What is the format of HTTP 1.1 header values?

Question

I read the rfc7230 section 3.2. After removing obsolete rules, the spec about header field is:

header-field   = field-name ":" OWS field-value OWS
field-name     = token
field-value    = *field-content
field-content  = field-vchar [ 1*( SP / HTAB ) field-vchar ]
field-vchar    = VCHAR
VCHAR          = %x21-7E; visible (printing) characters

I am confused by the definition of field-content. It seems that it matches 1 or 2 VCHARs, with any amount of space in between, but it will not match another space after a field-content match.

For example, for name:a<sp>b<sp>c, field-name will match name, but field-content will match a<sp>b and then the next <sp> cannot be matched by another field-content, thus this header is invalid.

However, name:a<sp>bc<sp>d is valid because there are two matches for field-content, a<sp>b and c<sp>d.

I think this is inconsistent. Is this intended or do I misunderstood something?

Answer 1

I know this is an old question, but :

The updated RFC 9110 Section 5.5 still holds this ambiguity. Therefore, i would suggest sticking to the explaination described here.