❓ I’m running into an issue where pulumi is just hanging on trying to create AWS resources. There seems to be no indication of what it’s doing, it’s just… stopped, for at least a half an hour so far.

There are debug and verbosity options for the Pulumi CLI. As a possible shortcut: when Pulumi shows that's it's trying to do something in AWS, but that something never happens, I've found that it's (almost?) always expired temporary credentials. Refresh your MFA, SSO or whatever's in use, and try again.

So I had a hunch, and it seems like it was trying to create an S3 bucket that already existed in a different AWS account. I’m at a loss about why this hung instead of just immediately throwing an error.

Yes that doesn't sound like it should happen. If you wanted to create a trivial example and create an issue at https://github.com/pulumi/pulumi-aws/issues, that'd be good.

In my experience hangs are almost always from dependency blocks that are opaque to Pulumi e.g. trying to delete a subnet that is in use by an EC2 network interface, that sort of thing The solution is usually something like manually disassociate the resources by deleting one of them in the console