For example, the SVN 1.5 client has one layout for working copies, and the SVN 1.6 client has a different layout. I understand that the layout automatically gets upgraded when it gets touched by a newer client.
If I have a working copy on my system, how can I find out the version of the layout it's using?
If .svn/format exists, then read the number in it:
If .svn/format doesn't exist then the version number is on the first line in .svn/entries:
Subversion 1.6 was the first one not to use .svn/format. Version 7 and older used XML-based .svn/entries file, newer versions use less verbose line-based file format.
Since Subversion 1.7 the version number is stored in the .svn/wc.db SQLite database in the "user_version" field. So even though .svn/format is bumped to version 12 the actual format version is 29 and future versions may not update .svn/format anymore. To obtain the version number from .svn/wc.db there are two methods:
sqlite3 in your path, sqlite3 .svn/wc.db "PRAGMA user_version"sqlite3 in your path, open .svn/wc.db in a hex editor and read the DWORD at offset 0x3cAll the format version numbers are described in wc.h along with the version numbers of respective Subversion releases.