mirror of
https://git.savannah.gnu.org/git/tar.git
synced 2026-06-04 06:12:36 +00:00
b960c38c4b
1296 prevented incremental backups on individual files from working, as reported by Andreas Schuldei <andreas@schuldei.org>. This is due to the condition (0 < top_level || !incremental_option) Removing it makes incremental backups work for individual files as well as for directories. On the other hand, it does not affect other functionality, as shown by the reasoning below: To begin with, the two parts of this condition are mutually superfluous, because 1) when top_level < 0, incremental_option == 1 so the condition yields false 2) when top_level >= 0, incremental_option == 0 so the condition yields true. In other words, it is completely equivalent to (!incremental_option) Now, let's consider the effect of its removal. There are two cases: 1) when incremental_option==1 This means incremental backup in progress. In this case dump_file is invoked only for directories or for files marked with 'Y' by get_directory_contents. The latter are those that did not meet the condition in incremen.c:242, which is exactly the same condition as this at create.c:1296. So, for these files the check (!incremental_option) is useless, since the rest of the conditional will yield false anyway. On the other hand, if dump_file is invoked on a directory, the conditional will yield false due to !S_ISDIR assertion, so these will be processed as usual. Thus, for this case the extra condition (!incremental_option) is irrelevant, and its removal won't alter the behavior of tar, *except* that it will enable incremental backups on individual files, which is the wanted effect. 2) when incremental_option==0 In this case the condition yields true and its removal does not affect the functionality.