The function fulfillBasicOrder() of the reference implementation is entirely protected by the reentrancy guard.
However in the production implementation, the call to _triggerIfArmed() isnt protected by the reentrancy guard.
As _triggerIfArmed() does external calls this doesnt seem logical, however the risk seems low.
For comparison: the comparable function_validateAndFulfillAdvancedOrder() is protected end to end by a reentrancy guard, which protects the call to _applyFractionsAndTransferEach() and thus the call to _triggerIfArmed(accumulator);
Context:
ReferenceConsideration.sol#L83-L93, Consideration.sol#L76-L84, BasicOrderFulfiller.sol
Reference code:
Production code:
Do the _clearReentrancyGuard(); after the call to _triggerIfArmed(accumulator);
