bug#27586: 25.1; sql-interactive-remove-continuation-prompt errors if sql-prompt-regexp is nil (default)

[Kevin Brubeck Unhammer]

The function sql-interactive-remove-continuation-prompt tries to
(string-match sql-prompt-regexp oline) and (string-match
sql-prompt-cont-regexp oline) but sql-prompt-regexp and
sql-prompt-cont-regexp default to nil. Reproducible from emacs -Q with
simply

(require 'sql)
(sql-interactive-remove-continuation-prompt "")


I got the bug when I tried using https://github.com/tumashu/sql-mssql
which uses sql.el, and presumably doesn't set these values. Maybe it
should, but it seems like sql.el would be more robust if it assumed they
could also have their default values :-)

Changing
                 (not (or (string-match sql-prompt-regexp oline)
                          (string-match sql-prompt-cont-regexp oline)))))

to

                 (not (or (and sql-prompt-regexp (string-match 
sql-prompt-regexp oline))
                          (and sql-prompt-cont-regexp (string-match 
sql-prompt-cont-regexp oline))))))

in sql-interactive-remove-continuation-prompt makes it work as expected
for me.




In GNU Emacs 25.1.1 (x86_64-pc-linux-gnu, GTK+ Version 3.22.11)
 of 2017-03-29, modified by Debian built on lgw01-37
Windowing system distributor 'The X.Org Foundation', version 11.0.11903000
System Description:     Ubuntu 17.04

Configured using:
 'configure --build x86_64-linux-gnu --prefix=/usr
 --sharedstatedir=/var/lib --libexecdir=/usr/lib
 --localstatedir=/var/lib --infodir=/usr/share/info
 --mandir=/usr/share/man --with-pop=yes
 
--enable-locallisppath=/etc/emacs25:/etc/emacs:/usr/local/share/emacs/25.1/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/25.1/site-lisp:/usr/share/emacs/site-lisp
 --with-sound=alsa --build x86_64-linux-gnu --prefix=/usr
 --sharedstatedir=/var/lib --libexecdir=/usr/lib
 --localstatedir=/var/lib --infodir=/usr/share/info
 --mandir=/usr/share/man --with-pop=yes
 
--enable-locallisppath=/etc/emacs25:/etc/emacs:/usr/local/share/emacs/25.1/site-lisp:/usr/local/share/emacs/site-lisp:/usr/share/emacs/25.1/site-lisp:/usr/share/emacs/site-lisp
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-fstack-protector-strong
 -Wformat -Werror=format-security -Wall' 'CPPFLAGS=-Wdate-time
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Configured features:
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ACL LIBSELINUX GNUTLS LIBXML2 FREETYPE M17N_FLT LIBOTF XFT ZLIB
TOOLKIT_SCROLL_BARS GTK3 X11

Important settings:
  value of $LC_MONETARY: nn_NO.UTF-8
  value of $LC_NUMERIC: nn_NO.UTF-8
  value of $LC_TIME: nn_NO.UTF-8
  value of $LANG: nn_NO.UTF-8
  locale-coding-system: utf-8-unix

Major mode: Lisp Interaction

Minor modes in effect:
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Recent messages:
For information about GNU Emacs and the GNU system, type C-h C-a.

Load-path shadows:
None found.

Features:
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Memory information:
((conses 16 87257 5017)
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