From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mout-p-103.mailbox.org (mout-p-103.mailbox.org [80.241.56.161]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A8C3A1A9B2B for ; Thu, 3 Apr 2025 20:31:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=80.241.56.161 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743712283; cv=none; b=lClOjKhuGsGo9BUPn32NR7RuFAqT/2KeodX9YCgSnSQN0pWiXDqZVFrvMU8C6KLIpmIpZoLSTQgNTMpLbsO0WULcVxXANVekouJTQ2vUp9w8h/QzRUPffPzirBlXP4zY3mKtOT3DhiSNur5+GVvlt13SHTKsJ6m9+4CNMMY1Wns= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743712283; c=relaxed/simple; bh=gcJ6S21gn0hbmfCCTjHFYSa41jjIbTmatMYWcfSKqRo=; h=Mime-Version:Content-Type:Date:Message-Id:Cc:Subject:From:To: References:In-Reply-To; b=E5J1PJRalsc2WmjWv48oeK4F+ovtlN6sSCwj3BI9YZ6UpeyTVYVVVw/mjPt5vyxhc8PoV+VFpJiZvULdVKDOxzUcdgZ1FgT0/maxKG4DJ68ellyVlrL6QVGfFux3U4OldkTTFFW4hQke/3/q54SjpyP3VkNvmMDoF12I81xY41U= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=buenzli.dev; spf=pass smtp.mailfrom=buenzli.dev; arc=none smtp.client-ip=80.241.56.161 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=buenzli.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=buenzli.dev Received: from smtp202.mailbox.org (smtp202.mailbox.org [IPv6:2001:67c:2050:b231:465::202]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (No client certificate requested) by mout-p-103.mailbox.org (Postfix) with ESMTPS id 4ZTD0H5XdRz9t4t; Thu, 3 Apr 2025 22:31:11 +0200 (CEST) Precedence: bulk X-Mailing-List: git@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Thu, 03 Apr 2025 22:31:08 +0200 Message-Id: Cc: "Martin von Zweigbergk" , "Git Mailing List" , "Edwin Kempin" , "Scott Chacon" , "philipmetzger@bluewin.ch" Subject: Re: Gerrit, GitButler, and Jujutsu projects collaborating on change-id commit footer From: "Remo Senekowitsch" To: "Theodore Ts'o" , "Elijah Newren" References: <20250403174847.GB3051250@mit.edu> In-Reply-To: <20250403174847.GB3051250@mit.edu> X-Rspamd-Queue-Id: 4ZTD0H5XdRz9t4t On Thu Apr 3, 2025 at 7:48 PM CEST, Theodore Ts'o wrote: > On Thu, Apr 03, 2025 at 08:39:31AM -0700, Elijah Newren wrote: >>=20 >> But isn't unique, right? The whole point of having the >> change ID is to preserve it despite edits (e.g. rebase, commit >> --amend, cherry-pick), meaning that you end up with multiple commits >> with the same . > > It's supposed to be unique, but it isn't always. I've certainly seen > cases where it might not be, but that's arguably a bug. I suspect in > some cases it's because users are cutting and pasting commit > descriptions, and sometimes when they rebase a patch series, patches > will get collapsed or split apart --- especially when backporting to > an older LTS release. > > Perhaps because of this, in some communities, their tooling in front > of Gerrit will always regenerate the Commit-ID when doing a > cherry-pick (For example, when cherry-picking from the development > HEAD branch back to a release branch). > > So as a cauaionary note, as people use Change ID's in Gerrit today, > sometimes the Change ID changes between rebases, and I've certainly > seen cases where the sematic meaning of the commit has changed > significantly without changing the Change ID. So it's great as a > hint, but in practice, at least today, it might not be completely safe > to assume the semantics are as advertised.... That is all true. I would just say that some change-ids not being unique doesn't systematically take away from the benefits. If a given change-id is unique, you get all the benefits for that patch, independent of the uniqueness of the other change-ids. If some patch changes a lot semantically while keeping its change-id, that will degrade its review history, but without affecting the review history of any other patch. Remo