Revalidation webhook failure when unpublishing

[jmsv]

Happened with blog post, probably happens with events too

Can find webhook logs for this on Sanity dashboard under API tab

HTTP 500 with message "Error revalidating"

Unpublish 'works' in the sense that it'll no longer appear on the homepage or blog page, but the blog post page is still accessible directly via URL

Pretty sure this happens because:

1. Revalidate is called on the post page URL
2. getStaticProps is called which tries to load the blog post by slug
3. This fails because post isn't published

Currently have this code in getStaticProps:

const blogPost = await getBlogPostBySlug(
  context.params?.slug as string | undefined
);

if (!blogPost) return { notFound: true };

I'm guessing (haven't validated that this is correct) that getBlogPostBySlug throws when not found (which fails the revalidate) and !blogPost condition never hits to return the 404