Fix crash when attempting to dow-cast nullptr in debug builds
#315
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egiurleo
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nullptr check during downcastnullptr check during ENFORCE in downcast
amomchilov
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nullptr check during ENFORCE in downcastnullptr in debug builds
In our `downcast` helper, we check that the node argument is actually a Prism node. However, doing this requires us to check the `type` field, which will fail if the node is a `nullptr`. By doing a `nullptr` check in the `ENFORCE`, we guarantee we won't crash by checking for a field on a `nullptr`. Co-authored-by: Alex Momchilov <[email protected]>
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st0012
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Oct 31, 2024
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Motivation
In our debug builds, our
down_casthelper verifies that the pointed-to node actually is the kind of node we're trying to cast it to. Doing this requires us to check thetypefield, which will fail if givennullptr.We modify the
ENFORCEcheck to either:nullptrThis is safe because of the short-circuiting behaviour of
||.Test plan
Automated tests continue to pass