(fill-individual-paragraphs-prefix):

Avoid nil value of `two-lines-citation-part'

diff --git a/lisp/textmodes/fill.el b/lisp/textmodes/fill.el
index a4b515c0b659fd07ba7ecfbaedce25d58ab065ad..534e5e9d7548e0905b46f4fb4d4733a4b512b462 100644 (file)
--- a/lisp/textmodes/fill.el
+++ b/lisp/textmodes/fill.el
@@ -1087,6 +1087,7 @@ Also, if CITATION-REGEXP is non-nil,  don't fill header lines."
                    (fill-individual-paragraphs-citation two-lines-prefix
                                                         citation-regexp)
                  just-one-line-prefix))
+         (or two-lines-citation-part (setq two-lines-citation-part ""))
          (setq adjusted-two-lines-citation-part
                (substring two-lines-citation-part 0
                           (string-match "[ \t]*\\'"