From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from chiark.greenend.org.uk (permutation-city.chiark.greenend.org.uk [93.93.131.194]) (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 CAB05346A1D for ; Mon, 20 Apr 2026 09:57:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=93.93.131.194 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776679048; cv=none; b=G1obiLGq07WuZVHMbRvnBx66nXL9Q8ld9by1Es3X4n/wrsT6o3ktfJogeCAS5bDyCqtY9WQT13S2IWyEUQQrgxzlcCdL5YwRfOl1cN6UdKnuX6bYgg2/FKEMRUKyFKOlolMcjgE+SXGl0cChmu7N7VLpoPT6e0sYc4ht0qAQGYM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776679048; c=relaxed/simple; bh=iXLfnUtdR9AVEc5NPygsv7cRqhxz0Cf4MbnVj0I3V4Q=; h=From:MIME-Version:Content-Type:Message-ID:Date:To:CC:Subject: In-Reply-To:References; b=X+f1tva9aY98mxn9V7GbW/PvE3tX5KgYwQB/IGtWEuNW17vs6yrn3x5zNIlqEx0x87o+8nsxGJPMNc1RIi/u/h+IimLFq6EFjZB6xbC4hGUFezfSmuaKenuUO/4xv1ozIoJL4/mM1DzeQiI7EW+W4xNHCoY7mXnQg0F1cum6OlI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=chiark.greenend.org.uk; spf=none smtp.mailfrom=chiark.greenend.org.uk; dkim=pass (2048-bit key) header.d=chiark.greenend.org.uk header.i=@chiark.greenend.org.uk header.b=P3LflKtx; arc=none smtp.client-ip=93.93.131.194 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=chiark.greenend.org.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=chiark.greenend.org.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=chiark.greenend.org.uk header.i=@chiark.greenend.org.uk header.b="P3LflKtx" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=chiark.greenend.org.uk; s=k.chiark; h=DKIM-Signature-Warning:References: In-Reply-To:Subject:CC:To:Date:Message-ID:Content-Transfer-Encoding: Content-Type:MIME-Version:From:Sender:Reply-To:Content-ID:Content-Description :Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Id:List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner: List-Archive; bh=v1kuHroWNwB0+GF6xes8zLCTuyRuwsakfExPveEhpck=; b=P3LflKtxr1n+ ywLO6ouMtsXwG3vwTLMor/uA5h9P8mRS2Ch08gLEGXzy4D4kGRm6IoIHqKT2+uG9mFJQoHB6HQM3/ Y+SAMyKKXRbV4bAvXKwFnPabnMgUNC/TpCbxVwK+vFNhHf9fnyigHScKkRARjDgkKK71gZW9bumUi 6LA/Xm3Xtu4LVw2o9Ab/KLn5SCB8HK3aB4POKlDYyTt52TUzop97dHkldK/BNDnCbTgMIEdO8BSDy ZObtLXyjTzD8EHbS13JEJDQBtsx4iivvfYM4uu61cMXlK0SryO8m7DRIW5HWlgFbo8RfOHv+BpSeR WqEPU7b8XDtfAvCAdHjsuw==; Received: by chiark.greenend.org.uk (Debian Exim 4.94.2 #2) with local (return-path ijackson@chiark.greenend.org.uk) id 1wElNb-0006Ds-4r; Mon, 20 Apr 2026 10:57:23 +0100 From: Ian Jackson Precedence: bulk X-Mailing-List: git@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <27109.63619.90318.366157@chiark.greenend.org.uk> Date: Mon, 20 Apr 2026 10:57:23 +0100 To: Colin Stagner CC: git@vger.kernel.org, Christian Heusel , george@mail.dietrich.pub, Christian Hesse , Phillip Wood , Junio C Hamano Subject: Re: [PATCH v2 0/3] contrib/subtree: reduce recursion during split In-Reply-To: <27109.13129.424068.382997@chiark.greenend.org.uk> References: <20260215201748.889866-1-ask+git@howdoi.land> <20260305-cs-subtree-split-recursion-v2-0-7266be870ba9@howdoi.land> <27104.58166.993109.63505@chiark.greenend.org.uk> <27109.13129.424068.382997@chiark.greenend.org.uk> X-Mailer: VM 8.2.0b under 27.1 (x86_64-pc-linux-gnu) DKIM-Signature-Warning: NOTE REGARDING DKIM KEY COMPROMISE https://www.chiark.greenend.org.uk/dkim-rotate/README.txt https://www.chiark.greenend.org.uk/dkim-rotate/67/6720eae2c8ba1e796437a231277957ec.pem Ian Jackson writes ("Re: [PATCH v2 0/3] contrib/subtree: reduce recursion during split"): > Algorithm > > I don't think it is going to be possible to precisely reproduce the > output of the existing git-subtree split. Indeed the existing > git-subtree split is a bit cavalier with metadata (eg `committer` [1]) > which probably ought to be changed in any case. > > Even so, it should be possible to avoid foolishly rewriting the whole > history of the subtree, since we can stop at all the merges made by > "git-subtree merge", which are easily detectable by the extra metadata > keyword fields in the commit message. This last part turns out to be false. It is only `git-subtree add` that puts this metadata in the commit message; `git-subtree merge` doesn't. This makes it very hard to distinguish a subtree merge from (say) a merge of a branch that predates the subtree add. I need to think about this some more but I doubt this can be made to work well without more significant changes, including to the data model. There would have to be some kind of compatibility arrangement to handle existing histories. Colin, is that OK with you? If you would prefer, I could choose a different name for the resulting program. My preference would be, with your consent, to continue to call it "git-subtree", version 2. Regards, Ian. -- Ian Jackson These opinions are my own. Pronouns: they/he. If I emailed you from @fyvzl.net or @evade.org.uk, that is a private address which bypasses my fierce spamfilter.