Re: buff-menu.el changes

[Miles Bader <miles@lsi.nec.co.jp>]

Daniel Pfeiffer <occitan@esperanto.org> writes:
> Being able to move over intangible text charwise but not linewise sounds
> counterintuitive and would seem a 21.3 bug.

Almost certainly; the `line-move' function is chock full of special
code to deal with intangible characters, which in my experience breaks
often, and never _really_ works correctly.  I don't really understand
the it that well, but I think the problem often involves hidden
newline characters.

If anyone's interested, here's a simple test-case that illustrates the
problem:

   (with-current-buffer (get-buffer-create "*test*")
     (insert "1: hello\n")
     (insert (propertize "2: cruel\n" 'invisible t 'intangible t))
     (insert "3: world\n")
     (insert "4:\n"))

After evaluating that, go to the *test* buffer, and move around using
C-n & C-p.  I can see the following bugs:

  (1) If the cursor is in the first column, you can't move from line
      "3:" to line "4:" using C-n (but C-p works all the way from the
      end of the buffer to the beginning).

  (2) If the cursor is in a different column, C-n seems to work
      correctly on all lines, but C-p won't move from line "3:" to
      line "1:" (it seems to work on all other line though).

-Miles
-- 
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