From: Jonathan Nieder <jrnieder@gmail.com> To: "brian m. carlson" <sandals@crustytoothpaste.net> Cc: git@vger.kernel.org, Duy Nguyen <pclouds@gmail.com> Subject: Re: State of NewHash work, future directions, and discussion Date: Mon, 11 Jun 2018 19:42:52 -0700 [thread overview] Message-ID: <20180612024252.GA141166@aiede.svl.corp.google.com> (raw) In-Reply-To: <20180612022815.GL38834@genre.crustytoothpaste.net> brian m. carlson wrote: > On Mon, Jun 11, 2018 at 12:01:03PM -0700, Jonathan Nieder wrote: >> 1. Hash to be used for command output to the terminal >> 2. Hash used in pack files >> 3. Additional hashes (beyond (2)) that we can look up using the >> translation table >> 4. Additional hashes (beyond (1)) accepted in input from the command >> line and stdin >> >> In principle, (1) and (4) would be globals, and (2) and (3) would be >> tied to the repository. I think this is always what Duy was hinting Here, by 'always' I meant 'also'. Sorry for the confusion. >> at. >> >> All that said, as long as there is some notion of (1) and (4), I'm >> excited. :) Details of how they are laid out in memory are less >> important. > > I'm happy to hear suggestions on how this should or shouldn't work. I'm > seeing these things in my head, but it can be helpful to have feedback > about what people expect out of the code before I spend a bunch of time > writing it. So far you're doing pretty well. :) I just noticed that I have some copy-edits for the hash-function-transition doc from last year that I hadn't sent out yet (oops). I'll send them tonight or tomorrow morning. [...] >> brian m. carlson wrote: >>> The transition plan anticipates a stage 1 where accept only SHA-1 on >>> input and produce only SHA-1 on output, but store in NewHash. As I've >>> worked with our tests, I've realized such an implementation is not >>> entirely possible. We have various tools that expect to accept invalid >>> object IDs, and obviously there's no way to have those continue to work. >> >> Can you give an example? Do you mean commands like "git mktree"? > > I mean situations like git update-index. We allow the user to insert > any old invalid value (and in fact check that the user can do this). > t0000 does this, for example. I think we can forbid this in the new mode (using a test prereq to ensure the relevant tests don't get run). Likewise for the similar functionality in "git mktree" and "git hash-object -w". >> You can always use something like e.g. "doubled SHA-1" as a proof of >> concept, but I agree that it's nice to be able to avoid some churn by >> using an actual hash function that we're likely to switch to. > > I have a hash that I've been using, but redoing the work would be less > enjoyable. I'd rather write the tests only once if I can help it. Thanks for the test fixes so far that make most of the test suite hash-agnostic! For t0000, yeah, there's no way around having to hard-code the new hash there. Thanks, Jonathan
prev parent reply other threads:[~2018-06-12 2:43 UTC|newest] Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-06-09 20:56 brian m. carlson 2018-06-09 21:26 ` Ævar Arnfjörð Bjarmason 2018-06-09 22:49 ` Hash algorithm analysis brian m. carlson 2018-06-11 19:29 ` Jonathan Nieder 2018-06-11 20:20 ` Linus Torvalds 2018-06-11 23:27 ` Ævar Arnfjörð Bjarmason 2018-06-12 0:11 ` David Lang 2018-06-12 0:45 ` Linus Torvalds 2018-06-11 22:35 ` brian m. carlson 2018-06-12 16:21 ` Gilles Van Assche 2018-06-13 23:58 ` brian m. carlson 2018-06-15 10:33 ` Gilles Van Assche 2018-07-20 21:52 ` brian m. carlson 2018-07-21 0:31 ` Jonathan Nieder 2018-07-21 19:52 ` Ævar Arnfjörð Bjarmason 2018-07-21 20:25 ` brian m. carlson 2018-07-21 22:38 ` Johannes Schindelin 2018-07-21 23:09 ` Linus Torvalds 2018-07-21 23:59 ` brian m. carlson 2018-07-22 9:34 ` Eric Deplagne 2018-07-22 14:21 ` brian m. carlson 2018-07-22 14:55 ` Eric Deplagne 2018-07-26 10:05 ` Johannes Schindelin 2018-07-22 15:23 ` Joan Daemen 2018-07-22 18:54 ` Adam Langley 2018-07-26 10:31 ` Johannes Schindelin 2018-07-23 12:40 ` demerphq 2018-07-23 12:48 ` Sitaram Chamarty 2018-07-23 12:55 ` demerphq 2018-07-23 18:23 ` Linus Torvalds 2018-07-23 17:57 ` Stefan Beller 2018-07-23 18:35 ` Jonathan Nieder 2018-07-24 19:01 ` Edward Thomson 2018-07-24 20:31 ` Linus Torvalds 2018-07-24 20:49 ` Jonathan Nieder 2018-07-24 21:13 ` Junio C Hamano 2018-07-24 22:10 ` brian m. carlson 2018-07-30 9:06 ` Johannes Schindelin 2018-07-30 20:01 ` Dan Shumow 2018-08-03 2:57 ` Jonathan Nieder 2018-09-18 15:18 ` Joan Daemen 2018-09-18 15:32 ` Jonathan Nieder 2018-09-18 16:50 ` Linus Torvalds 2018-07-25 8:30 ` [PATCH 0/2] document that NewHash is now SHA-256 Ævar Arnfjörð Bjarmason 2018-07-25 8:30 ` [PATCH 1/2] doc hash-function-transition: note the lack of a changelog Ævar Arnfjörð Bjarmason 2018-07-25 8:30 ` [PATCH 2/2] doc hash-function-transition: pick SHA-256 as NewHash Ævar Arnfjörð Bjarmason 2018-07-25 16:45 ` Junio C Hamano 2018-07-25 17:25 ` Jonathan Nieder 2018-07-25 21:32 ` Junio C Hamano 2018-07-26 13:41 ` [PATCH v2 " Ævar Arnfjörð Bjarmason 2018-08-03 7:20 ` Jonathan Nieder 2018-08-03 16:40 ` Junio C Hamano 2018-08-03 17:01 ` Linus Torvalds 2018-08-03 16:42 ` Linus Torvalds 2018-08-03 17:43 ` Ævar Arnfjörð Bjarmason 2018-08-04 8:52 ` Jonathan Nieder 2018-08-03 17:45 ` brian m. carlson 2018-07-25 22:56 ` [PATCH " brian m. carlson 2018-06-11 21:19 ` Hash algorithm analysis Ævar Arnfjörð Bjarmason 2018-06-21 8:20 ` Johannes Schindelin 2018-06-21 22:39 ` brian m. carlson 2018-06-11 18:09 ` State of NewHash work, future directions, and discussion Duy Nguyen 2018-06-12 1:28 ` brian m. carlson 2018-06-11 19:01 ` Jonathan Nieder 2018-06-12 2:28 ` brian m. carlson 2018-06-12 2:42 ` Jonathan Nieder [this message]
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style List information: http://vger.kernel.org/majordomo-info.html * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20180612024252.GA141166@aiede.svl.corp.google.com \ --to=jrnieder@gmail.com \ --cc=git@vger.kernel.org \ --cc=pclouds@gmail.com \ --cc=sandals@crustytoothpaste.net \ --subject='Re: State of NewHash work, future directions, and discussion' \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: link
Code repositories for project(s) associated with this inbox: https://80x24.org/mirrors/git.git This is a public inbox, see mirroring instructions for how to clone and mirror all data and code used for this inbox; as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).