Laurent Lyaudet <[email protected]> writes:
> Thanks for your nice reply :).
> Indeed, it is surprising that GMail webmail doesn't use In-Reply-To or
> References header then.
>
>> Note that the "Message-ID" for each of his emails is unique. And each
>> message sets the "In-Reply-To" header to the previous message in the
>> thread. That is, "[PATCH 2/4]" sets it's "In-Reply-To" to "[PATCH 1/4]",
>> "[PATCH 3/4]" sets it's "In-Reply-To" to "[PATCH 3/4]", and so on.
> I don't see this when I look at the headers in the webmail:
> All the subsequent emails "[PATCH x/4]" keep the same In-Reply-To and
> References headers:
> In-Reply-To: <[email protected]>
> References: <[email protected]>
> It means that GMail must use the timestamps to determine the order in
> the thread.
> Do you really see
> In-Reply-To: <[email protected]>
> In-Reply-To: <[email protected]>
> ...
> on your side?
> It would mean that something strange happens during the email routing with
> SMTP
> (on the GMail servers? or somewhere in-between?).
Ah your right, my bad:
$ grep -E '^(In-Reply-To|Message-ID):' -- *.eml
Minimize memory [...]:Message-ID:
<[email protected]>
[PATCH 1_4] [...]:Message-ID: <[email protected]>
[PATCH 1_4] [...]:In-Reply-To: <[email protected]>
[PATCH 2_4] [...]:Message-ID: <[email protected]>
[PATCH 2_4] [...]:In-Reply-To: <[email protected]>
[PATCH 3_4] [...]:Message-ID: <[email protected]>
[PATCH 3_4] [...]:In-Reply-To: <[email protected]>
[PATCH 4_4] [...]:Message-ID: <[email protected]>
[PATCH 4_4] [...]:In-Reply-To: <[email protected]>
Basically, here every patch is treated as a reply to the first message
with the subject "Minimize memory". My previous explanation, where each
patch is sent as a reply to a previous patch, can be done using 'git
send-email', though. It looks like it is the "format.thread"
configuration that controls that [1]. It looks like Pádraig is using
"shallow", but the behavior I was describing was for "deep".
Usually, if an email client isn't using Message-IDs to track replies,
then they are using subjects. It probably works for most people who do
not send patches to mailing lists.
Using Message-IDs isn't perfect either. Sometimes people don't subscribe
to a list and want to reply after reading the archives. It is quite easy
to forget to set the Message-ID yourself in that case. I am guilty of
doing it myself, which I then feel bad about since it breaks everyone's
threading. :)
Collin
[1]
https://git-scm.com/docs/git-config#Documentation/git-config.txt-formatthread
