Stop joins at quote and signature boundaries
04Only lines at the same quote depth share a paragraph. Signature separators are a special boundary even though they end in SPACE.
A final flowed line lacks the normal fixed terminator. End of body still ends the paragraph; no extra line or following speaker is invented.
Source for this drawing: RFC 3676 · Read RFC section 4.5 ↗
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A soft break cannot erase a change of speaker.
- All lines of a generated paragraph MUST be unquoted or all quoted at the same depth. The line before a depth change MUST NOT be flowed.
- For malformed input, a receiver SHOULD apply quote-depth-wins: stop the paragraph before the depth change. Reformatting quoted text SHOULD de-quote, reflow and re-quote at the original depth.
- The exact signature separator -- SPACE is neither fixed nor flowed, including quoted/stuffed forms. Senders MUST NOT use it to end a paragraph or create it inside one. Receivers SHOULD terminate a malformed pending paragraph before it; end of body also ends a paragraph.
A Usenet-style signature is a written sign-off, not a cryptographic signature. Test the separator before quote processing and again after quote/stuffing removal. The empty line is fixed; an all-space line after removing stuffing is flowed if at least one SPACE remains. Error recovery does not grant senders permission to create the malformed cases shown.
Read the RFC section ↗