Re: Strange behavior with 25.2 on macOS

["Charles A. Roelli" <charles@aurox.ch>]

Can you reproduce this behavior from emacs -q (i.e., without any
personal configuration)?

I tried the following to see if I could reproduce it:

src/emacs -q
M-x shell RET
yes RET ; some command that spews a lot of output
C-x 5 2 ; create a new frame
C-x b *scratch* RET

Followed by these steps:

> * Hitting ESC-x or ESC-:
> * `C-x 5 o` to switch from the window displaying the code buffer to the
> window displaying the shell buffer.

But the issue did not occur (the amount of lines in the *shell* buffer
keeps on increasing without pause).



On 03/08/2017 18:49, Barry Warsaw wrote:
> I have two Macs, both of which run macOS 10.12.6, and both of which have
> Emacs 25.2 installed from source via homebrew.  Both are up-to-date in
> brew and in installed packages.  On one machine, Emacs is working great,
> but on the other, I'm seeing some very strange behavior with subprocess
> output hanging.  I'm wondering if anybody has seen similar issues, or
> has any suggestions for debugging.
>
> Here's the most visible symptom:
>
> In a shell buffer, I run the `tox` command to run the test suite for GNU
> Mailman 3, which is a Python project.  This spews a lot of output to
> stdout.  If I have that running in one window and go to another window
> with some code in it, and hit C-g in that window, the stdout spew from
> tox just stops.  It'll sit there forever until I hit any other key than
> C-g.  As soon as I do, all the buffered output gets printed and tox
> continues its progress.  It's pretty consistent behavior, and isn't
> really related to tox (it'll happen with anything that streams out lots
> of text in a shell).
>
> Other things that stop output include:
>
> * Going to the beginning of the code buffer and hitting C-p.
> * Hitting ESC-x or ESC-: - in both cases the prompt appears in the
> minibuffer, but shell output stops.
> * `C-x 5 o` to switch from the window displaying the code buffer to the
> window displaying the shell buffer.
> * Going into the shell buffer and using either the `pushd` or `popd`
> bash commands.  I see the minibuffer echo the dir stack, but the shell
> prompt doesn't come back until I hit another key.  However, if the dir
> stack is empty and I popd, it comes back immediately.  cd to another
> directory can also hang the shell buffer.
>
> I don't think it's just the shell though because I can also see a hang
> when invoking git commit through magit.  I see 'Running git commit --'
> in the minibuffer, but it's not until I hit another key or something
> that the commit buffer actually comes up.  I generally `git commit -a
> -v` but I don't know if that's relevant.
>
> Other things that restart output include:
>
> * Going to Activity Monitor, selecting the Emacs process and hitting
> Sample to collect process details.  When the shell buffer is stopped, it
> doesn't seem particularly hungry with CPU, disk, memory, or any other
> system resource.
>
> The two machines are setup nearly identically.  One difference between
> them is that on the problematic machine I have the gnutls brew package
> installed (for gnupg), but I uninstalled that and reinstalled Emacs and
> verified that it makes no difference.  So yes, reinstalling Emacs
> doesn't solve the problem.  I haven't noticed any other weirdness with
> the machine exhibiting the Emacs problems.  I haven't completely
> verified that they both have the same packages installed, although what
> is installed are all up-to-date.
>
> Any suggestions will be greatly appreciated!  The problem is so
> frustrating. ;)
>
> Cheers,
> -Barry
>
>
>