Maria developers/captains,
Prior to posing it as a final patch contribution or opening a JIRA
ticket, I wanted to propose this idea.
The attached patch adds what amounts to compile-time checking for
unmatched DBUG_ENTER/DBUG_LEAVE (DBUG_RETURN, DBUG_VOID_RETURN) by
introducing a variable in DBUG_ENTER which is only used in DBUG_LEAVE.
This allows any compiler which can robustly detect unused variables to
detect the mismatch at compile-time. There is already a run-time check
for this case, but it is somewhat limited as it requires _db_return_
to be called in order to detect the mismatch, and this is in practice
not always the case. Particularly three cases allow this to escape
detection:
