bug#19452: 24.4; sql-connect fails in first invocation: "Attempt to set a constant symbol: nil"

bug#19452: 24.4; sql-connect fails in first invocation: "Attempt to set a constant symbol: nil"

[JuanLeon Lahoz]

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First time in an emacs session I call interactively to sql-connect,
after I am prompted with the "Connection: " to use, emacs fails to
process the request with:

    eval: Attempt to set a constant symbol: nil

Subsequent invocations of the comman works fine

I can reproduce with emacs -Q, evalling this:

    (setq sql-connection-alist
           '(("foo"
              (sql-product  'mysql)
              (sql-database "foo")
              (sql-server   "localhost")
              (sql-user     "foo")
              (sql-password ""))))

And doing M-x sql-connect, then typing "foo" at the prompt.

I tried to use foo, instead of "foo" in the variable definition.  It is
the same.

If this is a bug, I would be happy to test a patch.

Thanks
juanleon


In GNU Emacs 24.4.1 (x86_64-unknown-linux-gnu, GTK+ Version 3.4.2)
 of 2014-12-26 on malaz
Windowing system distributor `The X.Org Foundation', version 11.0.11406000
System Description:    Ubuntu 12.04.5 LTS

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

Major mode: SQLi[MySQL]

Minor modes in effect:
  popwin-mode: t
  yas-global-mode: t
  yas-minor-mode: t
  global-auto-complete-mode: t
  shell-dirtrack-mode: t
  projectile-global-mode: t
  projectile-mode: t
  back-button-mode: t
  flx-ido-mode: t
  ido-everywhere: t
  global-yascroll-bar-mode: t
  yascroll-bar-mode: t
  winner-mode: t
  show-paren-mode: t
  auto-image-file-mode: t
  recentf-mode: t
  tooltip-mode: t
  electric-indent-mode: t
  mouse-wheel-mode: t
  file-name-shadow-mode: t
  global-font-lock-mode: t
  font-lock-mode: t
  auto-composition-mode: t
  auto-encryption-mode: t
  auto-compression-mode: t
  temp-buffer-resize-mode: t
  size-indication-mode: t
  column-number-mode: t
  line-number-mode: t

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bug#19452: 24.4; sql-connect fails in first invocation: "Attempt to set a constant symbol: nil"

[Nikolay Kudryavtsev]

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Ok, this bug has been bugging me long enough.

What happens is that there's a dynamic let block that looks like this:

(eval `(let ((,param-var ',rem-params))
                          (sql-product-interactive ',sql-product 
',new-name))))

Here's the code that sets param-var:

(setq param-var
           (sql-get-product-feature sql-product :sqli-login nil t))

It uses global variable sql-product. The default sql-product is ansi and 
running the above for it results in nil. Running "(let ((nil ..." leads 
to this error. In the same function there is a block that sets it to a 
proper value based on the current connection, but it is executed after 
param-var is already set. That's why the second time works.


I've attached a simple patch that just reorders code within sql-connect.

-- 
Best Regards,
Nikolay Kudryavtsev


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diff --git lisp/progmodes/sql.el lisp/progmodes/sql.el
index fd59f46..a6e7ec4 100644
--- lisp/progmodes/sql.el
+++ lisp/progmodes/sql.el
@@ -4040,6 +4040,12 @@ sql-connect
           (if connect-set
               ;; Set the desired parameters
               (let (param-var login-params set-params rem-params)
+                ;; Set the parameters and start the interactive session
+                (mapc
+                 #'(lambda (vv)
+                     (set-default (car vv) (eval (cadr vv))))
+                 (cdr connect-set))
+                (setq-default sql-connection connection)

                 ;; :sqli-login params variable
                 (setq param-var
@@ -4069,13 +4075,6 @@ sql-connect
                            (unless (member token set-params)
                              (if plist (cons token plist) token)))))

-                ;; Set the parameters and start the interactive session
-                (mapc
-                 #'(lambda (vv)
-                     (set-default (car vv) (eval (cadr vv))))
-                 (cdr connect-set))
-                (setq-default sql-connection connection)
-
                 ;; Start the SQLi session with revised list of login parameters
                 (eval `(let ((,param-var ',rem-params))
                          (sql-product-interactive ',sql-product ',new-name))))

bug#19452: 24.4; sql-connect fails in first invocation: "Attempt to set a constant symbol: nil"

[Nicolas Petton]

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Nikolay Kudryavtsev <nikolay.kudryavtsev@gmail.com> writes:

Hi Nikolay,


> +                (mapc
> +                 #'(lambda (vv)
> +                     (set-default (car vv) (eval (cadr vv))))

You don't need to sharp-quote lambdas.

Cheers,
Nico

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bug#19452: 24.4; sql-connect fails in first invocation: "Attempt to set a constant symbol: nil"

[Nikolay Kudryavtsev]

Yeah, thanks. I just didn't bother to change what was there originally. 
There's a lot more of them there too.

Looking at vc history, sql.el got infested by those sharp-quoted lambdas 
relatively recently, in 2013, at e18e61cf276880f658ab8cdf1f242a675b58cd71.

And I honestly can't blame the author for that. Even the current Elisp 
reference is a bit unclear on the use of sharp-quotes.

-- 
Best Regards,
Nikolay Kudryavtsev

bug#19452: 24.4; sql-connect fails in first invocation: "Attempt to set a constant symbol: nil"

[Nicolas Petton]

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Nikolay Kudryavtsev <nikolay.kudryavtsev@gmail.com> writes:

> Yeah, thanks. I just didn't bother to change what was there originally. 
> There's a lot more of them there too.

I fixed them in master (you'll need to update your patch).

Cheers,
Nico

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bug#19452: 24.4; sql-connect fails in first invocation: "Attempt to set a constant symbol: nil"

[Eli Zaretskii]

> From: Nicolas Petton <nicolas@petton.fr>
> Date: Tue, 26 Jul 2016 17:11:41 +0200
> 
> > Yeah, thanks. I just didn't bother to change what was there originally. 
> > There's a lot more of them there too.
> 
> I fixed them in master (you'll need to update your patch).

Thanks.  When you compiled sql.el, did you see the warning below?

  In sql-end-of-statement:
  progmodes/sql.el:2781:31:Warning: looking-back called with 1 argument, but
      requires 2-3

bug#19452: 24.4; sql-connect fails in first invocation: "Attempt to set a constant symbol: nil"

[Nicolas Petton]

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Eli Zaretskii <eliz@gnu.org> writes:

> Thanks.  When you compiled sql.el, did you see the warning below?
>
>   In sql-end-of-statement:
>   progmodes/sql.el:2781:31:Warning: looking-back called with 1 argument, but
>       requires 2-3

Yes, but I haven't changed anything related to this, or?

Cheers,
Nico

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bug#19452: 24.4; sql-connect fails in first invocation: "Attempt to set a constant symbol: nil"

[Nikolay Kudryavtsev]

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Here's the same patch made from the current master.

-- 
Best Regards,
Nikolay Kudryavtsev


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diff --git lisp/progmodes/sql.el lisp/progmodes/sql.el
index a11d456..9a7b746 100644
*** lisp/progmodes/sql.el
--- lisp/progmodes/sql.el
***************
*** 4040,4045 ****
--- 4040,4051 ----
            (if connect-set
                ;; Set the desired parameters
                (let (param-var login-params set-params rem-params)
+                 ;; Set the parameters and start the interactive session
+                 (mapc
+                  (lambda (vv)
+                    (set-default (car vv) (eval (cadr vv))))
+                  (cdr connect-set))
+                 (setq-default sql-connection connection)

                  ;; :sqli-login params variable
                  (setq param-var
***************
*** 4069,4081 ****
                             (unless (member token set-params)
                               (if plist (cons token plist) token)))))

-                 ;; Set the parameters and start the interactive session
-                 (mapc
-                  (lambda (vv)
-                      (set-default (car vv) (eval (cadr vv))))
-                  (cdr connect-set))
-                 (setq-default sql-connection connection)
-
                  ;; Start the SQLi session with revised list of login parameters
                  (eval `(let ((,param-var ',rem-params))
                           (sql-product-interactive ',sql-product ',new-name))))
--- 4075,4080 ----

bug#19452: status?

[root]

Hello

Just wondering why it's still not fixed.
Incorrect patch?

bug#19452: status?

[Eli Zaretskii]

> Date: Tue, 29 Nov 2016 22:01:42 +0100
> From: root@opow.pw
> 
> Just wondering why it's still not fixed.
> Incorrect patch?

Thanks for the reminder, I pushed the patch to the master branch.

bug#19452: status?

[root]

On Fri, Dec 02, 2016 at 11:55:01AM +0200, Eli Zaretskii wrote:
> > Date: Tue, 29 Nov 2016 22:01:42 +0100
> > From: root@opow.pw
> > 
> > Just wondering why it's still not fixed.
> > Incorrect patch?
> 
> Thanks for the reminder, I pushed the patch to the master branch.

Thanks!