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** [patches:#555] never send NULL selectors to objects**

**Status:** open **Group:** bugfix **Labels:** puredata-dev crash **Created:** Fri Aug 28, 2015 08:07 PM UTC by IOhannes m zmölnig **Last Updated:** Fri Aug 28, 2015 08:07 PM UTC **Owner:** Miller Puckette

when an object receives bang/float/symbol/pointer messages without having a bang/float/symbol/pointer method defined, it will use the list method instead (if the object has set one).

however, this list method is called with a selector set to 0 (NULL).

if the object passes on the exact incoming message to its outlet (keeping the NULL selector intact), this will lead to a crash, in most cases: -if the downstream object has an `anything` method and accesses the selector name without checking for NULL first (e.g. `[print]` will simply crash because it tries to print the non-existing selector) OR - if the downstream object has no `anything` method, the dispatcher will crash when trying to display the `no method for ...` error

since this means that NULL-selectors are forbidden within Pd, Pd shouldn't emit them intentionally.

attached are two patches: - `0001-never-send-NULL-selectors-to-objects.patch` makes sure that the dispatcher does not generate messages with a NULL-selector. - `0002-gracefully-handle-messages-with-NIL-selector.patch` makes sure that at least the dispatcher does not crash if it encounters a method with a NULL-selector (as generated by some random object).

the first patch is more important.

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