>From 118c8a43510a7d3020a552ce0e87e5a1b9ccec54 Mon Sep 17 00:00:00 2001 From: Samuel Freilich Date: Wed, 23 Aug 2017 13:40:45 -0400 Subject: [PATCH] Do not split line before width of fill-prefix When auto-filling a paragraph, don't split a line before the width of the fill-prefix, creating a subsequent line that is as long or longer (Bug#20774). * lisp/simple.el (do-auto-fill): Only consider break-points that are later in the line than the width of the fill-prefix. This is a more general solution than the previous logic, which only skipped over the exact fill-prefix. The fill-prefix doesn't necessarily match the prefix of the first line of a paragraph in adaptive-fill-mode. --- lisp/simple.el | 27 ++++++++++++--------------- test/lisp/simple-tests.el | 11 +++++++++++ 2 files changed, 23 insertions(+), 15 deletions(-) diff --git a/lisp/simple.el b/lisp/simple.el index 13cfa3487d..27990bb661 100644 --- a/lisp/simple.el +++ b/lisp/simple.el @@ -7151,18 +7151,18 @@ do-auto-fill (setq fill-prefix prefix)))) (while (and (not give-up) (> (current-column) fc)) - ;; Determine where to split the line. - (let* (after-prefix - (fill-point - (save-excursion - (beginning-of-line) - (setq after-prefix (point)) - (and fill-prefix - (looking-at (regexp-quote fill-prefix)) - (setq after-prefix (match-end 0))) - (move-to-column (1+ fc)) - (fill-move-to-break-point after-prefix) - (point)))) + ;; Determine where to split the line. + (let ((fill-point + (save-excursion + (beginning-of-line) + ;; Don't split earlier in the line than the length of the + ;; fill prefix, since the resulting line would be longer. + (when fill-prefix + (move-to-column (string-width fill-prefix))) + (let ((after-prefix (point))) + (move-to-column (1+ fc)) + (fill-move-to-break-point after-prefix) + (point))))) ;; See whether the place we found is any good. (if (save-excursion @@ -7170,9 +7170,6 @@ do-auto-fill (or (bolp) ;; There is no use breaking at end of line. (save-excursion (skip-chars-forward " ") (eolp)) - ;; It is futile to split at the end of the prefix - ;; since we would just insert the prefix again. - (and after-prefix (<= (point) after-prefix)) ;; Don't split right after a comment starter ;; since we would just make another comment starter. (and comment-start-skip diff --git a/test/lisp/simple-tests.el b/test/lisp/simple-tests.el index ad7aee1db1..c7330e4034 100644 --- a/test/lisp/simple-tests.el +++ b/test/lisp/simple-tests.el @@ -497,5 +497,16 @@ simple-test-undo-with-switched-buffer (should (equal (line-number-at-pos 5) 3)) (should (equal (line-number-at-pos 7) 4))))) +(ert-deftest auto-fill-mode-no-break-before-length-of-fill-prefix () + (with-temp-buffer + (setq-local fill-prefix " ") + (set-fill-column 5) + ;; Shouldn't break after 'foo' (3 characters) when the next + ;; line is indented >= to that, that woudln't result in shorter + ;; lines. + (insert "foo bar") + (do-auto-fill) + (should (string-equal (buffer-string) "foo bar")))) + (provide 'simple-test) ;;; simple-test.el ends here -- 2.14.1.342.g6490525c54-goog