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List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: guix-devel-bounces+larch=yhetil.org@gnu.org Sender: "Guix-devel" X-Migadu-Flow: FLOW_IN X-Migadu-Country: US ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=yhetil.org; s=key1; t=1641237534; h=from:from:sender:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:list-id:list-help: list-unsubscribe:list-subscribe:list-post:dkim-signature; bh=95TvmOcxQSd6rov4+ezax0+Bmp2TW0ZlFWB5WSH3uRg=; b=snRbGx2ffmbOCymXIOkGG8V8LWpc0Ht801Nh2S2LCz02DOWmJYHFy9YvpyiECgXTkx56Dh 77PFwBWFD+YvE8cgJ9ay8ZrfCqsgXdKzHxGGWQumJCUR/Tddo3Q7m1RqjAdv9hlObhFhFF lJPgQ+4Xr3Jt3BzHKnCe9cArmCZMRxAaMWFrDiX397jaGkIb3J21Wr7po4oRGjyUmpUSDG /dRAvOGvdLGbRXZADfTv1fhO2FUMya7C21Tlbqo2dPgQaHL6/yZPKW4Rq3J1bzxqhXVdLa TkEkTiwIO3reT5SL6bvR2VEk8vy8FN5IG1LeUbV+khbcAz9+zZBgdXAKx1iQQw== ARC-Seal: i=1; s=key1; d=yhetil.org; t=1641237534; a=rsa-sha256; cv=none; b=mYytRfuWxmmoZHsnF7b2g5j4PWs/uNFlzrDaHK+X2bNfB0UarZ6CCYJWWvZ5jsCWZb28kf ZAhnZjGK60+QJfnPll0BueQ3brW4SwAGQVZ4hWmWudNMmk9XQRonxRfPmu8R01slIkp65W oisH018S4SA7GXp2jgQF9fd+jM2VPXdvh1n1HfZ5cteER4L9stefTMr3GoG/2L3HlTNRB1 zyOw3bYElsFjufUNbvTLo7M6z9htk+GBDRVzpJaWkKBmp66jKBgyfw39idqx7FrSVRK68s iWDKAF5kmVesAz58knOeYvnOd/SHqYf2dE7aY6c8SVW5myAcqD21/7eyYP8tlg== ARC-Authentication-Results: i=1; aspmx1.migadu.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=EEDjiOmE; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (aspmx1.migadu.com: domain of "guix-devel-bounces+larch=yhetil.org@gnu.org" designates 209.51.188.17 as permitted sender) smtp.mailfrom="guix-devel-bounces+larch=yhetil.org@gnu.org" X-Migadu-Spam-Score: -9.59 Authentication-Results: aspmx1.migadu.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=EEDjiOmE; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (aspmx1.migadu.com: domain of "guix-devel-bounces+larch=yhetil.org@gnu.org" designates 209.51.188.17 as permitted sender) smtp.mailfrom="guix-devel-bounces+larch=yhetil.org@gnu.org" X-Migadu-Queue-Id: E2D41362B8 X-Spam-Score: -9.59 X-Migadu-Scanner: scn0.migadu.com X-TUID: 1OFAaz6P6mc+ Hi Liliana, On Mon, 03 Jan 2022 at 19:13, Liliana Marie Prikler wrote: > Am Montag, dem 03.01.2022 um 10:22 +0100 schrieb zimoun: >> On Sun, 02 Jan 2022 at 22:35, Liliana Marie Prikler >> wrote: >>=20 >> > > The statement still appears to me wrong because Git commit hash >> > > only depends on the content itself. >> >=20 >> > If you define content through the NAR hash used by Guix, I'm pretty >> > sure vanity commits invalidate that statement. >>=20 >> I do not understand what it means =E2=80=93 not to say I think your comm= ent >> does not make sense at all.=C2=A0 Well, I already took the time to expla= in >> twice how it works. >>=20 >> >> > Nothing agains Yhetil, but that page did break for me yesterday with a > 502. If you have anything important to say, (partially) quoting > yourself would be much preferred while still adding said link for > curious outsiders, because then I can use an intrinsic lookup mechanism > using only my own mailbox rather than an extrinsic one. This is somehow intrinsic* because public-inbox uses Message-ID as URL. Therefore, using emacs-notmuch, you just have to search for id:86y243kdoo.fsf@gmail.com for instance. *intrinsic: no it is not intrinsic but self-contained. :-) > Anyway, the point here is a rather simple one that you can base on your > own explanations. Due to the different ways Guix and Git filter, > serialize and hash content, you can have two objects O and O', such > that Git hashes O and O' differently, but Guix does not, and similarly > two objects O and O' such that Guix hashes them differently, but Git > does not. Finding particular values for O and O' would in some cases > be computationally expensive, especially if you want to force a hash > collision in SHA-256 instead of reusing the same files but attaching a > different commit message, but theoretically possible, and if theoretic > possibilities is something you want to base your policies on, that is a > thing to consider. Collision with hashing functions does not mean that the hash does not *only* depend on the content. Collision means that 2 contents provides the same hash. The final hashes only depends on the content, whatever the serializer is and as weak as the hashing function is. > I'm not trying to stoke fear, I'm arguing that "raw string in reference> for robustness" is a bad take for a multitude of reasons. 1) No one is advocating to replace tomorrow all by =E2=80=9CGit SHA-1 commit hash in =E2=80=9D. Instead, people exposed what are the motivations to do so, what it would fix, and so on. 2) I am still failing to understand your multitude bad reasons. Yes for sure, introducing more intrinsic values is not straightforward, socially and about toolings, but I have not read multitude fundamentally bad reasons. Anyway. Cheers, simon