bug#48478: 28.0.50; yank-from-kill-ring and kill-ring-yank-pointer

[Eli Zaretskii <eliz@gnu.org>]

If one uses "C-y M-y M-y ... C-y", the last C-y will yank the
same kill-ring entry that the M-y before it.  But if one uses
"M-y M-y ... C-y", the last C-y will yank not the entry produced
by the last M-y, but the one after it.  Which means
yank-from-kill-ring leaves the kill-ring-yank-pointer at a different
entry than yank-pop does.

Bug or feature?  If the latter, what is the rationale for the
different operation?



In GNU Emacs 28.0.50 (build 1311, i686-pc-mingw32)
 of 2021-05-17 built on HOME-C4E4A596F7
Repository revision: e761e12498ff108c3b82e9d27843baec6670447c
Repository branch: master
Windowing system distributor 'Microsoft Corp.', version 5.1.2600
System Description: Microsoft Windows XP Service Pack 3 (v5.1.0.2600)

Configured using:
 'configure -C --prefix=/d/usr --with-wide-int --with-modules
 --enable-checking=yes,glyphs 'CFLAGS=-O0 -gdwarf-4 -g3''

Configured features:
ACL GIF GMP GNUTLS HARFBUZZ JPEG JSON LCMS2 LIBXML2 MODULES NOTIFY
W32NOTIFY PDUMPER PNG RSVG SOUND THREADS TIFF TOOLKIT_SCROLL_BARS XPM
ZLIB

Important settings:
  value of $LANG: ENU
  locale-coding-system: cp1255

Major mode: Lisp Interaction

Minor modes in effect:
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  eldoc-mode: t
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Load-path shadows:
None found.

Features:
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Memory information:
((conses 16 58121 11610)
 (symbols 48 7814 1)
 (strings 16 21681 2700)
 (string-bytes 1 636473)
 (vectors 16 13335)
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