Subject: Re: [GSoC][PATCH v2 5/6] rebase -i: support --ignore-date

From: Junio C Hamano <[email-masked]>
Date: Tue, 13 Aug 2019 10:21:26 -0700

Phillip Wood <[email-masked]> writes:

>> +static void push_dates(struct child_process *child)
>> +{
>> +	time_t now = time(NULL);
>> +	struct strbuf date = STRBUF_INIT;
>> +
>> +	strbuf_addf(&date, "@%"PRIuMAX, (uintmax_t)now);
>> +	argv_array_pushf(&child->args, "--date=%s", date.buf);
>
> it doesn't matter but it might have been nicer to set both dates the
> same way in the environment.
> +	argv_array_pushf(&child->env_array, "GIT_COMMITTER_DATE=%s", date.buf);

We can see that this date string lacks timezone information, which
would likely fall back to whatever timezone the user is in.  Is that
what we want?  I am guessing it is, as we are dealing with "now"
timestamp, but wanted to double check.

>> +			if (opts->ignore_date) {
>> +				if (!author)
>> +					BUG("ignore-date can only be used with "
>> +					    "rebase, which must set the author "
>> +					    "before committing the tree");
>> +				ignore_author_date(&author);
>
> Is this leaking the old author? I'd rather see
>
> 	tmp_author = ignore_author_date(author);
> 	free(author);
> 	author = tmp_author;

Or make sure ignore_author_date() does not leak the original, when
it rewrites its parameter.

But I have a larger question at the higher design level.  Why are we
passing a single string "author" around, instead of parsed and split
fields, like <name, email, timestamp, tz> tuple?  That would allow us
to replace only the time part a lot more easily.  Would it make the
other parts of the code more cumbersome (I didn't check---and if
that is the case, then that is a valid reason why we want to stick
to the current "a single string 'author' keeps the necessary info
for the 4-tuple" design).

>> +			}
>>   			res = commit_tree(msg.buf, msg.len, cache_tree_oid,
>>   					  NULL, &root_commit, author,
>>   					  opts->gpg_sign);
>> +		}
>>     		strbuf_release(&msg);
>>   		strbuf_release(&script);
>> @@ -1053,6 +1087,8 @@ static int run_git_commit(struct repository *r,
>>   		argv_array_push(&cmd.args, "--amend");
>>   	if (opts->gpg_sign)
>>   		argv_array_pushf(&cmd.args, "-S%s", opts->gpg_sign);
>> +	if (opts->ignore_date)
>> +		push_dates(&cmd);
>>   	if (defmsg)
>>   		argv_array_pushl(&cmd.args, "-F", defmsg, NULL);
>>   	else if (!(flags & EDIT_MSG))
>> @@ -1515,6 +1551,11 @@ static int try_to_commit(struct repository *r,
>>     	reset_ident_date();
>>   +	if (opts->ignore_date) {
>> +		ignore_author_date(&author);
>> +		free(author_to_free);
>
> Where is author_to_free set? We should always free the old author, see
> above.

Or require callers to pass a free()able memory to ignore_author_date()
and have the callee free the original?