transactions: avoid late tear-down (issue641)
We use weak references (ugh) to avoid having to manually delete
transaction references out of each call frame when an exception occurs.
adding he
llo
abort: '\n' and '\r' disallowed in filenames
adding he
llo
abort: '\n' and '\r' disallowed in filenames
adding hell
o
abort: '\n' and '\r' disallowed in filenames
adding hell
o
abort: '\n' and '\r' disallowed in filenames
f he
llo he
llo
f hell
o hell
o