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Due to the weapon cycle changes done in 4.0 Beta 5, GetSecondaryShipWeapon() can now return nil in cases where previously you could rely on it not returning nil.
If the player shoots all his missiles and then cycles the missile type, GetSecondaryShipWeapon() will now return nil, while previously it returned information about the depleted missile type. Therefore, better make sure to check the return value prior to referencing it.
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