used to return "" and not bool(false). It's not worth keeping it because
STR_FREE() and zval_dtor() always have to check for it and it slows down
the general case. In addition, it seems that empty_string has been abused
quite a lot, and was used not only for setting zval's but generally in
PHP code instead of "", which wasn't the intention. Last but not least,
nuking empty_string should improve stability as I doubt every place
correctly checked if they are not mistakenly erealloc()'ing it or
calling efree() on it.
NOTE: Some code is probably broken. Each extension maintainer should
check and see that my changes are OK. Also, I haven't had time to touch
PECL yet. Will try and do it tomorrow.
a) When array unserializer encounters less data than it expects (like:
a:1:{}) it crashes. I don't understand exactly why it does, but the fact
is it does. So now it should catch "}" and bail out.
b) When array/object data are serialized, the count is written by hash
count. However, it can be that in-loop check fails and less data than
expected will then be written into the array. Which, due to a), would
crash on unserialize. So now it will write empty entries in place of
entries it cannot serialize (the other choice would be make two passes on
the data, which I don't like).