bug#26049: 25.2; Extra lines not added to comment

bug#26049: 25.2; Extra lines not added to comment

[Antonin Houska]

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Even though I have the following customizations in place

 '(comment-multi-line t)
 '(comment-style (quote extra-line))

comment-region command produces this

/* some comment */

rather than this

/*
 * some comment
 */

Attached is a patch that I use to fix the issue on my workstation. Besides
fixing the (supposed) off-by-one error, the patch also removes trailing
whitespace from the initial line of the comment ("/* "). (My knowledge of
Elisp is not too advanced so I wonder if there's simpler way to trim
whitespace from a string.)




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-- 
Antonin Houska
Cybertec Schönig & Schönig GmbH
Gröhrmühlgasse 26
A-2700 Wiener Neustadt
Web: http://www.postgresql-support.de, http://www.cybertec.at


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[-- Attachment #2: comment_extra_line.diff --]
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diff --git a/lisp/newcomment.el b/lisp/newcomment.el
new file mode 100644
index 1af8929..75dbb07
*** a/lisp/newcomment.el
--- b/lisp/newcomment.el
*************** the region rather than at left margin."
*** 1139,1144 ****
--- 1139,1149 ----
  
  	  ;; make the leading and trailing lines if requested
  	  (when lines
+ 	    ;; Trim trailing whitespace from cs if there's some.
+ 	    (let ((wp-pos (string-match "\\s-+$" cs)))
+ 	      (if wp-pos
+ 		  (setq cs (substring cs 0 wp-pos))))
+ 
  	    (let ((csce
  		   (comment-make-extra-lines
  		    cs ce ccs cce min-indent max-indent block)))
*************** changed with `comment-style'."
*** 1209,1215 ****
  	   (progn (goto-char end) (end-of-line) (skip-syntax-backward " ")
  		  (<= (point) end))
  	   (or block (not (string= "" comment-end)))
! 	   (or block (progn (goto-char beg) (search-forward "\n" end t)))))
  
      ;; don't add end-markers just because the user asked for `block'
      (unless (or lines (string= "" comment-end)) (setq block nil))
--- 1214,1222 ----
  	   (progn (goto-char end) (end-of-line) (skip-syntax-backward " ")
  		  (<= (point) end))
  	   (or block (not (string= "" comment-end)))
! 	   (or block (progn (goto-char beg) (search-forward
!                                              "\n"
!                                              (min (1+ end) (point-max)) t)))))
  
      ;; don't add end-markers just because the user asked for `block'
      (unless (or lines (string= "" comment-end)) (setq block nil))

bug#26049: 25.2; Extra lines not added to comment

[npostavs]

Antonin Houska <ah@cybertec.at> writes:

> Even though I have the following customizations in place
>
>  '(comment-multi-line t)
>  '(comment-style (quote extra-line))
>
> comment-region command produces this
>
> /* some comment */
>
> rather than this
>
> /*
>  * some comment
>  */
>
> Attached is a patch that I use to fix the issue on my workstation. Besides
> fixing the (supposed) off-by-one error, the patch also removes trailing
> whitespace from the initial line of the comment ("/* "). (My knowledge of
> Elisp is not too advanced so I wonder if there's simpler way to trim
> whitespace from a string.)
>

You can use use `string-trim-right' from subr-x.

>   	   (progn (goto-char end) (end-of-line) (skip-syntax-backward " ")
>   		  (<= (point) end))
>   	   (or block (not (string= "" comment-end)))
> ! 	   (or block (progn (goto-char beg) (search-forward
> !                                              "\n"
> !                                              (min (1+ end) (point-max)) t)))))

Maybe (re-search-forward "$" end t) is better?  It's a bit unclear to me
what exactly all those tests are looking for.  That code could use some
comments...

bug#26049: 25.2; Extra lines not added to comment

[Antonin Houska]

[-- Attachment #1: Type: text/plain, Size: 1836 bytes --]

npostavs@users.sourceforge.net wrote:

> Antonin Houska <ah@cybertec.at> writes:

> > Even though I have the following customizations in place
> >
> >  '(comment-multi-line t)
> >  '(comment-style (quote extra-line))
> >
> > comment-region command produces this
> >
> > /* some comment */
> >
> > rather than this
> >
> > /*
> >  * some comment
> >  */
> >
> > Attached is a patch that I use to fix the issue on my workstation. Besides
> > fixing the (supposed) off-by-one error, the patch also removes trailing
> > whitespace from the initial line of the comment ("/* "). (My knowledge of
> > Elisp is not too advanced so I wonder if there's simpler way to trim
> > whitespace from a string.)
> >

> You can use use `string-trim-right' from subr-x.

Thanks.

> >   	   (progn (goto-char end) (end-of-line) (skip-syntax-backward " ")
> >   		  (<= (point) end))
> >   	   (or block (not (string= "" comment-end)))
> > ! 	   (or block (progn (goto-char beg) (search-forward
> > !                                              "\n"
> > !                                              (min (1+ end) (point-max)) t)))))

> Maybe (re-search-forward "$" end t) is better?  It's a bit unclear to me
> what exactly all those tests are looking for.  That code could use some
> comments...

I've just verified your approach - it does work too.

Yes, comments would be useful. For the test we're fixing now, the reason seems
to be to ensure that the last line of the comment can be broken w/o affecting
the following (non-comment) text. Perhaps someone else might come up with
better wording.

New version of the patch is attached.

-- 
Antonin Houska
Cybertec Schönig & Schönig GmbH
Gröhrmühlgasse 26
A-2700 Wiener Neustadt
Web: http://www.postgresql-support.de, http://www.cybertec.at


[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #2: newcomment_v2.diff --]
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diff --git a/lisp/newcomment.el b/lisp/newcomment.el
new file mode 100644
index 1af8929..f2d9735
*** a/lisp/newcomment.el
--- b/lisp/newcomment.el
***************
*** 69,74 ****
--- 69,77 ----
  
  ;;; Code:
  
+ (eval-when-compile
+   (require 'subr-x))
+ 
  ;;;###autoload
  (defalias 'indent-for-comment 'comment-indent)
  ;;;###autoload
*************** the region rather than at left margin."
*** 1139,1144 ****
--- 1142,1150 ----
  
  	  ;; make the leading and trailing lines if requested
  	  (when lines
+ 	    ;; Trim trailing whitespace from cs if there's some.
+             (setq cs (string-trim cs))
+ 
  	    (let ((csce
  		   (comment-make-extra-lines
  		    cs ce ccs cce min-indent max-indent block)))
*************** changed with `comment-style'."
*** 1209,1215 ****
  	   (progn (goto-char end) (end-of-line) (skip-syntax-backward " ")
  		  (<= (point) end))
  	   (or block (not (string= "" comment-end)))
! 	   (or block (progn (goto-char beg) (search-forward "\n" end t)))))
  
      ;; don't add end-markers just because the user asked for `block'
      (unless (or lines (string= "" comment-end)) (setq block nil))
--- 1215,1221 ----
  	   (progn (goto-char end) (end-of-line) (skip-syntax-backward " ")
  		  (<= (point) end))
  	   (or block (not (string= "" comment-end)))
! 	   (or block (progn (goto-char beg) (re-search-forward "$" end t)))))
  
      ;; don't add end-markers just because the user asked for `block'
      (unless (or lines (string= "" comment-end)) (setq block nil))

bug#26049: 25.2; Extra lines not added to comment

[npostavs]

Antonin Houska <ah@cybertec.at> writes:
>
>> >   	   (progn (goto-char end) (end-of-line) (skip-syntax-backward " ")
>> >   		  (<= (point) end))
>> >   	   (or block (not (string= "" comment-end)))
>> > ! 	   (or block (progn (goto-char beg) (search-forward
>> > !                                              "\n"
>> > !                                              (min (1+ end) (point-max)) t)))))
>
>> Maybe (re-search-forward "$" end t) is better?  It's a bit unclear to me
>> what exactly all those tests are looking for.  That code could use some
>> comments...
>
> I've just verified your approach - it does work too.

"$" also matches at the end of buffer even if it doesn't end in newline
(which is a very marginal corner case, I just happened to notice it
because I didn't hit RET in my test buffer).

> + 	    ;; Trim trailing whitespace from cs if there's some.
> +             (setq cs (string-trim cs))

This would trim leading whitespace too, do we want that?

bug#26049: 25.2; Extra lines not added to comment

[Antonin Houska]

npostavs@users.sourceforge.net wrote:

> Antonin Houska <ah@cybertec.at> writes:
> >
> >> >   	   (progn (goto-char end) (end-of-line) (skip-syntax-backward " ")
> >> >   		  (<= (point) end))
> >> >   	   (or block (not (string= "" comment-end)))
> >> > ! 	   (or block (progn (goto-char beg) (search-forward
> >> > !                                              "\n"
> >> > !                                              (min (1+ end) (point-max)) t)))))
> >
> >> Maybe (re-search-forward "$" end t) is better?  It's a bit unclear to me
> >> what exactly all those tests are looking for.  That code could use some
> >> comments...
> >
> > I've just verified your approach - it does work too.

> "$" also matches at the end of buffer even if it doesn't end in newline
> (which is a very marginal corner case, I just happened to notice it
> because I didn't hit RET in my test buffer).

IMO this is ok. If the 'extra-line value of `comment-style' tells that the
comment should look like this

/*
 * some comment
 */

it'd be kind of inconsistend if just a missing RET at the end of buffer
resulted in this

/* some comment */

which effectively means discrepancy from the customization setting.

(The initial version of my patch ignored the `extra-line' setting in this
special case, but it was a thinko rather than intention.)

> 
> > + 	    ;; Trim trailing whitespace from cs if there's some.
> > +             (setq cs (string-trim cs))
> 
> This would trim leading whitespace too, do we want that?

I haven't noticed any related issue but yes, string-trim-right is more
precise. If the (supposedly accidental) leading space should be removed from
the value of `comment-start', it should probably happen elsewhere in the code
because it's not specific to the 'extra-line style.

-- 
Antonin Houska
Cybertec Schönig & Schönig GmbH
Gröhrmühlgasse 26
A-2700 Wiener Neustadt
Web: http://www.postgresql-support.de, http://www.cybertec.at

bug#26049: 25.2; Extra lines not added to comment

[Antonin Houska]

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Antonin Houska <ah@cybertec.at> wrote:

> npostavs@users.sourceforge.net wrote:
> 
> > Antonin Houska <ah@cybertec.at> writes:
> > >
> > >> >   	   (progn (goto-char end) (end-of-line) (skip-syntax-backward " ")
> > >> >   		  (<= (point) end))
> > >> >   	   (or block (not (string= "" comment-end)))
> > >> > ! 	   (or block (progn (goto-char beg) (search-forward
> > >> > !                                              "\n"
> > >> > !                                              (min (1+ end) (point-max)) t)))))
> > >
> > >> Maybe (re-search-forward "$" end t) is better?  It's a bit unclear to me
> > >> what exactly all those tests are looking for.  That code could use some
> > >> comments...
> > >
> > > I've just verified your approach - it does work too.
> 
> > "$" also matches at the end of buffer even if it doesn't end in newline
> > (which is a very marginal corner case, I just happened to notice it
> > because I didn't hit RET in my test buffer).
> 
> IMO this is ok. If the 'extra-line value of `comment-style' tells that the
> comment should look like this
> 
> /*
>  * some comment
>  */
> 
> it'd be kind of inconsistend if just a missing RET at the end of buffer
> resulted in this
> 
> /* some comment */
> 
> which effectively means discrepancy from the customization setting.
> 
> (The initial version of my patch ignored the `extra-line' setting in this
> special case, but it was a thinko rather than intention.)
> 
> > 
> > > + 	    ;; Trim trailing whitespace from cs if there's some.
> > > +             (setq cs (string-trim cs))
> > 
> > This would trim leading whitespace too, do we want that?
> 
> I haven't noticed any related issue but yes, string-trim-right is more
> precise. If the (supposedly accidental) leading space should be removed from
> the value of `comment-start', it should probably happen elsewhere in the code
> because it's not specific to the 'extra-line style.

The next version of the patch (with string-trim replaced with
string-trim-right) is below. Is there anything else I should do?

-- 
Antonin Houska
Cybertec Schönig & Schönig GmbH
Gröhrmühlgasse 26
A-2700 Wiener Neustadt
Web: http://www.postgresql-support.de, http://www.cybertec.at


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[-- Attachment #2: newcomment.diff --]
[-- Type: text/x-diff, Size: 1524 bytes --]

diff --git a/lisp/newcomment.el b/lisp/newcomment.el
new file mode 100644
index 1af8929..f2d9735
*** a/lisp/newcomment.el
--- b/lisp/newcomment.el
***************
*** 69,74 ****
--- 69,77 ----
  
  ;;; Code:
  
+ (eval-when-compile
+   (require 'subr-x))
+ 
  ;;;###autoload
  (defalias 'indent-for-comment 'comment-indent)
  ;;;###autoload
*************** the region rather than at left margin."
*** 1139,1144 ****
--- 1142,1150 ----
  
  	  ;; make the leading and trailing lines if requested
  	  (when lines
+ 	    ;; Trim trailing whitespace from cs if there's some.
+             (setq cs (string-trim-right cs))
+ 
  	    (let ((csce
  		   (comment-make-extra-lines
  		    cs ce ccs cce min-indent max-indent block)))
*************** changed with `comment-style'."
*** 1209,1215 ****
  	   (progn (goto-char end) (end-of-line) (skip-syntax-backward " ")
  		  (<= (point) end))
  	   (or block (not (string= "" comment-end)))
! 	   (or block (progn (goto-char beg) (search-forward "\n" end t)))))
  
      ;; don't add end-markers just because the user asked for `block'
      (unless (or lines (string= "" comment-end)) (setq block nil))
--- 1215,1221 ----
  	   (progn (goto-char end) (end-of-line) (skip-syntax-backward " ")
  		  (<= (point) end))
  	   (or block (not (string= "" comment-end)))
! 	   (or block (progn (goto-char beg) (re-search-forward "$" end t)))))
  
      ;; don't add end-markers just because the user asked for `block'
      (unless (or lines (string= "" comment-end)) (setq block nil))

bug#26049: 25.2; Extra lines not added to comment

[Noam Postavsky]

tags 26049 + patch
quit

Antonin Houska <ah@cybertec.at> writes:

> The next version of the patch (with string-trim replaced with
> string-trim-right) is below. Is there anything else I should do?

Could you please add a commit message (see CONTRIBUTE under "Commit
messages" for conventions) and post a version produced via 'git
format-patch' (that way I can grab the patch + commit message
automagically).

Have you assigned copyright for Emacs?  (The patch is small enough to be
applied regardless, but if not you should add
"Copyright-paperwork-exempt: yes" to the commit message.)

bug#26049: 25.2; Extra lines not added to comment

[Antonin Houska]

[-- Attachment #1: Type: text/plain, Size: 684 bytes --]

Noam Postavsky <npostavs@users.sourceforge.net> wrote:

> tags 26049 + patch
> quit
> 
> Antonin Houska <ah@cybertec.at> writes:
> 
> > The next version of the patch (with string-trim replaced with
> > string-trim-right) is below. Is there anything else I should do?
> 
> Could you please add a commit message (see CONTRIBUTE under "Commit
> messages" for conventions) and post a version produced via 'git
> format-patch' (that way I can grab the patch + commit message
> automagically).

See below.

-- 
Antonin Houska
Cybertec Schönig & Schönig GmbH
Gröhrmühlgasse 26
A-2700 Wiener Neustadt
Web: http://www.postgresql-support.de, http://www.cybertec.at


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From e782404ce76c05076b794e9506049d7ed4c55663 Mon Sep 17 00:00:00 2001
From: Antonin Houska <ah@melesmeles.cz>
Date: Mon, 6 Nov 2017 09:59:07 +0100
Subject: [PATCH] Handle single-line comments correctly (Bug#26049)

* lisp/newcomment.el: the comment text had to contain at least one
line break for the ending extra line to be added. The behavior seems
more consistent if the end of the comment text is also considered a
line break.

While fixing this, also removed trailing white space from the comment
initial line (/*).

Copyright-paperwork-exempt: yes
---
 lisp/newcomment.el | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/lisp/newcomment.el b/lisp/newcomment.el
index 2e644c3a99..950f3c85b4 100644
--- a/lisp/newcomment.el
+++ b/lisp/newcomment.el
@@ -69,6 +69,9 @@
 
 ;;; Code:
 
+(eval-when-compile
+  (require 'subr-x))
+
 ;;;###autoload
 (defalias 'indent-for-comment 'comment-indent)
 ;;;###autoload
@@ -1141,6 +1144,9 @@ comment-region-internal
 
 	  ;; make the leading and trailing lines if requested
 	  (when lines
+	    ;; Trim trailing whitespace from cs if there's some.
+            (setq cs (string-trim-right cs))
+
 	    (let ((csce
 		   (comment-make-extra-lines
 		    cs ce ccs cce min-indent max-indent block)))
@@ -1211,7 +1217,7 @@ comment-region-default
 	   (progn (goto-char end) (end-of-line) (skip-syntax-backward " ")
 		  (<= (point) end))
 	   (or block (not (string= "" comment-end)))
-	   (or block (progn (goto-char beg) (search-forward "\n" end t)))))
+	   (or block (progn (goto-char beg) (re-search-forward "$" end t)))))
 
     ;; don't add end-markers just because the user asked for `block'
     (unless (or lines (string= "" comment-end)) (setq block nil))
-- 
2.12.3

bug#26049: 25.2; Extra lines not added to comment

[Noam Postavsky]

tags 26049 fixed
close 26049 26.1
quit

Antonin Houska <ah@cybertec.at> writes:

> Subject: [PATCH] Handle single-line comments correctly (Bug#26049)
>
> * lisp/newcomment.el: the comment text had to contain at least one
> line break for the ending extra line to be added. The behavior seems
> more consistent if the end of the comment text is also considered a
> line break.
>
> While fixing this, also removed trailing white space from the comment
> initial line (/*).
>
> Copyright-paperwork-exempt: yes

Thanks, I rephrased/reformatted the message a bit and pushed to
emacs-26.

[1: db949166ec]: 2017-11-06 19:01:19 -0500
  Handle single-line comments correctly (Bug#26049)
  https://git.savannah.gnu.org/cgit/emacs.git/commit/?id=db949166ecb9aeaa15aa41369a55b3ea6ceaa3b0