Discussion of Fossil 2.x continues on the fossil-dev mailing list. I am offering this update to the broader fossil-users community to elicit feedback.
(1) Moving forward, Fossil repositories will be able to name artifacts using either the legacy SHA1 hash or using a SHA3-256 hash. Both hashes can be used within the same repository. Long running projects, such as SQLite, can continue forward without changing any existing hash values yet still use SHA3 names for new content (2) For most display purposes, the 64-digit SHA3-256 hash will be truncated to the same 40-character length as a SHA1 hash. Most users will probably never notice that a hash algorithm change has occurred. The full 256-bit hash will be carried internally for collision detection, and will be accessible on some detailed UI screens. (3) To facility trouble-free upgrades, there will be a simultaneous release of Fossil 2.0 and Fossil 2.1. (4) Fossil 2.0 will be fully compatible with Fossil 1.x. No "fossil rebuild" is needed. Just drop the new executable on your $PATH and continue typing fossil commands just like you always have. Fossil 2.0 will sync and clone with Fossil 1.x and will read and write all the same repository files as Fossil 1.x. The are completely interchangeable. The only difference is that Fossil 2.0 understands SHA3 hashes whereas Fossil 1.x does not. But Fossil 2.0 does not generate any SHA3 artifacts so it will not do anything to confuse Fossil 1.x. (5) Fossil 2.1 is almost identical to Fossil 2.0. The only difference is that Fossil 2.1 always uses SHA3 names for new content. Thus Fossil 2.1 will generate artifacts that Fossil 1.x does not know how to interpret. And Fossil 2.1 will have difficulty syncing with Fossil 1.x. But Fossil 2.0 and Fossil 2.1 will interoperate seamlessly. (6) The upgrade process goes like this: First begin deploying Fossil 2.0 everywhere within the organization. Once Fossil 2.0 is deployed everywhere, then go back and start deploying Fossil 2.1 everywhere. As long as nobody tries to use Fossil 2.1 until after everyone has stopped using Fossil 1.x, no incompatibilities will be occur and everything should continue to operate normally. (7) After Fossil 2.1 is deployed, all new content will use SHA3 hashes exclusively. Older content will continue to be named by the legacy SHA1 hashes so existing hyperlinks and command line arguments will continue to work just as if no hash algorithm change had ever occurred. (8) The above is just a plan. Everything is subject to change. (9) Your feedback is encouraged and appreciated. -- D. Richard Hipp [email protected] _______________________________________________ fossil-users mailing list [email protected] http://lists.fossil-scm.org:8080/cgi-bin/mailman/listinfo/fossil-users
