cryptic error in automate()

[brandmaier]

If an RMarkdown has a broken header, where the final ---is missing, automate() gives a cryptic error:

Error in yaml_ind[[2]] : subscript out of bounds

[aaronpeikert]

I ought to find out how knitr is doing this... I have changed the rules for what constitutes a valid YAML head a dozen times.

[brandmaier]

I do my best to break it :-/