core dump when merging grabs a file not yet in the WD

The session set up in repos_to_wc_copy doesn't have a base_dir.
However, the client tries to use it to write out auth data. 

Don't know how you guys are prioritizing things right now, but it
seems to me to be a P1.

Here is my patch to work around the bug (on rev 3428):

svn diff auth.c
Index: auth.c
===================================================================
--- auth.c
+++ auth.c	2002-10-21 15:57:11.000000000 -0400
@@ -233,6 +233,12 @@
   svn_error_t *err;
   int wc_format;
 
+  if (!cb->base_dir) {
+    /* This was called from a session with no base dir. At least occurs 
+      when called from repos_to_wc_copy. Punt. */
+    return SVN_NO_ERROR;
+  }
+
   /* Repository queries (at the moment HEAD to number, but in future date
      to number and maybe others) prior to a checkout will attempt to
store
      auth info before the working copy exists.  */

Original issue reported by j_palmucci