Getting "To" header fails on hundrets of messages

[matthiasbeyer]

Hi.

I don't know how to debug this, that's why I came here to ask for help.

I have a tag ml for mailinglist emails. It has 717 mails right now. Executing notmuch search tag:ml on the commandline prints them all fine.

But using the Rust interface, it fails to fetch the To header for more than half of them. I don't know why.
Can someone help me?

[OJFord]

Do those messages have a To header? I just noticed myself that .header("foo") (-> Result<Option<Cow<str>, Error>) returns error if the header is not set. Ok(None) only comes in to play if it is set to the empty string (which, surely, we want to be Ok(Some(""))?). About to open an issue specifically about this, but I noticed yours and thought it could potentially be the reason, if not the issue linked above.

Actually, disregard that, I realised in writing up the issue and some more testing/reading that it's actually libnotmuch (I think? I don't think it's an issue here..) not supporting its separate mail_root and db_path paths. If I symlink db_path subdirectories to those in mail_root, it works fine.