Auto-props can set a property name that regular 'propset' can't. Example:
[[[
% subversion/svn/svn add \
--config-option 'config:miscellany:enable-auto-props=true' \
--config-option 'config:auto-props:*.t=*.c=bar' \
foo.t
A foo.t
% svn pl -v foo.t
Properties on 'foo.t':
*.c
bar
% svn propset '*.h' baz foo.t
svn: E195011: '*.h' is not a valid Subversion property name
zsh: exit 1 svn propset '*.h' baz foo.t
]]]
It shouldn't be the case that '*.c' can be set and '*.h' can't be set.
See email "Auto-props not validated" from Daniel Shahaf on 2014-04-09, archived
at e.g. <http://svn.haxx.se/dev/archive-2014-04/0143.shtml>.