Checkout a 1.6 working copy. Delete one of the text-bases. Upgrade to 1.7. The
upgrade doesn't report any problems although it adds a file without a checksum.
A subsequent update that attempts to modify the file with a missing checksum
will assert:
svn: E235000: In file '../src-1.7/subversion/libsvn_wc/wc_db_pristine.c' line
228: assertion failed (sha1_checksum != NULL)
The upgrade should at the very least report the problem to the user. Perhaps the
upgrade should fail? Perhaps the upgrade should insert a not-present node
instead of a normal node?