bug#36497: pop-to-buffer + quit-window negates with-current-buffer

bug#36497: pop-to-buffer + quit-window negates with-current-buffer

[Stefan Kangas]

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Steps to reproduce:

0. Run emacs -Q
1. Evaluate the following in *scratch* buffer:

(with-current-buffer (get-buffer-create "foo")
  (pop-to-buffer (get-buffer-create "bar"))
  (quit-window)
  (current-buffer))

Result:
#<buffer *scratch*>

Expected result:
#<buffer foo>

Please find attached also a suggested test case for this bug.

In GNU Emacs 27.0.50 (build 3, x86_64-apple-darwin15.6.0, NS
appkit-1404.47 Version 10.11.6 (Build 15G22010))
 of 2019-07-04 built on Stefans-MBP
Repository revision: 5b48dab412c61980bca63a67a5d548d07e56b404
Repository branch: master
Windowing system distributor 'Apple', version 10.3.1404
System Description:  Mac OS X 10.11.6

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diff --git a/test/lisp/subr-tests.el b/test/lisp/subr-tests.el
index 06db8f5c90..aa04d84dc3 100644
--- a/test/lisp/subr-tests.el
+++ b/test/lisp/subr-tests.el
@@ -400,5 +400,12 @@ subr-tests-add-hook-depth
   (should (equal subr-tests--hook '(f5 f10 f9 f6 f2 f1 f4 f3 f7 f8)))
   )
 
+(ert-deftest ert-tests-with-current-buffer/bug-XXXXX ()
+  (let ((buf (get-buffer-create "foo")))
+    (with-current-buffer buf
+      (pop-to-buffer (get-buffer-create "bar"))
+      (quit-window)
+      (should (equal (current-buffer) buf)))))
+
 (provide 'subr-tests)
 ;;; subr-tests.el ends here

bug#36497: pop-to-buffer + quit-window negates with-current-buffer

[martin rudalics]

 > Steps to reproduce:
 >
 > 0. Run emacs -Q
 > 1. Evaluate the following in *scratch* buffer:
 >
 > (with-current-buffer (get-buffer-create "foo")
 >    (pop-to-buffer (get-buffer-create "bar"))
 >    (quit-window)
 >    (current-buffer))
 >
 > Result:
 > #<buffer *scratch*>
 >
 > Expected result:
 > #<buffer foo>

Both 'pop-to-buffer' and 'quit-window' may call 'select-window' which
implicitly makes that window's buffer current.  In the case at hand,
'quit-window' deletes the window of *bar* since it didn't exist
before, selects the window selected before 'pop-to-buffer' was called
and makes that window's buffer current.  So the current behavior is
the expected one.

martin

bug#36497: pop-to-buffer + quit-window negates with-current-buffer

[Stefan Kangas]

martin rudalics <rudalics@gmx.at> writes:
> Both 'pop-to-buffer' and 'quit-window' may call 'select-window' which
> implicitly makes that window's buffer current.  In the case at hand,
> 'quit-window' deletes the window of *bar* since it didn't exist
> before, selects the window selected before 'pop-to-buffer' was called
> and makes that window's buffer current.  So the current behavior is
> the expected one.

Thanks for the detailed explanation -- that makes sense.

I'm closing the bug report.  Sorry about the noise.

Thanks,
Stefan Kangas