uint256 amount = (rewardState * userRewards) / globalRewards;
File: PirexRewards.sol
368:     /**
369:         @notice Claim rewards
370:         @param  producerToken  ERC20    Producer token contract
371:         @param  user           address  User
372:     */
373:     function claim(ERC20 producerToken, address user) external {
374:         if (address(producerToken) == address(0)) revert ZeroAddress();
375:         if (user == address(0)) revert ZeroAddress();
376: 
377:         harvest();
378:         userAccrue(producerToken, user);
379: 
380:         ProducerToken storage p = producerTokens[producerToken];
381:         uint256 globalRewards = p.globalState.rewards;
382:         uint256 userRewards = p.userStates[user].rewards;
383: 
384:         // Claim should be skipped and not reverted on zero global/user reward
385:         if (globalRewards != 0 && userRewards != 0) {
386:             ERC20[] memory rewardTokens = p.rewardTokens;
387:             uint256 rLen = rewardTokens.length;
388: 
389:             // Update global and user reward states to reflect the claim
390:             p.globalState.rewards = globalRewards - userRewards;
391:             p.userStates[user].rewards = 0;
392: 
393:             emit Claim(producerToken, user);
394: 
395:             // Transfer the proportionate reward token amounts to the recipient
396:             for (uint256 i; i < rLen; ++i) {
397:                 ERC20 rewardToken = rewardTokens[i];
398:                 address rewardRecipient = p.rewardRecipients[user][rewardToken];
399:                 address recipient = rewardRecipient != address(0)
400:                     ? rewardRecipient
401:                     : user;
402:                 uint256 rewardState = p.rewardStates[rewardToken];
403:                 uint256 amount = (rewardState * userRewards) / globalRewards;
404: 
405:                 if (amount != 0) {
406:                     // Update reward state (i.e. amount) to reflect reward tokens transferred out
407:                     p.rewardStates[rewardToken] = rewardState - amount;
408: 
409:                     producer.claimUserReward(
410:                         address(rewardToken),
411:                         amount,
412:                         recipient
413:                     );
414:                 }
415:             }
416:         }
417:     }
amount = (rewardState * userRewards) / globalRewards;
amount = (rewardState * userRewards) / globalRewards;
60,000 * 6 / 600,000
360,000/600,000 = 0.6 = 0
function claim(ERC20 producerToken, address user) external {
..SNIP..
			uint256 amount = (rewardState * userRewards) / globalRewards;

			if (amount != 0) {
				// Update reward state (i.e. amount) to reflect reward tokens transferred out
				p.rewardStates[rewardToken] = rewardState - amount;

				producer.claimUserReward(
					address(rewardToken),
					amount,
					recipient
				);
-			}
+			} else {
+				revert ZeroRewardTokens();
+			}
..SNIP..
}
