bug#31446: 26.1; sql-interactive-mode buffer naming is broken

[Phil Sainty]

Depending on whether/how many C-u prefix arguments I supply to
sql-postgres, the resulting buffer name is bad.

M-x sql-postgres: "*SQL: *"
C-u M-x sql-postgres: "*SQL: ^D*"
C-u C-u M-x sql-postgres: "*SQL: ^P*"

I've converted them for the bug report, but the ^D and ^P are actual
control characters, which I observe are characters 4 and 16
respectively, and therefore are a match for the numeric value of the
supplied prefix argument.  This is surely not what was intended.

In 25.3 the buffer name would be "*SQL*" with no prefix argument, and if
if a prefix argument was given I would be prompted for the buffer name,
with "*SQL: <user>@<database>*" as the default suggestion.


-Phil





In GNU Emacs 26.1 (build 1, x86_64-pc-linux-gnu, X toolkit, Xaw scroll 
bars)
 of 2018-04-11 built on mts-devtools
Windowing system distributor 'The X.Org Foundation', version 
11.0.11501000
System Description:     Ubuntu 14.04.5 LTS

Recent messages:
funcall-interactively: End of buffer [3 times]
Login...done
funcall-interactively: End of buffer
Entering debugger...
Continuing.
custom-initialize-reset: Symbol’s value as variable is void: buffer-name
"*SQL: *"
kill-region: Buffer is read-only: #<buffer *Messages*>
Scanning for dabbrevs...done
user-error: No dynamic expansion for ‘sql-int’ found

Configured using:
 'configure --prefix=/usr/local/src/emacs/26.1/usr/local
 --with-x-toolkit=lucid --without-sound'

Configured features:
XPM JPEG TIFF GIF PNG RSVG IMAGEMAGICK DBUS GSETTINGS NOTIFY GNUTLS
LIBXML2 FREETYPE XFT ZLIB TOOLKIT_SCROLL_BARS LUCID X11 THREADS LCMS2

Important settings:
  value of $LANG: en_NZ.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Messages

Minor modes in effect:
  tooltip-mode: t
  global-eldoc-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  tool-bar-mode: t
  menu-bar-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  blink-cursor-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  buffer-read-only: t
  line-number-mode: t
  transient-mark-mode: t

Load-path shadows:
None found.

Features:
(shadow sort mail-extr dabbrev emacsbug message rmc puny seq dired
dired-loaddefs format-spec rfc822 mml mml-sec password-cache epa derived
epg epg-config gnus-util rmail rmail-loaddefs mm-decode mm-bodies
mm-encode mail-parse rfc2231 mailabbrev gmm-utils mailheader sendmail
rfc2047 rfc2045 ietf-drums mm-util mail-prsvr mail-utils help-mode
cl-print byte-opt gv bytecomp byte-compile cconv debug sql easymenu view
thingatpt comint ansi-color ring cl-loaddefs cl-lib elec-pair time-date
mule-util tooltip eldoc electric uniquify ediff-hook vc-hooks
lisp-float-type mwheel term/x-win x-win term/common-win x-dnd tool-bar
dnd fontset image regexp-opt fringe tabulated-list replace newcomment
text-mode elisp-mode lisp-mode prog-mode register page menu-bar
rfn-eshadow isearch timer select scroll-bar mouse jit-lock font-lock
syntax facemenu font-core term/tty-colors frame cl-generic cham georgian
utf-8-lang misc-lang vietnamese tibetan thai tai-viet lao korean
japanese eucjp-ms cp51932 hebrew greek romanian slovak czech european
ethiopic indian cyrillic chinese composite charscript charprop
case-table epa-hook jka-cmpr-hook help simple abbrev obarray minibuffer
cl-preloaded nadvice loaddefs button faces cus-face macroexp files
text-properties overlay sha1 md5 base64 format env code-pages mule
custom widget hashtable-print-readable backquote dbusbind inotify lcms2
dynamic-setting system-font-setting font-render-setting x-toolkit x
multi-tty make-network-process emacs)

Memory information:
((conses 16 108297 11486)
 (symbols 48 21234 1)
 (miscs 40 119 276)
 (strings 32 31999 1264)
 (string-bytes 1 893910)
 (vectors 16 15325)
 (vector-slots 8 506954 12212)
 (floats 8 63 171)
 (intervals 56 329 0)
 (buffers 992 16)
 (heap 1024 45845 3308))