Now I really have broken the build

Sorry, I'm not sure what you mean. When I added the new TableGen reference a couple of weeks ago, I don't recall adding it to any list of documents. It appeared as if every document in the docs/ directories was built.

(OFF TOPIC)

for me, your emails are not properly nested in the thread for some reason.
If this is the same for others you might want to check your local email setup.

Thanks,
Johanes

I came across the same error when adding a new doc, I had to add it to UserGuides.rst (https://reviews.llvm.org/D86979 for an example).

Let's see if this one is. I sent it by replying to the email with your post. I should also remember to leave the context below.

Looks good. Maybe my client was confused for some reason. Apologies for the noise.

Aha, you're right. It has to be listed in UserGuides.rst or referenced from a document listed in there. At least that appears to be the story. I will reference it from TableGen/index.rst, which I should do anyway.

Can you explain how I should then fix the build. Do I simply push a new patch?

Several of the emails in this thread were missing the In-Reply-To header. Some mail clients (e.g. Thunderbird) will only thread messages if they have a chain using that header or one of the closely related ones. This means you end up with split threads when someone doesn't reply properly. Others (e.g. Apple Mail) will use some heuristics to try to infer threads. This means you end up with weird interleaving of totally unrelated threads when the heuristic is incorrect.

In general, if you're replying to a mailing list post, please always use a reply button in your mail client and if your mail client then does not put the correct In-Reply-To header then please file a bug!

David