Issue

Attempting to install tarballed extensions that contain paths with more than 100 characters will result in paths being truncated. The original TAR format only supports paths up to 100 characters source.

How to test

I've put a test archive here. The archive contains the following path:

admin/plugins/vmpayment/amazon/library/OffAmazonPaymentsService/OffAmazonPaymentsService.config.inc.php

Test it by using Extensions > Extension Manager > upload the archive and click on Upload & Install. You'll see a blank page (the installer script is meant to die so that the archive is extracted to your tmp directory). Navigate to the tmp directory and look for an install_<random_hash> folder. Look at its contents - the OffAmazonPaymentsService.config.inc.php filename will be truncated since it exceeds the 100 limit.

Workaround

In what seems to be a PAX implementation of tar, there's an 'L' flag that can be set so that the file name will reside in the contents block and the contents of the actual file are in the next block. This allows for longer paths to be stored. source 1 source 2

If you want to test for yourself, you can create a tar archive using 7-Zip which produces this type of archives.

The PR addresses this issue and properly extracts the archive contents (perhaps there are other implementations of TAR long filenames, but I haven't found anything conclusive).