What does it mean for SVN "to pollute the local source tree"?

Question

I'm reading "Professional Team Foundation Server 2010" by Wrox, and in an advantages/disadvantages list, the said:

"Like CVS, SVN makes use of .svn directories inside the source folders to store state of the local working copy, and to allow synchronization with the server. However, it can have the affect of polluting the local source tree, and can cause performance issues wiht very large projects or files."

What does the bit about pollution mean? I've used SVN for C# & ASP.NET projects for a long time and haven't encountered any problems. What probably does this quote think I should have been watching out for?

Answer 1

"Polluting the source tree" is the term they're using to mean that SVN places hidden directories (.svn directories) throughout your source code. The .svn directories contain metadata regarding your checked-out source code. Traditionally, there has been a one-to-one correspondence between a directory in your source code and a corresponding .svn directory. Therefore, bigger source code, more .svn directories.

Actually, SVN 1.7 drastically changes (for the better) how this process works. Now, there is only one .svn directory for your entire working copy. I don't think this "polluting" is a fair criticism any longer.