Re: [RFC PATCH] ident: don't cache default date

> Am 18.04.2018 um 19:47 schrieb Phillip Wood:
>> On 18/04/18 12:27, Ævar Arnfjörð Bjarmason wrote:
>>> On Wed, Apr 18 2018, Phillip Wood wrote:
>>>> From: Phillip Wood <phillip.wood@dunelm.org.uk>
>>>> as it is created by running an separate instance of 'git commit'.  If
>>>> the reworded commit is follow by further picks, those later commits
>>>> will have an earlier committer date than the reworded one. This is
>>>> caused by git caching the default date used when GIT_COMMITTER_DATE is
>>>> not set. Fix this by not caching the date.
>>>>
>>>> Users expect commits to have the same author and committer dates when
>>>> the don't explicitly set them. As the date is now updated each time
>>>> git_author_info() or git_committer_info() is run it is possible to end
>>>> up with different author and committer dates. Fix this for
>>>> 'commit-tree', 'notes' and 'merge' by using a single date in
>>>> commit_tree_extended() and passing it explicitly to the new functions
>>>> git_author_info_with_date() and git_committer_info_with_date() when
>>>> neither the author date nor the committer date are explicitly
>>>> set. 'commit' always passes the author date to commit_tree_extended()
>>>> and relied on the date caching to have the same committer and author
>>>> dates when neither was specified. Fix this by setting
>>>> GIT_COMMITTER_DATE to be the same as the author date passed to
>>>> commit_tree_extended().
>>>>
>>>> Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk>
>>>> Reported-by: Johannes Sixt <j6t@kdbg.org>
>>>> ---
>>>>
>>>> I'm slightly nervous that setting GIT_COMMITTER_DATE in
>>>> builtin/commit.c will break someone's hook script. Maybe it would be
>>>> better to add a committer parameter to commit_tree() and
>>>> commit_tree_extended().
> 
> While I like the basic theme of your patch, I think we should fix this
> case in a much simpler way, namely, use the infrastructure that was
> introduced for git-am.
> 
> I've shamelessly lifted the commit message from your patch.

> ---- 8< ----
> Subject: [PATCH] sequencer: reset the committer date before commits
> 
> Now that the sequencer commits without forking when the commit message
> isn't edited all the commits that are picked have the same committer
> date. If a commit is reworded it's committer date will be a later time
> as it is created by running an separate instance of 'git commit'.  If
> the reworded commit is follow by further picks, those later commits
> will have an earlier committer date than the reworded one. This is
> caused by git caching the default date used when GIT_COMMITTER_DATE is
> not set. Reset the cached date before a commit is generated
> in-process.
> 
> Signed-off-by: Johannes Sixt <j6t@kdbg.org>
> ---
>  sequencer.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/sequencer.c b/sequencer.c
> index f9d1001dee..f0bac903a0 100644
> --- a/sequencer.c
> +++ b/sequencer.c
> @@ -1148,6 +1148,8 @@ static int try_to_commit(struct strbuf *msg, const char *author,
>  		goto out;
>  	}
>  
> +	reset_ident_date();
> +
>  	if (commit_tree_extended(msg->buf, msg->len, &tree, parents,
>  				 oid, author, opts->gpg_sign, extra)) {
>  		res = error(_("failed to write commit object"));
>