GNU bug report logs - #8340
23.2; recompile does not retain compilation-environment needed by vc-git-grep

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Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: Trevor Spiteri <tspiteri <at> ieee.org>
To: bug-gnu-emacs <at> gnu.org
Subject: 23.2; recompile does not retain compilation-environment needed by
	vc-git-grep
Date: Thu, 24 Mar 2011 18:45:12 +0000

Version 23.2.

In the function vc-git-grep inside vc-git.el, the compilation 
environment is set as

    (compilation-environment '("PAGER="))

because git grep needs that. If I use M-x recompile in the *grep* buffer 
after using M-x vc-git-grep, compilation-environment is not set, and a 
warning that the "terminal is not fully functional" is displayed, one 
page of results is shown, and git grep blocks waiting on standard input, 
since it is using more as a pager.

To fix this, I applied the following patch to compile.el that stores 
compile-environment in a similar way to default-directory. It works for 
me, but I do not really know elisp.

--- a/compile.el    2011-03-24 18:24:01.000000000 +0000
+++ b/compile.el    2011-03-24 18:27:44.000000000 +0000
@@ -511,6 +511,9 @@
 (defvar compilation-directory nil
   "Directory to restore to when doing `recompile'.")

+(defvar recompilation-environment nil
+  "Environment to restore when doing `recompile'.")
+
 (defvar compilation-directory-matcher
   '("\\(?:Entering\\|Leavin\\(g\\)\\) directory `\\(.+\\)'$" (2 . 1))
   "A list for tracking when directories are entered or left.
@@ -1106,7 +1109,8 @@
 If the optional argument `edit-command' is non-nil, the command can be 
edited."
   (interactive "P")
   (save-some-buffers (not compilation-ask-about-save) nil)
-  (let ((default-directory (or compilation-directory default-directory)))
+  (let ((default-directory (or compilation-directory default-directory))
+        (compilation-environment (or recompilation-environment 
compilation-environment)))
     (when edit-command
       (setcar compilation-arguments
               (compilation-read-command (car compilation-arguments))))
@@ -1236,6 +1240,7 @@
         ;; affected by the special handling of "cd ...;".
         ;; NB: must be fone after (funcall mode) as that resets local 
variables
         (set (make-local-variable 'compilation-directory) thisdir)
+        (set (make-local-variable 'recompilation-environment) 
compilation-environment)
     (if highlight-regexp
         (set (make-local-variable 'compilation-highlight-regexp)
          highlight-regexp))

Message #8 received at 8340 <at> debbugs.gnu.org (full text, mbox):

From: Juri Linkov <juri <at> jurta.org>
To: Trevor Spiteri <tspiteri <at> ieee.org>
Cc: 8340 <at> debbugs.gnu.org
Subject: Re: 23.2; recompile does not retain compilation-environment needed by
	vc-git-grep
Date: Mon, 05 Sep 2011 12:10:05 +0300

> In the function vc-git-grep inside vc-git.el, the compilation environment
> is set as
>
>     (compilation-environment '("PAGER="))
>
> because git grep needs that. If I use M-x recompile in the *grep* buffer
> after using M-x vc-git-grep, compilation-environment is not set, and
> a warning that the "terminal is not fully functional" is displayed, one
> page of results is shown, and git grep blocks waiting on standard input,
> since it is using more as a pager.
>
> To fix this, I applied the following patch to compile.el that stores
> compile-environment in a similar way to default-directory. It works for me,
> but I do not really know elisp.

Generally it would be better to reuse `compilation-environment' and set
it buffer-locally in the *compilation* buffer, but there is another problem.
Some users might want to set `compilation-environment' in .emacs like:

  (add-hook 'compilation-mode-hook
            (lambda ()
              (setq compilation-environment '("LANG=C"))))

See more in http://thread.gmane.org/gmane.emacs.devel/108353

But then let-binding (let ((compilation-environment '("PAGER="))))
in `vc-git-grep' is ineffective because `compilation-mode-hook'
overrides it.  So `compilation-environment' should be defcustom
to avoid this problem.

I don't know whether it's good for defcustom to be buffer-local.  But this
should fix both problems when `vc-git-grep' will add "PAGER=" to the
default or customized value of `compilation-environment' like
(let ((compilation-environment (cons "PAGER=" compilation-environment))))

Message #11 received at 8340 <at> debbugs.gnu.org (full text, mbox):

From: Juri Linkov <juri <at> jurta.org>
To: Trevor Spiteri <tspiteri <at> ieee.org>
Cc: 8340 <at> debbugs.gnu.org
Subject: Re: bug#8340: 23.2;
	recompile does not retain compilation-environment needed by
	vc-git-grep
Date: Tue, 06 Sep 2011 12:27:19 +0300

> Generally it would be better to reuse `compilation-environment' and set
> it buffer-locally in the *compilation* buffer, but there is another problem.
> Some users might want to set `compilation-environment' in .emacs like:
>
>   (add-hook 'compilation-mode-hook
>             (lambda ()
>               (setq compilation-environment '("LANG=C"))))
>
> See more in http://thread.gmane.org/gmane.emacs.devel/108353
>
> But then let-binding (let ((compilation-environment '("PAGER="))))
> in `vc-git-grep' is ineffective because `compilation-mode-hook'
> overrides it.  So `compilation-environment' should be defcustom
> to avoid this problem.

The following patch fixed all these problems:

=== modified file 'lisp/progmodes/compile.el'
--- lisp/progmodes/compile.el	2011-09-02 16:38:40 +0000
+++ lisp/progmodes/compile.el	2011-09-06 09:23:31 +0000
@@ -637,11 +637,15 @@ (defvar compilation-exit-message-functio
 and exit message; it returns a cons (MESSAGE . MODELINE) of the strings to
 write into the compilation buffer, and to put in its mode line.")
 
-(defvar compilation-environment nil
-  "*List of environment variables for compilation to inherit.
+(defcustom compilation-environment nil
+  "List of environment variables for compilation to inherit.
 Each element should be a string of the form ENVVARNAME=VALUE.
 This list is temporarily prepended to `process-environment' prior to
-starting the compilation process.")
+starting the compilation process."
+  :type '(repeat (string :tag "ENVVARNAME=VALUE"))
+  :options '(("LANG=C"))
+  :group 'compilation
+  :version "24.1")
 
 ;; History of compile commands.
 (defvar compile-history nil)
@@ -1482,6 +1491,7 @@ (defun compilation-start (command &optio
 	      "compilation"
 	    (replace-regexp-in-string "-mode\\'" "" (symbol-name mode))))
 	 (thisdir default-directory)
+	 (thisenv compilation-environment)
 	 outwin outbuf)
     (with-current-buffer
 	(setq outbuf
@@ -1530,6 +1541,7 @@ (defun compilation-start (command &optio
         ;; affected by the special handling of "cd ...;".
         ;; NB: must be fone after (funcall mode) as that resets local variables
         (set (make-local-variable 'compilation-directory) thisdir)
+	(set (make-local-variable 'compilation-environment) thisenv)
 	(if highlight-regexp
 	    (set (make-local-variable 'compilation-highlight-regexp)
 		 highlight-regexp))

=== modified file 'lisp/vc/vc-git.el'
--- lisp/vc/vc-git.el	2011-09-01 07:29:56 +0000
+++ lisp/vc/vc-git.el	2011-09-06 09:19:48 +0000
@@ -998,7 +998,7 @@ (defun vc-git-grep (regexp &optional fil
 	    (add-to-history 'grep-history command))))
       (when command
 	(let ((default-directory dir)
-	      (compilation-environment '("PAGER=")))
+	      (compilation-environment (cons "PAGER=" compilation-environment)))
 	  ;; Setting process-setup-function makes exit-message-function work
 	  ;; even when async processes aren't supported.
 	  (compilation-start command 'grep-mode))

Message #14 received at 8340 <at> debbugs.gnu.org (full text, mbox):

From: Stefan Monnier <monnier <at> IRO.UMontreal.CA>
To: Juri Linkov <juri <at> jurta.org>
Cc: 8340 <at> debbugs.gnu.org, Trevor Spiteri <tspiteri <at> ieee.org>
Subject: Re: bug#8340: 23.2;
	recompile does not retain compilation-environment needed by
	vc-git-grep
Date: Tue, 06 Sep 2011 14:39:58 -0400

> -(defvar compilation-environment nil
> -  "*List of environment variables for compilation to inherit.
> +(defcustom compilation-environment nil
> +  "List of environment variables for compilation to inherit.
>  Each element should be a string of the form ENVVARNAME=VALUE.
>  This list is temporarily prepended to `process-environment' prior to
> -starting the compilation process.")
> +starting the compilation process."
> +  :type '(repeat (string :tag "ENVVARNAME=VALUE"))
> +  :options '(("LANG=C"))
> +  :group 'compilation
> +  :version "24.1")

What is this supposed to fix?

>  ;; History of compile commands.
>  (defvar compile-history nil)
> @@ -1482,6 +1491,7 @@ (defun compilation-start (command &optio
>  	      "compilation"
>  	    (replace-regexp-in-string "-mode\\'" "" (symbol-name mode))))
>  	 (thisdir default-directory)
> +	 (thisenv compilation-environment)
>  	 outwin outbuf)
>      (with-current-buffer
>  	(setq outbuf
> @@ -1530,6 +1541,7 @@ (defun compilation-start (command &optio
>          ;; affected by the special handling of "cd ...;".
>          ;; NB: must be fone after (funcall mode) as that resets local variables
>          (set (make-local-variable 'compilation-directory) thisdir)
> +	(set (make-local-variable 'compilation-environment) thisenv)
>  	(if highlight-regexp
>  	    (set (make-local-variable 'compilation-highlight-regexp)
>  		 highlight-regexp))

> === modified file 'lisp/vc/vc-git.el'
> --- lisp/vc/vc-git.el	2011-09-01 07:29:56 +0000
> +++ lisp/vc/vc-git.el	2011-09-06 09:19:48 +0000
> @@ -998,7 +998,7 @@ (defun vc-git-grep (regexp &optional fil
>  	    (add-to-history 'grep-history command))))
>        (when command
>  	(let ((default-directory dir)
> -	      (compilation-environment '("PAGER=")))
> +	      (compilation-environment (cons "PAGER=" compilation-environment)))
>  	  ;; Setting process-setup-function makes exit-message-function work
>  	  ;; even when async processes aren't supported.
>  	  (compilation-start command 'grep-mode))

Mixing defcustom+bufferlocal+letbinding is really asking for trouble,
although I think in this case it might just fall within the limits of
what does work.
The vc-git.el patch looks perfectly good and so does the (set...thisenv).
But I'd prefer to refrain from making compilation-environment a defcustom
for now, until we find a really good use for it.


        Stefan

Message #17 received at 8340 <at> debbugs.gnu.org (full text, mbox):

From: Juri Linkov <juri <at> jurta.org>
To: Stefan Monnier <monnier <at> IRO.UMontreal.CA>
Cc: 8340 <at> debbugs.gnu.org, Trevor Spiteri <tspiteri <at> ieee.org>
Subject: Re: bug#8340: 23.2;
	recompile does not retain compilation-environment needed by
	vc-git-grep
Date: Wed, 07 Sep 2011 15:19:33 +0300

> Mixing defcustom+bufferlocal+letbinding is really asking for trouble,
> although I think in this case it might just fall within the limits of
> what does work.
>
> The vc-git.el patch looks perfectly good and so does the (set...thisenv).

Installed.

> But I'd prefer to refrain from making compilation-environment a defcustom
> for now, until we find a really good use for it.

There have been requests to make it a defcustom, and you even agreed to that ;-)
http://lists.gnu.org/archive/html/emacs-devel/2009-02/msg00118.html

It will allow the users to find and change it more easily in cases like this:
http://lists.gnu.org/archive/html/help-gnu-emacs/2011-02/msg00338.html

Message #20 received at 8340 <at> debbugs.gnu.org (full text, mbox):

From: Stefan Monnier <monnier <at> iro.umontreal.ca>
To: Juri Linkov <juri <at> jurta.org>
Cc: 8340 <at> debbugs.gnu.org, Trevor Spiteri <tspiteri <at> ieee.org>
Subject: Re: bug#8340: 23.2;
	recompile does not retain compilation-environment needed by
	vc-git-grep
Date: Wed, 07 Sep 2011 09:36:42 -0400

>> But I'd prefer to refrain from making compilation-environment a defcustom
>> for now, until we find a really good use for it.
> There have been requests to make it a defcustom, and you even agreed
> to that ;-)
> http://lists.gnu.org/archive/html/emacs-devel/2009-02/msg00118.html
> It will allow the users to find and change it more easily in cases like this:
> http://lists.gnu.org/archive/html/help-gnu-emacs/2011-02/msg00338.html

OK, sounds fine, go ahead,


        Stefan

Message #25 received at 8340-done <at> debbugs.gnu.org (full text, mbox):

From: Juri Linkov <juri <at> jurta.org>
To: Stefan Monnier <monnier <at> iro.umontreal.ca>
Cc: 8340-done <at> debbugs.gnu.org, Trevor Spiteri <tspiteri <at> ieee.org>
Subject: Re: bug#8340: 23.2;
	recompile does not retain compilation-environment needed by
	vc-git-grep
Date: Thu, 08 Sep 2011 15:12:41 +0300

>>> But I'd prefer to refrain from making compilation-environment a defcustom
>>> for now, until we find a really good use for it.
>> There have been requests to make it a defcustom, and you even agreed
>> to that ;-)
>> http://lists.gnu.org/archive/html/emacs-devel/2009-02/msg00118.html
>> It will allow the users to find and change it more easily in cases like this:
>> http://lists.gnu.org/archive/html/help-gnu-emacs/2011-02/msg00338.html
>
> OK, sounds fine, go ahead,

Done.

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