Subject: bug#38407: 27.0.50; infinite loop with display of large file without newlines

From: Phil Sainty <[email-masked]>
Date: Sun, 1 Dec 2019 23:37:46 +1300

On 1/12/19 8:23 PM, Pieter van Oostrum wrote:
> Here it is, compressed. I am loading the uncompressed file,
> of course.

Without bidi-inhibit-bpa, visual-line-mode is certainly brutal
with this file (I've been waiting several minutes for Emacs 27
to respond to `end-of-buffer').

However, for me, bidi-inhibit-bpa comprehensively deals to that.

Is it possible that you didn't recompile or reinstall Emacs in
the way you thought you had, after pulling Eli's changes?

Can you confirm that C-h v bidi-inhibit-bpa actually shows you
documentation about the variable?  If it doesn't, then setting
it will have no effect whatsoever.

-Phil

p.s. By default it should be telling you this:

bidi-inhibit-bpa is a variable defined in ‘C source code’.
Its value is nil

  Calls these functions when changed: (#<subr set-buffer-redisplay>)

Documentation:
Non-nil means inhibit the Bidirectional Parentheses Algorithm.
Disabling the BPA makes redisplay faster, but might produce incorrect
display reordering of bidirectional text with embedded parentheses and
other bracket characters whose ’paired-bracket’ Unicode property is
non-nil, see ‘get-char-code-property’.