Copy externals when branching

[iprmaster <ip...@gmail.com>]

Hi everybody,

I have a problem on how to handle svn:externals in case of repository branching.

Let suppose I would like to have a repository structure like this:

- repository root
...trunk
......dir1
......dir2
......dirExt1 svn:externals -> https:/path/to/an/external/repository
......dir3
......dirExt2 svn:externals -> https:/path/to/another/external/repository
...tags
......v20090101
.........dir1
.........dir2
.........dirExt1 svn:externals -r12345 -> https:/path/to/an/external/repository
.........etc.
...branches
......ourDev_20090101
.........dir1
.........dir2
.........dirExt1 (??)
.........dir3
.........dirExt2 (??)

My needs can be summarized as follows:

1) in trunk the svn:externals definitions should *always* point the HEAD versions of the external 
repositories -> AFAIK this is automatically done if I define "unversioned" svn:externals

2) in any tag versioned svn:externals definitions have to be set: I have just discovered svncopy.pl, so this is 
not an issue either :D

- now the challenge: if I define a branch (i.e. ourDev_20090101), I would like that some/all svn:externals 
definitions are replaced by actual directories on *our* repository. On other words, once I have branched 
our repository, the development of dirExt1 dirExt2 has to continue on it. However, it would be nice if later 
a merge back to the trunk would be possible ;-)

Vendor branches may represent a solution, but they make more sense if you stick your whole 
development to a stable version of the external libraries (like in the example given in the 
SVN-documentation).

I am wondering it there exists a smarter solution... Do you know one?

Thanks,
Max