[SVN-1706] Directory representations should be sorted to be diff'able

• Type: Improvement
• Status: Closed
• Priority: Critical
• Resolution: Invalid
• Affects Version/s: all
• Fix Version/s: unscheduled
• Component/s: libsvn_fs_base
• Assignee: Unassigned
• Reporter: Subversion Importer
• Created: 18/Jan/04 16:35
• Updated: 05/Oct/05 16:48
• Resolved: 05/Oct/05 16:48

Description

Directories are duplicated as fulltext many times in the repository.  They
usually remain fulltext during deltification, because the order of entries
changes a lot between revisions, making the svndiff even larger.

The reason should be that libsvn_fs/dag.c/set_entry() uses a hash table during
reading and writing the directory "skels", so the order is not preserved.

In this particular case I think it is better not to use a hash table --- since
only one entry is changed, an unsorted linear array works good enough.  Of
course, code like svn_fs__parse_entries_skel() would then have to be duplicated.

Another way is to sort the entries during deltification.

I currently use 0.35.1, but since nothing about the problem is mentioned on the
0.36 release notes, I'll assume this problem has been unchanged.

Original issue reported by r6144