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[209.85.221.175]) by smtp.gmail.com with ESMTPSA id a1e0cc1a2514c-860ab71683csm9134241.34.2024.12.13.11.41.29 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 13 Dec 2024 11:41:29 -0800 (PST) Received: by mail-vk1-f175.google.com with SMTP id 71dfb90a1353d-5187f6f7bcaso568486e0c.3; Fri, 13 Dec 2024 11:41:29 -0800 (PST) X-Forwarded-Encrypted: i=1; AJvYcCVdrqF02k7dB2jqHrlU6h4Y3Wh5Sj/DkJc8XEfmdH/IsA30Kt/AVAVgR9mnM3uTIrNANp67Rzl6AJU=@vger.kernel.org, AJvYcCVxeJf3PpGKIQrecpYuQZ911/cXI8KXUwLFE7tWXsF41oSla6bGX0yGJmYEJi6Yufcfk01k+huH8KUi@vger.kernel.org, AJvYcCX4+/fbcBQNy+KUnXD9xzyOgo+tEojo6ONUC18DiCxJ7Uomx/STtC9OG2xuAg/B9wAIJNDs4uPixwIzh7YL@vger.kernel.org X-Received: by 2002:a05:6122:3290:b0:517:4fb0:74bc with SMTP id 71dfb90a1353d-518ca369a45mr5040949e0c.3.1734118889186; Fri, 13 Dec 2024 11:41:29 -0800 (PST) Precedence: bulk X-Mailing-List: workflows@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <46b320b91b8d86fade3c1b1c72ef94da85b45d0d.1733421037.git.geert+renesas@glider.be> In-Reply-To: From: Geert Uytterhoeven Date: Fri, 13 Dec 2024 20:41:17 +0100 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v2 2/2] Increase minimum git commit ID abbreviation to 16 characters To: Linus Torvalds Cc: Dwaipayan Ray , Lukas Bulwahn , Joe Perches , Jonathan Corbet , Thorsten Leemhuis , Andy Whitcroft , =?UTF-8?Q?Niklas_S=C3=B6derlund?= , Simon Horman , Conor Dooley , Miguel Ojeda , Junio C Hamano , workflows@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Hi Linus, On Thu, Dec 5, 2024 at 8:19=E2=80=AFPM Linus Torvalds wrote: > On Thu, 5 Dec 2024 at 10:16, Geert Uytterhoeven = wrote: > > Hence according to the Birthday Paradox, collisions of 12-chararacter > > git commit IDs are imminent, or already happening. > > Note that ambiguous commit IDs are not even remotely as scary as this imp= lies. > > Yes, the current kernel tree has over ten million objects, and when > you look at stable trees etc, you can easily see more. > > But commits are only a fraction (about 1/8th) of the total objects. My > tree is at about 1.3M commits, so we're basically an order of > magnitude off the point where collisions start being an issue wrt > commit IDs. > > Can you find collisions by looking at all objects? Yes. Git will do > that for you, and tell you their types. But to take one recent > example, let's do the 6.12 commit: > adc218676eef25575469234709c2d87185ca223a. To get an ambiguous ID, you > have to go down to 6 characters, and even then git will tell you > there's only one object that is a commit, ie > > $ git show adc218 > > results in > > error: short object ID adc218 is ambiguous > hint: The candidates are: > hint: adc218676eef commit 2024-11-17 - Linux 6.12 > hint: adc2184009c5 blob > > so right now you have a collision in six digits for that commit, but > even then it's actually still entirely unambiguous once you know > you're talking about a commit. That's true for the basic command line tools... > Make the tools deal with the cases we already have, and you'll find > that the shortening is a complete non-issue. FTR, cgit can use some improvements, as https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?= id=3Dadc218 just tells you "Bad object id: adc218". Gr{oetje,eeting}s, Geert --=20 Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k= .org In personal conversations with technical people, I call myself a hacker. Bu= t when I'm talking to journalists I just say "programmer" or something like t= hat. -- Linus Torvalds