bug#26973: 26.0.50; sleep-for behavior changes with global-auto-revert-mode enabled

[Dmitry Gutov <dgutov@yandex.ru>]

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1. Copy stp-test.el and test.sh to the same directory.
2. Evaluate the .el file.
3. M-x global-auto-revert-mode.
4. M-x start-file-process-test.
5. See the message log. "sleeping done!" comes before "process done!".

Without step 3, "process done!" comes before "sleeping done!".

So it looks like, effectively, global-auto-revert-mode stops sleep-for
from calling process sentinels, at least.

I don't remember seeing anything like this in Emacs 25.

sit-for is not affected, BTW.

In GNU Emacs 26.0.50 (build 10, x86_64-pc-linux-gnu, GTK+ Version 3.20.9)
  of 2017-05-14 built on zappa
Repository revision: e6f64df9c2b443d3385c2c25c29ccd5283d37e3f
Windowing system distributor 'The X.Org Foundation', version 11.0.11804000
System Description:	Ubuntu 16.10

[-- Attachment #2: sfp-test.el --]
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(defun start-file-process-test ()
  (interactive)
  (let* ((buf (get-buffer-create "*test*"))
         (process (start-file-process "foo" buf
                                      (executable-find "sh")
                                      "./test.sh")))
    (set-process-sentinel
     process
     (lambda (proc status)
       (message "process done!")))
    (sleep-for 3)
    (message "sleeping done!")))

[-- Attachment #3: test.sh --]
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