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From: Johannes Sixt <j6t@kdbg.org>
To: Git Mailing List <git@vger.kernel.org>
Cc: Phillip Wood <phillip.wood@dunelm.org.uk>
Subject: How dangerous is --committer-date-is-author-date these days?
Date: Sat, 28 Sep 2024 08:59:57 +0200	[thread overview]
Message-ID: <6af09726-e3bf-4903-87ae-9524ad334678@kdbg.org> (raw)

The option --committer-date-is-author-date of git-rebase rewrites the
committer dates like its name suggests. It is not uncommon that commits
are rearranged and cherry-picked. Then, as a consequence, author dates
are not decreasing when walking back in history. Now, if such a history
with a non-monotonic author date is rebased one final time with
--committer-date-is-author-date, this creates a history with
non-monotonic committer dates. I recall that this is not a good thing to
have since it can confuse our history walker.

- Why do we have --committer-date-is-author-date in a porcelain command?
- Should we remove it?
- Should we require an explicit --force instead of implying it?
- Should we issue a big warning about the consequences?

Here is the discussion that introduced the option git-rebase:
rebase -i: support --committer-date-is-author-date
https://lore.kernel.org/git/20200817174004.92455-4-phillip.wood123@gmail.com/

I am asking this here after I have participated in this Stackoverflow
question, where git rebase --committer-date-is-author-date was suggested
as a solution to "rewrite name and email, but not timestamps".
https://stackoverflow.com/questions/79024409

-- Hannes


             reply	other threads:[~2024-09-28  7:33 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-09-28  6:59 Johannes Sixt [this message]
2024-09-28  9:49 ` How dangerous is --committer-date-is-author-date these days? Phillip Wood
2024-09-28 10:04   ` Phillip Wood
2024-09-30 14:49     ` Kristoffer Haugsbakk
2024-09-30 17:08       ` Junio C Hamano
2025-10-08 20:41       ` SZEDER Gábor
2025-10-08 19:45 ` [PATCH] doc: warn against --committer-date-is-author-date kristofferhaugsbakk
2025-10-09 13:46   ` Phillip Wood
2025-10-09 14:31     ` Kristoffer Haugsbakk
2025-10-09 20:47       ` Kristoffer Haugsbakk
2025-10-09 21:58         ` Junio C Hamano
2025-10-09 22:56           ` Kristoffer Haugsbakk
2025-10-09 21:41     ` Junio C Hamano
2025-10-09 21:57       ` Kristoffer Haugsbakk
2025-10-11  9:15   ` Johannes Sixt
2025-10-16 14:13     ` Kristoffer Haugsbakk
2025-10-16 15:12       ` Kristoffer Haugsbakk
2025-10-16 15:28       ` Johannes Sixt
2025-10-16 15:42         ` Kristoffer Haugsbakk
2025-10-16 16:23         ` Junio C Hamano
2025-11-19 16:27           ` Kristoffer Haugsbakk
2025-11-20 16:26   ` [PATCH v2] " kristofferhaugsbakk
2025-11-20 17:19     ` Johannes Sixt
2025-11-26 16:02     ` Phillip Wood
2025-11-27  6:30       ` Kristoffer Haugsbakk

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