DSC - Investigate Alternate Tar Mechanism

As part of PUP-5994, we uncovered an issue in PMT that prevents modules with long file names to extract properly with tarballs created in the regular module pipeline / release process.

While we have fixed the issue with PMT, we think that it's possible for tarballs created with a different format to extract properly, given a tarball created with 7zip extracts properly without the code change to PMT. The format can be changed with a command line switch to GNU tar - and we'd like to make this change during publishing to support old agents.

Supported formats include:

• gnu - unlimited filename
• oldgnu - unlimited filename
• v7 - filename limited to 99 chars
• ustar - filename limited to 256 chars
• posix - unlimited filename
• star (gnu tar cannot produce this format)
• pax - produced by git archive

LibArchive seems to have a good understanding of these formats from what I can tell, so maybe that can be used to figure out which tar format extracts without the patch from PUP-5994.

GNU also maintains a page about making tar archives more portable

/cc morgan