I have looked a little bit into this (even though I haven't found much).

The following are the key bzr revisions:

    110785 -- OK

    110786..110811 -- Don't build on OS X (error during dump)

    110812..111504 -- Broken in another way. When pressing <down> <tab> over an over again, Emacs gets stuck. Neither <tab> nor <down> will do anything. However, typing a plain character makes Emacs escape this state and start being responsive again. This seems to be an OS X related problem, as the fix was applied to nsterm.m.

    111505 -- Broken as described in the original posts.

I hope this can shed some light on this, as this is a real problem that will affect lots of users. One thing we should try to figure out is if this is a problem specific to OS X, or if it is generic.

Sincerely,
    Anders Lindgren


On Mon, Jan 20, 2014 at 4:36 PM, Anders Lindgren <andlind@gmail.com> wrote:
I just sent out the previous letter before it was finished, so here comes the rest of it (sorry about that):

Steps to repeat:

    emacs -Q
    Evaluate the following:
    (save-excursion
     (insert "(")
     (dotimes (x 10) (insert "abc\n")))
    C-g       (Just to know where you are in C-h l)
    Now press TAB and down arrow over and over again, as fast as you can, like you're reindenting code.
    After a few lines, Emacs stops to indent. Looking at the end of C-h l, you will see something like:

C-g <tab> <down> <down>
<tab> <down> <tab> <down> <tab> <down> <tab> C-h l

    Here, a <tab> is missing, which explains the indentation problems.

Sincerely,
    Anders Lindgren



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