From: Nguyen Thai Ngoc Duy Date: Tue, 06 Dec 2011 06:23:00 GMT Subject: Re: Suggestion on hashing Message-ID: In-Reply-To: <1323151347.1745.73.camel@yos> On Tue, Dec 6, 2011 at 1:02 PM, Bill Zaumen wrote: > On Tue, 2011-12-06 at 11:46 +0700, Nguyen Thai Ngoc Duy wrote: >> On Tue, Dec 6, 2011 at 8:56 AM, Chris West (Faux) wrote: >> > >> > Nguyen Thai Ngoc Duy wrote: >> >> >> >> SHA-1 charateristics (like 20 byte length) are hard coded everywhere >> >> in git, it'd be a big audit. >> > >> > >> > I was planning to look at this anyway.  My branch[1] allows >> >  init/add/commit with SHA-256, SHA-512 and all the SHA-3 candidates. >> >> Great! > > If you are replacing SHA-1 as an object ID with another hash function, > two things to watch are submodules and alternative object databases. > Because of those, it is necessary to worry about the order in which > repositories are converted.  In the worst case for submodules, you'd > have to do multiple repositories at the same time, switching between > them depending on what you need at each point. I know migration would be painful. But note that new repos can benefit stronger digest without legacy (of course until it links to an old repo). For submodules, I think we should extend it to become something similar to soft-link: git link is an SHA-1 to a text file that contains SHA-1 and maybe other digests of the submodule's tip. -- Duy