New template updated ** Description changed:
[Impact] - * An explanation of the effects of the bug on users and + * libzstd v0.5.1 is an experimental version, + which generates and read an experimental format + incompatible with official libzstd v1+ format. - * justification for backporting the fix to the stable release. - - * In addition, it is helpful, but not required, to include an - explanation of how the upload fixes this bug. + * Backporting a newer version >= v1.0, such as artful's v1.3.1, + fixes this issue [Test Case] - * detailed instructions how to reproduce the bug + * download latest upstream zstd source tarball from + https://github.com/facebook/zstd/releases - * these should allow someone who is not familiar with the affected - package to reproduce the bug and verify that the updated package fixes - the problem. + * unpack, compile (make) + + * compress a file with upstream version + + * try to decompress with Ubuntu LTS 16.04 version -> it fails + [Regression Potential] - * discussion of how regressions are most likely to manifest as a result - of this change. + * During transition, if some user switches to newer zstd version, and + then send compressed data to another user has not yet updated zstd, the + receiver will not be able to decompress as long as he does not update. - * It is assumed that any SRU candidate patch is well-tested before - upload and has a low overall risk of regression, but it's important - to make the effort to think about what ''could'' happen in the - event of a regression. + * Note though that newer version contains a compatibility module which + makes it able to read data generated by older versions, such as v0.5.1. + Any existing document compressed with v0.5.1 will still be readable + after update to v1.3.1. - * This both shows the SRU team that the risks have been considered, - and provides guidance to testers in regression-testing the SRU. [Other Info] - - * Anything else you think is useful to include - * Anticipate questions from users, SRU, +1 maintenance, security teams and the Technical Board - * and address these questions in advance + + * Linux kernel 4.14 now integrates zstd compression / decompression, + primarily for BtrFS and SquashFS, with patches available for reiser4, + zram, and initrd. Kernel version does not support compatibility module, + hence cannot read data from v0.5.1. Userland tools associated with these + services will fail if they link to Ubuntu LTS libzstd, as generating + incompatible data. + + * On top of the incompatible format issue, libzstd v0.5.1 API is old + and missing several features that applications relying on libzstd need, + such as streaming interface, or bulk processing for dictionary + compression. --- Original description --- Please backport libzstd 1.3.1+dfsg-1 (universe) from artful to xenial. Reason for the backport: ======================== Current version in Xenial is v0.5.1, it's an experimental version, using its own, incompatible format. As a consequence, zstd on Ubuntu Xenial is not compatible with the rest of the world. This is of important concern for products using libzstd as a shared library : on Ubuntu Xenial, produced data is different, not compatible with v1+. This issue has been made more pressing with the integration of zstd in Linux Kernel, as userland tools must also be updated to read and generate zstd. Note : this request was first improperly filled at : https://bugs.launchpad.net/zesty-backports/+bug/1717037 Testing: ======== Mark off items in the checklist [X] as you test them, but please leave the checklist so that backporters can quickly evaluate the state of testing. Backport available from PPA: https://launchpad.net/~ginggs/+archive/ubuntu/backports * xenial: [X] Package builds without modification (needs debhelper 10) [X] zstd installs cleanly and runs [ ] zstd-dbgsym installs cleanly and runs [ ] libzstd1-dbgsym installs cleanly and runs [X] libzstd-dev installs cleanly and runs [X] libzstd1 installs cleanly and runs No reverse dependencies -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1717040 Title: Please backport libzstd 1.3.1+dfsg-1 (universe) from artful To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/libzstd/+bug/1717040/+subscriptions -- ubuntu-bugs mailing list [email protected] https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
