Are oil price fluctuations a demand shock or a supply shock? This is a very important question

There have been extremely sharp fluctuations in the oil price since the 1970s; but to understand their effects on the economy, we must know the nature of the shock caused by oil price fluctuations . Is this a : Supply shock, related to fluctuations in companies' production costs? Demand shock, related to changes in inflation and household purchasing power? Kno wing the answer is important to define the economic policy response: using demand-side policies (fiscal policy) makes sense only if there is a demand shock . We defend the following idea : In the past, wages were price indexed; oil price fluctuations had little effect on real wages, and therefore generated supply shocks, borne entirely by companies; Nowadays, wages are weakly indexed to prices, so that fluctuations in the oil price affect real wages and have little effect on companies, and are therefore demand shocks.