On 12/13/21 21:56, Mike Frysinger wrote:
for automake, the limitations in the default v7 catch people off guard (like filename limits).
This is a good reason to switch formats. That being said, a downside of --format=pax is that it gratuitously uses pax extensions when not needed by the uses of 'tar' that we're talking about. These pax extensions can cause trouble, as illustrated by Michał's analysis.
This discussion suggests the need for a new, easy-to use format option, which is like '-Hpax' except that it omits atime and ctime, and omits the subseconds part of mtime. Using this format would mean that pax extensions won't be used unless they're needed (a file with a long name, a timestamp past the year 2246, etc.) and so the tarball would be more portable to platforms with older or buggy tarball extractors.
Maybe we could call this the 'art' format, for "archive reproducible tarball", so that people could use 'tar -Hart' for it. Like 'ustar', 'art' format would be a strict subset of 'pax' format so it would be POSIX-conforming.
We could introduce the new option in the next release of GNU tar, and think about changing the default format to it in a later release.
What do you think?
