What can I expect after having smoked weed and failing my drug test? General or dishonorable discharge?

Back in the dark ages (1970s) you would have been processes out of the service as unsuitable to serve. I did several separation investigations as a Captain back then. Things changed a lot. My guess is NJP and drug rehab. Do good and you’ll make it to the end of your enlistment.

DDs come from a General Court Martial and are for the worst offenses. Rule that one out.

I'm no legal scholar but I've only ever seen a Dishonorable or Bad Conduct Discharge after conviction at Court Martial. Those do carry felony convictions into the civilian world. Typically, what I saw over my career was those who popped hot on a drug screen were given Other than Honorable or General Discharge as services usually don't waste the effort on Court Martial for drug use unless there are other violations of UCMJ along with it. General or OTH doesn't have felony status but you'll still staple that to every job application you submit for the rest of your life. Add to that, loss of education and VA benefits as those are tied to Honorable Discharge.

Best case assuming there are no previous disciplinary actions, you'll get Article 15 actions, be sent to a substance abuse program, and with luck retained in the service (at least until the end of your current enlistment). Whether your Commander recommends/approves reenlistment down the road could depend on to many factors to address here.

It's up to your command but typically drug use gets you a OTH. Out of curiosity, just how much freaking weed did you smoke? Typically the detection limits are set so that you could smoke a little weed on Saturday and piss clean on Tuesday. You either have to smoke a lot in a short time or a little over a long time or just be really unlucky to get popped for weed on a piss test. I know a guy who smoked weed on a regular basis for his entire career and never failed a drug test.

It isn't like they show on television shows where you can just "get" a dishonorable discharge. It has to be awarded by a General Court Martial as part of the sentence. Even then they have to go through so many channels to get it approved. Getting busted with weed isn't going to get you a DD With an otherwise clean record (?) they may only hit you with an Article 15. We don't know your service history.

Does the Army kick out E4's on first offense these days? I would have given you an Article 15, bust you a rank and refer you to ASAP. Whether you had a career after would depend on you performance in ASAP and at work.

DD or BCD only come with Courts-Martial. They are punitive. OTH is administrative, but requires the following:
a pattern of continued misconduct
an act of serious misconduct
abuse of authority
fraternization.
General is always under Honorable conditions. Those saying General OTH don't know what they are talking about.

As others have said, it'd likely just be a General OTH. However, depending on your unit and how you have been as a Soldier up to this point, you might just get knocked down in rank and sent to a substance abuse program. However, your career is going to take a major hit regardless.

My guess: No court martial so, therefore, no dishonorable discharge or bad conduct discharge. I really don't think that you need to worry about that. Other than that I'm sure that some Army personnel will chime in for what is the usual Army procedure for this violation.

I got out in 2001.
Then, 1st offense you'd get an Art-15, usually a company grade depending on how contrite you were. Expect a loss of rank, 30/30 and an involuntary contribution to the soldiers home.
In addition, you'll likely have to attend substance abuse classes.
What ever you do, you don't want to leave the Army with anything other than an honorable discharge.
That will affect VA benefits, and you really don't want that.