build before replacing?

[Fil]

We should build in build-current/, then on success “atomically” rename build/ to build-old/ and build-current to build, and finally rimraf build-old/. This would help to compare a broken build to the previous run. I would also ensure that a build is served locally without interruption, for workflows where it makes sense to do so (like sharing with ngrok or some such).

[mbostock]

Do you mean just in our repo, or do you mean observable build in general? The former should be readily doable, but the latter would be a fairly significant API change since we don’t do clean builds — people could already rely on the fact that we only add files to the giving dist folder and preserve what’s already there.

[Fil]

I meant for observable build in general, but I was confused as I was experiencing this situation in our repo while testing builds repeatedly. However, it's not needed in our repo, so let's do nothing. Thanks for the feedback!