We're saying the same thing. The player describes what they want to do, the DM then translates that to game mechanics using the rules.
That isn’t quite what I’m saying, though. Deciding how to resolve a player’s action declaration isn’t the same as simply matching it up with game mechanics. Besides, players usually have a pretty good idea of what mechanics they’re engaging when they act. If there’s a mismatch in expectations about what the rules are, then something like the following discussion may be necessary, but it isn’t ideal as an instance of play.
Player: "I want to run over to that monster, slam it in the face with my shield, and then attack it with my sword".
DM: "Great, you can use one of your attacks to shove it prone, and then make the second attack with advantage if you succeeded."
Player: "Why can't I attack it twice? I have the Shield Master feat."
DM: "You have to attack first before you get the bonus action to shove from that feat."
This is all an example of the sort of conversation that might happen when player and DM need to get on the same page about what mechanics are going to be involved in resolving the player’s declared action, but it hasn’t progressed beyond establishing exactly what the player’s action declaration is. I.e., there is no resolution forthcoming from the DM in your example, but rather mechanics are being used to tell the player what his/her action declaration can or can’t be. Now, this DM is free to interpret the text of Shield Master that way. That isn’t at issue. What’s at issue is that the DM is bringing the rules in to modify the player’s action declaration before adjudicating a resolution. I don’t see that as an appropriate use of the rules in play, which is why I don’t think it matters whether the character’s shove is an action or a bonus action, because either way the resolution is the same.
Again, we can agree to disagree here, but as Jeremy Crawford has explained at length, the standard phrasing of "if X, then Y" in the wording of bonus actions like Shield Master or Two-Weapon Fighting is the game's definition of timing restrictions for those bonus actions. He has also clarified that for this type of bonus action, the "X" part has to happen before the "Y" part. Perhaps they could've spent more time explaining this in greater detail in the PHB, but when the lead rules designer comes out and says "this is what we mean by these words in the PHB" then that's what the rules are, in my opinion.
And that’s a perfectly valid interpretation. What the official ruling doesn’t do, however, is overwrite the words in the books. It’s just an interpretation, not a rule.
Given the fact that the "if X, then Y" timing requirement is a trigger, and that X has to happen before Y, you have to actually take the Attack action before you can get a bonus action to shove someone from the Shield Master feat.
But that isn’t a given. That’s your interpretation.
The Sage Advice compendium is pretty clear about this. You can't skirt the rules by saying "well I declare that I'm going to take the Attack action on my turn" to get the bonus action first.
Right, well, I disagree with the compendium. That’s the point, isn’t it? It doesn’t do your argument any good to turn around and say, “But the compendium says...” I know what it says, and I disagree with it. What do you have to say about that? Also, I’ve never once said anything about declaring an action in order to “get” a bonus action, so it’s a waste of time telling me I can’t do that.
As I've said, I played the feat using the incorrect 2015 tweet for a long time. I think the difference here is that I'm willing to accept the new information from the lead rules designer of the game about how the feat is actually supposed to work, while you are not.
I’m actually very interested in the information Jeremy Crawford has put out about the game in general and about this feat specifically. I wouldn’t be participating in this thread if I wasn’t. That doesn’t mean I need to take everything he says as gospel truth.
Again, as JEC has explained in detail on many different platforms, the feat is not designed to just grant near-permanent advantage. If it was, then they would've just said "you have advantage on all weapon attacks while wearing a shield" or something similar.
But that isn’t what it does by anyone’s interpretation! You have to win a contest to gain advantage. It isn’t free!
When the lead rules designer says "this is what we intended" by a particular rule, yeah, I'm going to take that as a statement of intent as to how they expected the rules to work.
That’s great, but he hasn’t said that.
Jeremy Crawford said:
"RAI. Some of you are especially interested in knowing the intent behind a rule. That’s where RAI comes in: “rules as intended.” This approach is all about what the designers meant when they wrote something. In a perfect world, RAW and RAI align perfectly, but sometimes the words on the page don’t succeed in communicating the designers’ intent. Or perhaps the words succeed with one group of players but not with another.
When I write about the RAI interpretation of a rule, I’ll be pulling back the curtain and letting you know what the D&D team meant when we wrote a certain rule.”
This is a great quote, and I think we have a case here of where the RAW and RAI don’t align perfectly. Unfortunately, there has been no RAI interpretation issued by Crawford for this feat. I think the closest we have is his tweet from 2015. The interpretation he has issued more recently has been based solely on RAW, which he has decided to read in the most literalistic fashion possible. I can only speculate about his reasons for this, but I imagine it’s driven by a desire at some level of the company to have a consistent product.
You can obviously just ignore that and play some mental gymnastics to extract a meaning from the words that isn't designed to be there, I'm just pointing out that the Sage Advice compendium is quite clear that this is not the way the feat is supposed to work.
I don’t need the compendium to tell me how the feat is supposed to work. The meaning I derive is quite simple and requires no gymnastics.
For reference, I completely agree that the DM can ignore the strict RAW + RAI + Sage Advice on how Shield Master is supposed to work if that's what is best for their table and their players. I've been saying all along that if "following your bliss" as JEC advises means that you just play the feat as shove-slice-slice and everyone at your table has fun and combat encounters aren't trivialized, then that's great and you should absolutely continue to do that. There's no need to try to extract a different meaning from the wording of the feat or the other related rules to justify that position though, just ignore the rule and do what's best for your table.
Who are you agreeing with? It certainly isn’t me! There’s very little trying involved actually. There’s certainly no need for me to ignore anything. I don’t think you understand my position and that it’s easier for you to be rude than have a productive conversation. Have a nice day.