :
> Hi Alban
> 
> I think this is almost there, I've got a couple of small comments below.
> 
> On 10/02/2019 13:26, Alban Gruin wrote:
>> -%<-
>> diff --git a/builtin/rebase--interactive.c b/builtin/rebase--interactive.c
>> index df19ccaeb9..c131fd4a27 100644
>> --- a/builtin/rebase--interactive.c
>> +++ b/builtin/rebase--interactive.c
>> -%<-
>> @@ -221,6 +222,11 @@ int cmd_rebase__interactive(int argc, const char **argv, const char *prefix)
>>  		warning(_("--[no-]rebase-cousins has no effect without "
>>  			  "--rebase-merges"));
>>  
>> +	if (cmd && *cmd) {
>> +		string_list_split(&commands, cmd, '\n', -1);
> 
> I'd suggest a comment along the lines of
> /* As cmd always ends with a newline the last item is empty */
> 
>> +		--commands.nr;
> 
> Style: commands.nr--
> 
>> +	}
>> +
>>  	switch (command) {
>>  	case NONE:
>>  		if (!onto && !upstream)
>> @@ -228,7 +234,7 @@ int cmd_rebase__interactive(int argc, const char **argv, const char *prefix)
>>  
>>  		ret = do_interactive_rebase(&opts, flags, switch_to, upstream, onto,
>>  					    onto_name, squash_onto, head_name, restrict_revision,
>> -					    raw_strategies, cmd, autosquash);
>> +					    raw_strategies, &commands, autosquash);
>>  		break;
>>  	case SKIP: {
>>  		struct string_list merge_rr = STRING_LIST_INIT_DUP;
>> @@ -262,11 +268,12 @@ int cmd_rebase__interactive(int argc, const char **argv, const char *prefix)
>>  		ret = rearrange_squash(the_repository);
>>  		break;
>>  	case ADD_EXEC:
>> -		ret = sequencer_add_exec_commands(the_repository, cmd);
>> +		ret = sequencer_add_exec_commands(the_repository, &commands);
>>  		break;
>>  	default:
>>  		BUG("invalid command '%d'", command);
>>  	}
> 
> Before freeing the string list it would be good to reset the number of
> items with commands.nr++ (with a comment explaining why) so the NUL in
> the last item gets freed.
> 
>> +	string_list_clear(&commands, 1);
> 
> As we don't use item.util I think the second argument would be better as 0.
> 
>>  	return !!ret;
>>  }

FWIW I just stumbled across string_list_remove_empty_items(), which
seems to do exactly the same thing, but that way we don’t have to do
this kind of hacks.

>> diff --git a/sequencer.c b/sequencer.c
>> index 99e12c751e..82ca3432cd 100644
>> --- a/sequencer.c
>> +++ b/sequencer.c
>> @@ -4505,21 +4505,27 @@ int sequencer_make_script(struct repository *r, FILE *out,
>>   * Add commands after pick and (series of) squash/fixup commands
>>   * in the todo list.
>>   */
>> -int sequencer_add_exec_commands(struct repository *r,
>> -				const char *commands)
>> +static void todo_list_add_exec_commands(struct todo_list *todo_list,
>> +					struct string_list *commands)
>>  {
>> -	const char *todo_file = rebase_path_todo();
>> -	struct todo_list todo_list = TODO_LIST_INIT;
>> -	struct strbuf *buf = &todo_list.buf;
>> -	size_t offset = 0, commands_len = strlen(commands);
>> -	int i, insert;
>> +	struct strbuf *buf = &todo_list->buf;
>> +	size_t base_offset = buf->len;
>> +	int i, insert, nr = 0, alloc = 0;
>> +	struct todo_item *items = NULL, *base_items = NULL;
>>  
>> -	if (strbuf_read_file(&todo_list.buf, todo_file, 0) < 0)
>> -		return error(_("could not read '%s'."), todo_file);
>> +	base_items = xcalloc(commands->nr, sizeof(struct todo_item));
>> +	for (i = 0; i < commands->nr; i++) {
>> +		size_t command_len = strlen(commands->items[i].string);
>>  
>> -	if (todo_list_parse_insn_buffer(r, todo_list.buf.buf, &todo_list)) {
>> -		todo_list_release(&todo_list);
>> -		return error(_("unusable todo list: '%s'"), todo_file);
>> +		strbuf_addstr(buf, commands->items[i].string);
>> +		strbuf_addch(buf, '\n');
>> +
>> +		base_items[i].command = TODO_EXEC;
>> +		base_items[i].offset_in_buf = base_offset;
>> +		base_items[i].arg_offset = base_offset + strlen("exec ");
>> +		base_items[i].arg_len = command_len - strlen("exec ");
>> +
>> +		base_offset += command_len + 1;
>>  	}
>>  
>>  	/*
>> @@ -4527,39 +4533,60 @@ int sequencer_add_exec_commands(struct repository *r,
>>  	 * are considered part of the pick, so we insert the commands *after*
>>  	 * those chains if there are any.
>>  	 */
>> -	insert = -1;
>> -	for (i = 0; i < todo_list.nr; i++) {
>> -		enum todo_command command = todo_list.items[i].command;
>> -
>> -		if (insert >= 0) {
>> -			/* skip fixup/squash chains */
>> -			if (command == TODO_COMMENT)
>> -				continue;
>> -			else if (is_fixup(command)) {
>> -				insert = i + 1;
>> -				continue;
>> -			}
>> -			strbuf_insert(buf,
>> -				      todo_list.items[insert].offset_in_buf +
>> -				      offset, commands, commands_len);
>> -			offset += commands_len;
>> -			insert = -1;
> 
> I like the simplification of using insert as a flag. Perhaps we should
> document the assumptions. Maybe something like
> 
> We insert the exec commands immediately after rearranging any fixups and
> before the user edits the list. This means that a fixup chain can never
> contain comments (any comments are empty picks that have been commented
> out the the user did not specify --keep-empty) and so it is safe to
> insert the exec command without looking at the command following the
> comment.
> 

I slightly reworded this and added it to the existing comment just
before the for loop:

	/*
	 * Insert <commands> after every pick. Here, fixup/squash chains
	 * are considered part of the pick, so we insert the commands *after*
	 * those chains if there are any.
	 *
	 * As we insert the exec commands immediatly after rearranging
	 * any fixups and before the user edits the list, a fixup chain
	 * can never contain comments (any comments are empty picks that
	 * have been commented out because the user did not specify
	 * --keep-empty).  So, it is safe to insert an exec command
	 * without looking at the command following a comment.
	 */

>> +	insert = 0;
>> +	for (i = 0; i < todo_list->nr; i++) {
>> +		enum todo_command command = todo_list->items[i].command;
>> +		if (insert && !is_fixup(command)) {
>> +			ALLOC_GROW(items, nr + commands->nr, alloc);
>> +			COPY_ARRAY(items + nr, base_items, commands->nr);
>> +			nr += commands->nr;
>> +
>> +			insert = 0;
>>  		}
>>  
>> -		if (command == TODO_PICK || command == TODO_MERGE)
>> -			insert = i + 1;
>> +		ALLOC_GROW(items, nr + 1, alloc);
>> +		items[nr++] = todo_list->items[i];
>> +
>> +		if (command == TODO_PICK || command == TODO_MERGE || is_fixup(command))
> 
> I'm not sure what the is_fixup() is for, if the command is a fixup then
> it will have been preceded by a pick or merge so insert will already be 1
> 
> I feel a bit mean suggesting a reroll when we're on v7 already but I
> think these clean-ups would improve the maintainability of the code.
> I'll take a look at the rest of the changes to this series sometime this
> week.
> 
> Best Wishes
> 
> Phillip
> 

Cheers,
Alban