Hi, Jeremy! On Jul 19, Jeremy Cole wrote: > > 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: > > 1. Some instrumented functions are called only from non-instrumented > functions. > 2. Some instrumented functions are called only from non-returning > functions, such as abort or die functions. > 3. Some instrumented functions are called from functions who call my_end > or my_thread_end (making cs unavailable) before returning. > > In any case please see the attached DRAFT patch for a full implementation > of the idea. Note one bit of ugliness is that non-returning functions, > after this patch, must be marked explicitly as DBUG_ENTER_NO_RETURN -- this > actually is not really a bad thing, though in and of itself.
Thanks, Jeremy! I kind of liked the idea. Although I, probably, wouldn't use DBUG_ENTER_NO_RETURN, but a separate macro DBUG_NO_RETURN that would use your guard variable without calling _db_return_. Hmm, come to think of it, perhaps functions that don't return should still use DBUG_LEAVE? Then no special new macro is needed at all. But what made me thinking was, that this patch only detects whether the function has at least one DBUG_RETURN, anywhere in the function body (your changeset comment mentions this, albeit in a wrong place, so it's a bit confusing). In my experience a notably more popular mistake is to miss DBUG_RETURN only somewhere in a function, like in the early return on the error. What could we do to solve this too? Is C++ class the best we could have? Regards, Sergei _______________________________________________ Mailing list: https://launchpad.net/~maria-developers Post to : [email protected] Unsubscribe : https://launchpad.net/~maria-developers More help : https://help.launchpad.net/ListHelp
