Non-obvious behavior of 'svn merge' when using old repository

[Alexey Neyman <st...@att.net>]

Hi all,

I have just stumbled over a not user-friendly behavior of 'svn merge'. The 
environment was:

- server running 1.6.11
- repository has been created under 1.4.2 and has not been run through 
'svnadmin upgrade' since
- client 1.6.6

When attempting to sync up a branch with latest trunk changes, 'svn merge' 
attempted to bring over ALL revisions of trunk, even those before the 
branchpoint. This, obviously, failed with a lot of tree conflicts.

$ svn merge ^/trunk
--- Merging r2 through r578 into '.':

I finally figured out that this is due to outdated repository version. 
However, shouldn't svn provide some warning in this case to indicate that it 
were not able to determine which revisions need to be merged?

Note that 'svn merge --reintegrate' detects this condition and emit the 
warning:

$ svn merge --reintegrate ^/branches/<branch-name>
svn: Retrieval of mergeinfo unsupported by '<repository>'

Shouldn't regular 'svn merge' do the same?

I am not sure if it was fixed in more recent versions of Subversion.

Regards,
Alexey.